DX Fiend: Gary DeBock’s guide to building the PL-380 “Pest Control” FSL antenna

Gary-Debock-Pest Control-FSL-PL-380-1SWLing Post contributor, Gary DeBock, is an acclaimed innovator in the realm of Ultralight DXing–he’s well-known for constantly pushing the envelop on these inexpensive DX receivers.

Gary has published yet another detailed home-brew project that can turn your stock Tecsun PL-380 into a Mediumwave DX Fiend!

Many thanks to Gary for the following guest post:


“Pest Control” 4.25” FSL Tecsun PL-380

Put Your Local Noisemakers Down for the Count with this Breakthrough Model

By Gary DeBock, Puyallup, WA, USA

February 2016

Introduction  

The first portable radio with a transplanted FSL antenna was introduced last month (click here to read), providing breakthrough MW-DXing performance in the pocket radio class. Although this 3” Bar FSL Tecsun PL-380 exceeded expectations in every way, its 100mm ferrite bars were in very short supply.

By coincidence the final eBay seller of these 100mm x 20mm x 3mm Russian surplus bars (in Romania) stopped selling them on the day that the first model was finished, creating an instant rush in demand. After providing twelve sets (of 8 bars each) to various DXers my own stock of these bars was rapidly dwindling, and it became an urgent matter to design a similar model using the plentiful 62mm x 12mm x 4mm ferrite bars. Sensitivity of the new FSL antenna would need to be fully competitive with the original model, and I was hopeful of a design that would offer at least one new DXing advantage.

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With the shorter (62mm bars) it would require a larger diameter FSL antenna to come close to the original model in sensitivity, so by necessity this alternative model would need to have a “short and stubby” FSL coil design. After considering this I recalled that most of the antennas with a reputation for exceptional nulling performance (and direction finding) seemed to have such a “short and stubby” coil design—so why not take this opportunity to design and create a portable radio with breakthrough nulling performance, in addition to its superior sensitivity? Such a combination would hopefully make the new model an innovative performer in urban areas—a portable radio that could not only silence multiple MW “pest” stations, but also provide unusual sensitivity to receive competing stations right on the same frequencies. As the model was developed several technical discoveries were made to improve nulling performance, such as the use of grounded shield foil for the Litz wires, and an ultra-symmetrical FSL coil. But even if you live in a rural area far from any MW stations, you will find that this modified radio has a great deal of performance to offer— a combination of sensitivity, selectivity and nulling ability that has never existed in portable form.

Project Overview  

This modification procedure will convert the Tecsun PL-380 AM-LW-FM-SW portable from a modest-performing Medium Wave receiver into an exceptional one, with a significant enhancement of Longwave performance as well. The process involves some close-order soldering on a crowded PL-380 circuit board, and should only be attempted by those will good close-up eyesight, steady hand coordination and some soldering experience. The process also involves the winding of a highly symmetrical antenna coil, which is essential for optimal nulling performance. Because of this, careful attention to the instructions and the use of the recommended ferrite bars and Litz wire is important for the best performance. Certain component parts may be in short supply depending upon current demand, and it is recommended that all these be collected prior to starting the modification procedure.

Since major portions of this project involve duplication of procedures contained in the PL-380 7.5” Loopstick Transplant article, reference is made to various steps and instructions in that article (posted here). As such, hobbyists who have successfully completed the 7.5” loopstick transplant project on a PL-380 will find this procedure relatively simple, with only the 4.25” Bar FSL construction as a new challenge. The resulting FSL-enhanced PL-380 truly provides a quantum leap in MW-DXing performance over the stock model, but reasonable care is necessary to protect the modified portable from sudden drops or mechanical shocks. Completion of the finished radio should provide a great level of satisfaction and hobby enjoyment, especially during travel opportunities where external antennas are impractical or forbidden.

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Construction Parts Required

A.) Tecsun PL-380 AM-LW-FM-SW Receiver (available from multiple sources on eBay)

B.) Precut section of Ace Hardware 48″ orange plastic carpenter’s level (dimensions to follow)

C.) 2.6″ long section of the 3.5″ diameter “Big Boss Noodle

D.) 22 Russian surplus 62mm x 12mm x 4mm ferrite bars

E.) Tube of Duro Super Glue, .07 ounce (or equivalent)

F.) Two 1″ x 1/2″ strips of 1″ I.D. rubber heater hose

G.) 7 1/2″ of 1/8″ diameter shrink tubing

H.) Two 18″ long plastic tie wraps, 125 lb. test

I.) Oatey 4″ x 4″ foam closet spacer pack

J.) Roll of Rite Aid 1″ wide waterproof tape

K.) 40 feet of 250/46 Litz wire

L.) Roll of Scotch “Extreme” shipping tape (any size)

Miscellanious:

  • 8 1/2” x ¾” strip of heavy duty aluminum foil (Reynolds or equivalent)
  • 3” long #18 hookup wire
  • 25w pencil-type soldering iron
  • solder
  • hacksaw (or power miter saw)
  • hand tools

PL-380 Preparation  

Before voiding the warranty on your new PL-380, it’s a good idea to ensure that it has no existing problems which might require warranty service J Install batteries in the radio and give it a test run on all four bands, checking the tuning encoder, clock, volume control, speaker, headphone jack, display functions and digital searching modes. Make sure that the radio is working properly in all functions before starting the modification procedure, since the eBay sellers are unlikely to show you any sympathy after you tear out the stock loopstick. It’s also a good idea to check out the Medium Wave weak signal reception with the PL-380 stock loopstick before starting the modification, to establish a benchmark of performance against which the new 4.25” FSL’s DXing performance will be compared.

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Step-By-Step Construction

1) Follow the detailed cutting procedures in steps 1-9 of the loopstick transplant article (using either a power miter saw or hacksaw) to prepare the FSL antenna mounting frame, HOWEVER please note that the top section length for this project is 3 1/4” (82 mm), NOT 8” as in the loopstick transplant project. The finished precut frame should resemble the picture to the left, with the top section flat, and the bottom section back edge trimmed to allow full use of the radio’s whip antenna. The frame’s entire bottom section (including the glue surface) is identical in both the loopstick and FSL transplant projects.

2) Follow the detailed procedures in steps 17-22 of the loopstick transplant article to prepare the PL-380 cabinet for the FSL transplant procedure.

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3) Refer to the photo above (NOTE: These photos show the original FSL frame cut for the longer 100mm bars, which has a longer top section length than the 3 1/4” on this project’s FSL frame. Ignore this aspect). Place the prepared PL-380 cabinet in the vertical position as shown, with a paper roll (or other item) to keep the cabinet in the vertical position. If necessary sand the edges (only) of the antenna frame’s glue surface to ensure that no cutting debris or rough edges will cause an uneven gluing surface. Use a clean, damp cloth or paper towel to remove all dust and debris from both the antenna frame and PL-380 glue surfaces, then wipe them thoroughly dry. Ensure that maximum light shines on the PL-380’s top glue surface (as shown in the photo below), then practice making multiple “dry runs” of placing the antenna frame directly centered on the PL-380’s front top cabinet surface, with its front edge lined up with the PL-380’s beveled front edge. You will only get one chance to place the frame accurately when the super glue is on the PL-380 surface, so make sure that you know exactly what to do! The antenna frame should sit completely flat against the PL-380 cabinet, and slide across it smoothly if such a test is made. If not, sand any rough edges on the antenna frame’s glue surface and repeat the cleaning procedure.

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4) Refer to the photo above. After ensuring that you are fully prepared for accurate placement of the antenna frame on the PL-380 cabinet, place a 4 1/2” x 3/16” bead of super glue (114 mm x 5 mm) on the PL-380’s front top cabinet surface, as shown in the photo. Refer to the photo on the top of the next page. Ensure that the front side of the antenna frame (as shown) is facing you, then place the antenna frame in a centered position flat against the PL-380 cabinet, with its front edge lining up with the front beveled edge of the cabinet, as shown in the photo. Press the antenna frame down firmly against the cabinet for about one minute, scraping away any excess glue from the front and back edges with a small, flat jeweler’s screwdriver. It is especially important to remove any excess glue from the back edge of the antenna frame in order to allow the PL-380’s back cabinet to close normally. After completion of this step place the PL-380 (with the attached antenna frame) in a secure area until the FSL antenna is constructed.

Construction of FSL Antenna

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5) Refer to the photo at right. Take the precut section of “Big Boss Noodle,” and ensure that the top and bottom cut faces are perfectly straight. Place the section flat on the table as shown, and carefully wrap two lengths of the 1” waterproof tape tightly around the noodle’s circumference, adhesive side out (as shown). Ensure that these tape strips are parallel, and tight enough not to slide up or down. Take a perfectly straight 62 mm bar and press it tightly up against the tape as shown, with its lower edge flat on the table and its longer edges parallel to the noodle’s edges.

Gary-Debock-Pest Control-FSL-PL-380-86) Refer to the photo at right. Carefully press the remaining 21 bars against the waterproof tape, ensuring that their lower edges are flat against the table, and that there are no major gaps in between any bars. (NOTE: These bars occasionally have slightly curved edges, and it may be necessary to turn them upside down or backwards in order for them to fit in well with the adjacent bars. When all of the bars are carefully placed, 22 of them will fit exactly on the noodle’s circumference. If necessary, pull certain bars off of the tape and reposition them for a better fit).

When all 22 bars are positioned in a tidy pattern, wrap two strips of the waterproof tape tightly around them as shown, with the adhesive side out. It is OK if the two tape strips slightly overlap (as shown in the photo), but the two strips should be tight enough so that they don’t slide up or down, and also tight enough to secure the ferrite bar assembly in a circular pattern.

Gary-Debock-Pest Control-FSL-PL-380-97) Refer to the photo at right. Remove the inner staple from the Oatey foam, and locate a 14” (35 cm) length of the foam which is free of holes or imperfections. Cut a straightedge at the beginning of this 14” (35 cm) length of foam, and press this foam edge down on the tape at the position shown in the photo at right, perpendicular to the side of the bar assembly and with one edge of the foam length lined up with one edge of the bar assembly. Wrap the foam length tightly around the circumference of the bar assembly, stretching it slightly to keep it completely flat and lined up with the bar assembly edge. After the foam strip is tightly and completely wrapped around the bar assembly cut another straightedge to mate evenly with the first straightedge, ensuring that there are no gaps or overlaps along the two edges. If necessary, re-stretch and trim the foam strip to mate evenly with the first edge. After once again ensuring a tight wrap of the Oatey foam, secure the two edges with a 3” (76 mm) strip of waterproof tape, as shown in the photo on the previous page.

Gary-Debock-Pest Control-FSL-PL-380-108) Place the assembly in the position shown in the photo at right. Take scissors and trim the loose edge of the Oatey foam so that it is even with the other edge of the bar assembly, as shown in the photo at left. After this trimming both edges of the assembly should be flat, with the assembly forming a perfect cylindrical shape (as shown).

 

9) Refer to the photo below:

Gary-Debock-Pest Control-FSL-PL-380-11Place the assembly on one of its edges, as shown. Take the waterproof tape and tightly wrap one strip along the direct center of the assembly as shown, with the adhesive side out. Ensure that this strip of tape is tight enough so that it will not slide up or down by itself, and then cut the tape with a 2” (51 mm) overlap. If necessary (after wrapping this tape), shift the position of the tape slightly to ensure that it is running along the direct center of the assembly before proceeding with the next step.

10) NOTE: The symmetry of your Litz wire coil will be a major factor in determining the nulling capability of your modified PL-380. When winding the coil keep the Litz wire turns as tight and straight as possible, with no gaps or overlaps.

Gary-Debock-Pest Control-FSL-PL-380-12Refer to the photo on the right. Take the roll of 250/46 Litz wire and measure off 16” (41 cm) from the end. While holding this Litz wire point with one hand pick up the bar assembly with the other hand, and press down the (16”) Litz wire point with the wire parallel to the edge of the tape and 1/8” (3 mm) distant from it, as shown in the photo at left. Keep thumb pressure on this (16”) point while carefully winding a tight first turn of Litz wire around the circumference of the bar assembly, accurately maintaining the 1/8” (3 mm) distance from its edge. After this first Litz wire turn is wound tightly and accurately around the bar assembly it will set the pattern for the remaining turns, which only need to be tightly wound adjacent to the preceding turn.

Since the waterproof tape is wound with the adhesive side out on the assembly, if you need to take a break while winding the Litz wire coil place the assembly down on its edge, not on the adhesive side of the tape. Wrap the second turn tightly adjacent to the first turn, checking around the circumference of the assembly to ensure that there are no gaps or overlaps in the Litz wire turns. Continue this careful process until the entire coil has been wound, as described in the next step.

Gary-Debock-Pest Control-FSL-PL-380-1311) Refer to the photo at right. Continue winding tight, straight turns of Litz wire (with no gaps or overlaps) until the turns are within 1/8” (3 mm) of the other side of the tape. At this point you should have around 21 turns in your Litz wire coil, although the number of turns is not nearly as important as the symmetry of your coil. It should appear completely straight down the center of the assembly, as in the photo at right.

12) Refer to the photo below.

Gary-Debock-Pest Control-FSL-PL-380-14Take the Scotch “Extreme” tape and place a strip across the Litz wire coil at the exact start point (where the 16” point was first pressed down on the tape), ensuring that 16” of loose Litz wire still extends beyond this point for hookup purposes. Ensure that the “Extreme” tape strip is perfectly perpendicular to the Litz wire coil, and that there are no “bubbles” or major wrinkles along its length. Press this tape strip firmly down over the Litz wire coil to secure the coil in a symmetrical position, then trim the ends of the tape even with the edges of the bar assembly.

13) NOTE: To the maximum extent the two ends of the Litz wire coil should be secured by the Scotch “Extreme” tape so that they leave the coil as close together as possible, with no loose runs of single Litz wire along the coil. This factor (along with the use of a grounded shield around the lead-in Litz wires) has proven to have a major effect on the nulling capability of the FSL coil.

Gary-Debock-Pest Control-FSL-PL-380-15Refer to the photo at right. Place a second strip of Scotch “Extreme” tape across the Litz wire coil directly below and within 1/8” (3 mm) of the first strip, securing the other end of the coil where the Litz wire leaves the assembly. Once again ensure that 16” (41 cm) of loose Litz wire extends from the coil, then cut the Litz wire at that 16” (41 cm) point. Ensure that both Litz wires leave the coil freely without binding or kinks, and that the second strip of “Extreme” tape also has no “bubbles” or major wrinkles along its length. Press this second strip of “Extreme” tape firmly down over the coil to finally secure the coil in a symmetrical position, then once again trim the ends of the tape even with the edges of the bar assembly.

Gary-Debock-Pest Control-FSL-PL-380-1614) Refer to the photo above. Take the FSL assembly, 8 1/2” x 3/4” strip of aluminum foil and the 7 1/2” length of 1/8” shrink tubing and place them in the positions shown. Place the strip of aluminum foil under the Litz wires, with the Litz wires running about 1/4” from the right edge of the strip of aluminum foil. Starting as close as possible to the FSL coil (where the Litz wires leave the coil), make a lengthwise fold in the aluminum foil from right to left, covering over the Litz wires for the first 7 1/2” of the aluminum foil (leave 1” at the end of the foil, which will not be folded).. Ensure that the Litz wires are within this initial fold for the 7 1/2” length, then make a second lengthwise fold in the aluminum foil from left to right to securely wrap the Litz wires inside the foil for this first 7 1/2” length. Finally form the aluminum foil into a tight circle as shown, ensuring that neither of the Litz wires is exposed throughout this 7 1/2” length of the foil, and that they are both tightly wrapped in the foil. Also ensure that this entire length of the foil-wrapped Litz wires is of a small enough diameter to easily pass through the 1/8” shrink tubing.

Gary-Debock-Pest Control-FSL-PL-380-1715) Refer to the photo at right. Form the 1” end of the aluminum foil (which does not wrap around the Litz wires) into a compact cylindrical shape, as shown (NOTE: the foil is relatively fragile, and should be handled carefully). Take the loose ends of the Litz wires and pass them through the 1/8” shrink tubing, including the prepared end of the aluminum foil as it approaches that point. While grasping the Litz wires on the right side (as shown) carefully slide the shrink tubing toward the FSL coil, ensuring that it smoothly covers over the foil-wrapped Litz wires (if not, continue forming the aluminum foil into a smaller diameter so that the shrink tubing will easily cover over it. This process should go smoothly with proper preparation). When the shrink tubing is completely covering up the foil-wrapped Litz wires the last 1” section of the aluminum foil should be extending out of the right side of the shrink tubing, as shown in the photo. Handle this aluminum foil section with care in the remaining steps—it is relatively fragile, and should never be pulled for any reason.

Gary-Debock-Pest Control-FSL-PL-380-1816) Refer to the photo at right. Place the viously prepared PL-380 and antenna frame assembly flat on the table, with a protective cloth to keep the front panel display from damage. Take the prepared FSL antenna assembly and place it in the position shown, with the shielded Litz wire shrink tubing running along the back side of the antenna frame, and with the lower edge of the FSL assembly next to the top of the antenna frame. Place the two 1” x 1/2” strips of rubber heater hose in the two positions shown, in between the antenna frame and the FSL antenna and also in between the coil and the FSL edges, with the longer rubber strip dimensions parallel to the FSL edges. Start the two 175 lb. test plastic tie wraps in the positions shown (down the center of the rubber spacer strips), ensuring that the rubber spacer strips remain between the FSL assembly and the antenna frame, and that the spacer strips are centered at the very bottom of the FSL assembly. Also ensure that the Litz wires are in the position shown, with no pinching or binding between the FSL assembly and antenna frame. Slowly and carefully tighten the first plastic tie wrap while ensuring that the rubber spacer strip remains in the proper position. Tighten this plastic tie wrap only enough to securely hold the FSL assembly, and do not tighten it to the point where the ferrite bars’ circular pattern becomes distorted. In a similar manner, carefully tighten the other plastic tie wrap while ensuring that the rubber spacer strip remains in the centered position, in between the antenna frame and FSL assembly. Once again, tighten this tie wrap only enough to securely hold the FSL assembly, and not to the point where the ferrite bars’ circular pattern becomes distorted. When this process is complete the large plastic tie wraps’ clamps should be in the position shown, lined up with each other and in a position to support the radio/FSL combination when the model is laying down flat, on a table. Cut off the excess tie wrap lengths.

Gary-Debock-Pest Control-FSL-PL-380-1917) Refer to the photo at right.   Temporarily place the Litz wires down along the radio’s circuit board in the position shown. Locate the detailed circuit board antenna connection points “AN1” and “AN2” in the close up photo at the top of the next page. After locating these two circuit board connection points (with the Litz wires running in the position shown in the photo at left) place one of the Litz wires over the “AN1” circuit board point, and the other Litz wire over the “AN2” circuit board point. Then measure out about 1” (25 mm) extra Litz wire past these two circuit board connection points, and after making sure that the Litz wires are still in the approximate position shown in the photo at the beginning of this step, cut one (shorter) Litz wire 1” (25 mm) past the “AN2” circuit board point, and one (longer) Litz wire 1” (25 mm) past the “AN1” circuit board point.

NOTE: The proper procedure of tinning the ends of the Litz wires requires that all of the individual Litz wire strands be soldered together at the ends. This requires a clean, shiny solder connection all around the circumference of the Litz wire ends for at least 1/8” (3 mm). When preparing the ends of the Litz wires in the next step, ensure that the ends are tinned in this manner before continuing.

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18) Refer to the photo above. Temporarily remove the Litz wires from the PL-380 cabinet and place them in the position shown, with a protective surface over your work table to avoid hot solder damage. Carefully tin the ends of both Litz wires in the manner described above, working around the circumference of the Litz wire ends with a clean soldering iron for at least 1/4” (6 mm). After doing this, cut off the tinned section on both ends to a length of 1/8” (3 mm). When viewing the ends of the Litz wires after tinning, the entire 1/8” (3 mm) length should be bright and shiny all around its circumference, as shown in the photo at the top of the next page. The cut surface of the Litz wire (the circular face) should also be bright and shiny, with one solid surface of melted solder. Do NOT attempt to tin the 1” section of aluminum foil.

Gary-Debock-Pest Control-FSL-PL-380-2219) Refer to the photo above. Position the shrink tubing as shown, with the tubing entering the PL-380 cabinet near the corner where the wrist strap was previously located. Ensure that there will be sufficient slack in the shrink tubing (as shown) to route it through the empty hole left by removal of the wrist strap without binding (after this hole is enlarged to fit the shrink tubing diameter). Take a small, flat screwdriver and carefully pry apart the cabinet clamp as shown—so that it is wide enough to grip the shrink tubing, but not so wide as to break off.

Ensure that the circuit board points “AN1” and “AN2” still have a small amount of melted solder on them (after removal of the PL-380 stock loopstick, as described in the Loopstick transplant article). Also ensure that there is no excessive length in either of the Litz wires, since these both must be positioned as shown (if necessary, cut one or both to the proper length, and re-tin them as described in the previous step). Place the end of the shorter Litz wire (going to the AN2 circuit board point) down in a horizontal position as shown, and using a MINIMUM of heat (and no additional solder), solder the pre-tinned Litz wire end to the AN2 circuit board point while the wire is in a horizontal position. Carefully observe the connection to ensure that there are no solder bridges to the adjacent circuit board components. After ensuring this, following the detailed procedure described for the AN2 connection above, carefully solder the end of the longer Litz wire to the AN1 circuit board point in a horizontal position as shown, using a MINIMUM of heat (and no additional solder). NOTE: After soldering these connections do not attempt to force either Litz wire down in a horizontal position. Re-solder them in a horizontal position if it is necessary to get them flat against the circuit board.

Gary-Debock-Pest Control-FSL-PL-380-2320) Refer to the photo at right. Take the 3” length of #18 hookup wire and strip off 1/4” of insulation from one end, and 3/4” of insulation from the other end. If you are using stranded wire, twist the individual strands together on each end of the wire. Tin a small amount of solder on the shorter (1/4”) bare length. Locate the “GND” marking on the circuit board as shown in the photo, and using maximum care to keep the wire as flat as possible against the circuit board, solder the tinned end of the hookup wire to the large ground connection on the circuit board immediately to the left of the GND marking. Use only a minimum of heat to make a securely soldered connection, and ensure that there are no solder bridges to adjacent areas.

Cut a 3/4” x 1” section of Scotch “Extreme” tape. While holding the other end of the hookup wire next to (and making a secure electrical contact with) the 1” end of the aluminum foil coming out of the shrink tubing, slide the strip of “Extreme” tape under the connection, and securely wrap the tape around the connection (as shown) to permanently secure the two conductors together. MAKE SURE that these two conductors have a good electrical contact under the tape before continuing, since this connection is important for the model’s optimal nulling capability. During this process avoid rough treatment (or pulling) of the aluminum foil, since it is relatively fragile and easily separated.

Gary-Debock-Pest Control-FSL-PL-380-2421) Refer to the photo above. Using small diagonal cutters carefully clip off small pieces of the back cabinet’s wrist strap hole so that it will be of a similar size to that of the shrink tubing, in order to run the shrink tubing through without any pinching or damage. Ensure that the cut pieces do not fall inside the PL-380 cabinet.

Take the PL-380’s back cabinet section and carefully bring it close to the radio, as shown in the photo. Ensure that the whip antenna’s lead-in wire is not pinched, and also ensure that the shrink tubing is routed is a position close to the empty wrist strap hole in the back cabinet, as shown. As a first step, carefully mate the radio’s back cabinet to the radio’s right side (the one opposite the wrist strap hole) while continuing to guide the shrink tubing through the wrist strap hole. Finally, using a small, flat screwdriver, center the shrink tubing in the center of the wrist strap hole while mating the remaining (left) side of the cabinets together. Ensure that the shrink tubing is not pinched or extremely tight as it is clamped down in this hole. While holding the two cabinet sides together move the whip antenna up and away from the cabinet screw hole underneath, and insert the first cabinet screw, tightening it temporarily to keep the shrink tubing in position. Then insert and tighten the left upper and left lower cabinet screws thoroughly, while snapping the right lower cabinet sections together. Finally, after ensuring that the shrink tubing is still in the center of the wrist strap hole without any binding or excessive stress, tighten the final cabinet screw near the whip antenna base. Reinstall the two small battery compartment screws and reinsert batteries. This completes the assembly of the 4.25” FSL Tecsun PL-380 model.

Initial Testing

If you are not familiar with the PL-380, make sure that you study the owner’s manual to find the location of basic operating controls. It is important to initially test the radio in a location free of computer noise or other RF pollution—preferably in an outdoor location where its capabilities can be appreciated. Refer to the photo on the next page. Turn on the radio and select the Medium Wave band (530-1700 kHz in North America) and set the AM bandwidth control to the most selective (1 kHz) position (NOTE: This position also provides maximum MW and LW sensitivity for the model, although the higher audio frequencies are limited somewhat by the sharp DSP filtering). If your FSL antenna transplant is working properly you should notice an EXCEPTIONAL increase in the signal strength of weak fringe stations relative to the stock PL-380 model, and a very significant increase in fringe station strength relative to a 7.5” loopstick PL-380 model. Check fringe station strength across the band, and you should notice MW reception far superior to that of any stock portable in your collection. If you are not receiving any MW signals the problem is usually easy to trace—either one of the PL-380 circuit board connections is shorted to adjacent components because of too much solder, or the physical stress on the Litz wires (because they were not soldered in a horizontal position) has caused the circuit board connections to break off and separate from the board. In the first case you can attempt to remove excess solder by turning the circuit board upside down and melting the excess solder onto the tip of your soldering iron (or using a “solder sucker” in a normal position), but in the second case you will probably need a technician to restore proper function to your radio. Fortunately both of these problems are rare, and can be entirely avoided by carefully following the instructions in Step19.

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Operation

The triple advantage of superior FSL sensitivity, sharp DSP selectivity and exceptional nulling capability provide this breakthrough model with unprecedented weak-signal performance for a portable—to the extent that after a few DXing sessions the operator may have the impression that the realm of science fiction has been approached.

During DXing sessions it is a good idea to support both the PL-380 and FSL antenna frame in the same hand (as shown in the photo above), and also to avoid sudden mechanical stress or bumps to the antenna frame. When constructed according to this article the glue bond between the antenna frame and PL-380 is sufficient for routine operations, but the DXer should exercise care to avoid bumps, drops or other stress. The FSL antenna itself is fairly rugged, as constructed.

Refer to the photo above. The PL-380 has many digital search functions and advanced capabilities for a pocket radio, but some of the functions of particular interest to the transoceanic DXer are described here. The “AM Bandwidth” switch allows you to choose different levels of DSP filtering to limit splatter from domestic pests, and is usually left in the 1 kHz position for the narrowest filtering while chasing transoceanic DX (although this position does cut off some of the high frequency audio from the desired DX station). The 9/10 kHz switch allows you to change the tuning steps of the radio from the North American (10 kHz) band system to those of the European/ African/ Asian/ Pacific band system (9 kHz), depending upon your preferred DX targets. The MW / LW switch allows you to switch over to Longwave DXing—and you will be pleasantly surprised to discover that your newly installed 4.25” Bar FSL antenna is FAR more sensitive on the Longwave band than the stock PL-380 loopstick. Finally, the Display switch offers you multiple options while chasing transoceanic DX—you can have a 24 hour clock display, a display of the alarm time set in the radio, a constantly changing readout of DX signal strength and S/N ratio, or a temperature display (in either Celsius or Fahrenheit).

Because the antenna frame has been trimmed to allow full operation of the PL-380’s whip antenna to receive SW and FM signals, it’s possible to check the Shortwave parallels of Medium Wave DX stations (and switch back and forth) within a couple of seconds. In general, this “science fiction” PL-380 model’s sensitivity, selectivity and nulling capability will allow you to experience the most exciting AM-DXing fun that a portable can offer—and do so at an unbeatable price.

Nulling Pest Stations

This modified PL-380 was specifically designed to have unprecedented nulling capability for a portable, and when assembled according to the instructions it is capable of razor-sharp nulls on most semi-local and even local MW broadcast stations. Using the nulling function to maximum advantage takes a little bit of practice, and an understanding of the importance of both a horizontal and vertical null angle for different pest stations. It also helps to be in a clean RF environment, away from computer noise, AC house wiring and other limiting factors.

The horizontal null angle is pretty easy to determine—simply point the side of the FSL antenna toward the pest station’s direction until a minimum signal bearing is found. If you have an extremely powerful pest station that makes this impossible to determine on the fundamental frequency, detune the radio (off the pest station’s frequency) by about 10 kHz and try to find the bearing with the minimum pest station splatter .

Once you determine the horizontal null bearing, hold the radio at that bearing and carefully tilt the radio up and down at a slightly vertical angle to determine the absolute minimum signal point. This will be different for each pest station, so it is helpful to write these vertical null bearings down once you determine them, and memorize them if possible. They can be either positive angles (with the radio tilted upward) or negative angles (with the radio tilted downward). The point where the vertical null bearing intersects with the horizontal null bearing will always be the direction of the absolute minimum signal—you can picture this as two lines intersecting at a single point in space. Once the side of the FSL antenna is directed at that point, the signal of most pest stations will disappear into the noise. Since this point can be razor-sharp, it is often helpful to support one side of the radio on a “Lazy Susan” type assembly to keep the radio directed at the horizontal null bearing while you are finding the vertical null bearing.

The closer you are located to a pest station the tougher it will become to null it down into the noise—although this particular model will give you the best possible chance of success. Of course if you are located right next door to a 50 kW pest, you will probably need a little more “science fiction” than this model can provide J

This hard-wired FSL-enhanced PL-380 model is the second in a series of portables designed to be the ultimate “travel radios,” with DXing potential superior to any stock design. It has been a great thrill to design, construct and introduce these models, which are pretty fanatical in both appearance and DXing capabilities. My hope is that their function will inspire those who build and use them, and help them share my impression that the MW-DXing hobby has a very innovative and exciting future!

73 and Good DX,

Gary DeBock


Gary, again, thank you for documenting this procedure so thoroughly! No doubt, many a mediumwave DXer can benefit from the excellent nulling characteristics of your “Pest Control” FSL antenna!

Click here to view other tutorials and articles by Gary DeBock.

Brilliant Article on RTL-SDR Dongle Uses

sdr-Mario2Frequent contributor Mario Filippi N2HUN has written a brilliant piece for the latest edition of The Spectrum Monitor entitled RTL-SDR: Your Eye To The Wireless World, February 2016. Here is a brief synopsis:

RTL-SDR Dongle: Your Eye to the Wireless World

By Mario Filippi N2HUN

The RTL-SDR dongle has garnered much popularity over the last several years as an inexpensive and effective broadband receiver for the radio enthusiast. Now Mario shows us how the RTL-SDR can be pressed into serving in other ways: as a rudimentary piece of test equipment to explore those countless wireless devices that power our world and make life convenient. You can use it when restoring vintage radios, doing frequency analysis, antenna analysis and a host of troubleshooting activities you may never have thought of.

I highly recommend buying at least the current issue ($3.00 / PDF Download – what a steal!) or better yet, subscribing for a whole year. Every issue gives far more value than the cost ($2.00/issue at the current subscription rate).

Mario’s article explores things I never would have thought of, and he explains how he uses these inexpensive dongles in place of much more expensive equipment. It is truly amazing what these little wonders can do, and Mario just keeps pushing back the envelope of what is possible.

Thanks Mario for a truly inspiring article – yet again you have given us even more rabbit trails to explore!

Robert Gulley, AK3Q, is the author of this post and a regular contributor to the SWLing Post. Robert also blogs at All Things Radio.

Expecting a winter storm? Ready your radio

Winter-Storm-JonasMany of us living in the eastern half of North America are bracing for a winter storm this weekend.

If predictions are correct, this storm could dump a lot of snow, sleet, and freezing rain in  many areas.

Winter-Storm-2Of concern to many is the potential for power loss across the region, should this storm have the expected impact. I, myself, live in a rural mountainous area and fully expect to lose power at some point this weekend. (Keep this in mind if you try contacting me.)

Often when a storm is pending, people rush to the stores to buy bread, milk, and eggs. What I concern myself with is stocking up on power!

And you can guess why.  It’s a fact, and a fun one: some of the best shortwave/mediumwave listening conditions happen during a regional power outage. The local noise level simply dives as noisy electronics take a temporary vacation…leaving an opening for some great SWLing.

Here’s my pre-winter storm checklist:

  • Charge batteries
    • Recharge AA cells for portables
    • Charge the internal battery in my CommRadio CR-1a
  • Have the World Radio TV Handbook handy
  • Have several flashlights at the ready (I’m especially partial to the HumanaLight!)
  • Make sure gasoline tanks for the portable generator are topped up
  • Fill the 4×4 with diesel
  • Charge my VHF/UHF Handy-Talkies
  • Oh, yeah…stock pantry/fridge with plenty of food and water

No power?  No problem!  While the snow blows, I’ll feed the fire in the wood stove, brew a steaming pot of joe with my syphon coffeemaker, and cozy up to my warm radio…for a long afternoon of listening.  Ahhh...

SWLing Post readers: How do you prepare for potential power outages?

DX Fiend: Gary DeBock’s guide to building the ultimate FSL antenna for the Tecsun PL-380

Tecsun-PL-380-FSL-1

SWLing Post contributor, Gary DeBock, is an acclaimed innovator in the realm of Ultralight DXing–he’s well-known for constantly pushing the envelop on these inexpensive DX receivers.

This time, Gary has published a detailed home-brew project that can turn your stock Tecsun PL-380 into a Mediumwave DX Fiend!

In Gary’s own words:

This is the “Science Fiction PL-380” model, with the hobby’s first hard-wired FSL antenna in a portable configuration. The radio’s internal Si4734 DSP chip tunes the high sensitivity MW antenna, so there is no need to peak a variable capacitor. For those who can build or obtain this model, it will be a happy new year indeed!

Many thanks to Gary for the following guest post:


3 Inch FSL Tecsun PL-380 Model

Compact Breakthrough in MW Sensitivity, Selectivity and Portability

By Gary DeBock, Puyallup, WA, USA
January 2016

Tecsun-PL-380-FSL-1

Introduction  

Portable radio enthusiasts were astonished when Silicon Labs first introduced their innovative Si4734 DSP chip in 2009—the pocket radios empowered by this new component had amazing DSP-enhanced selectivity. Although the relatively lame stock loopsticks designed by the Kchibo and Tecsun companies seriously limited MW sensitivity there was no shortage of fanatical hobbyists designing upgrade loopsticks in an effort to correct this deficiency. The 7.5” loopstick transplant boosted the MW sensitivity of the PL-380 model up to a much improved level, and it became the most popular modification in our Ultralight radio group.  But in 2011 another huge breakthrough was about to capture the fascination of our DXing niche group—Graham Maynard published his original Ferrite Sleeve article, and the innovative antenna’s sensitivity made our humble pockets radios perform like real transoceanic DXing contenders. This was very thrilling—but was there any possible way that the awesome selectivity from the Si4734 DSP chip and the awesome sensitivity provided by the FSL antenna could somehow be combined in a self-contained breakthrough portable, with lightweight portability as an added bonus?

Tecsun-PL-380-FSL-2

The fact that an Si4734 DSP chip could successfully tune an external antenna was demonstrated by various experimenters (including me) in 2011—a hard-wired 3” Longwave FSL design worked quite well for me in early 2011, and although it was far too heavy to consider attachment to the PL-380 the validity of the hard-wired FSL concept was proven to my satisfaction (see photo at right). The challenge has always been to create a hard-wired FSL that would offer both high MW sensitivity and lightweight portability— a value tradeoff that made this project especially intriguing.

After testing various designs I finally settled on a 3” FSL composed of the lightweight Russian surplus 100mm x 20mm x 3mm ferrite bars. These bars provide a unique balance of high sensitivity and lightweight portability, and the cylindrical shape of the FSL apparently provides the fringe benefit of exceptional nulling capability. The PL-380’s Si4734 chip easily tunes the antenna for breakthrough MW sensitivity from 521-1701 kHz, and provides excellent 1 kHz DSP selectivity as well. The weight of the FSL-enhanced PL-380 is within reason to maintain the concept of easy portability, and its modest size may actually convince airport security agents that it is indeed a radio and antenna combination. Overall the project has been a very satisfying effort to combine the awesome capabilities of both the Si4734 DSP chip and the new FSL antenna– resulting in a breakthrough “travel portable” with astonishing MW-DXing performance.

Project Overview  

This modification procedure will convert the Tecsun PL-380 AM-LW-FM-SW portable from a modest-performing Medium Wave receiver into an exceptional one, with a significant enhancement of Longwave performance as well. The process involves some close-order soldering on a crowded PL-380 circuit board, and should only be attempted by those will good close up eyesight, steady hand coordination and some soldering experience. Certain component parts (such as the 100mm x 20mm x 3mm ferrite bars, the 2.25” Funnoodle inner cores and the orange plastic antenna frames) may be in short supply depending upon current demand, and it is recommended that all these collected prior to starting the project.

Since major portions of this project involve duplication of procedures contained in the PL-380 7.5” Loopstick Transplant article, reference is made to various steps and instructions in that article (posted at

http://www.mediafire.com/view/du3sr5cd9thqvau/7.5inch-LS-PL380.doc ). As such, hobbyists who have successfully completed the 7.5” loopstick transplant project on a PL-380 will find this procedure relatively simple, with only the 3” Bar FSL construction as a new challenge. The resulting FSL-enhanced PL-380 truly provides a quantum leap in MW-DXing performance over the stock model, but reasonable care is necessary to protect the modified portable from sudden drops or mechanical shocks. Completion of the finished radio should provide a great level of satisfaction and hobby enjoyment, especially during travel opportunities where external antennas are impractical or forbidden.

Tecsun-PL-380-FSL-3

Construction Parts Required

A) Tecsun PL-380 AM-LW-FM-SW Receiver (available from many sources, including this eBay listing at $46.99 with free shipping to the USA)  http://www.ebay.com/itm/Tecsun-PL380-DSP-AM-FM-Shortwave-LW-PLL-Radio-Receiver-PL-380-/251783558999?hash=item3a9f783757:g:t0EAAOxylpNTTan7

B) 37 feet of 250/46 Litz wire  http://www.ebay.com/itm/Litz-wire-250-46-0-04-mm-for-crystal-radio-coil-Loop-antenna-100-/160804560511?hash=item2570b2de7f:m:m9fkDfLaAd59_UEmrp1po5w

C) 8 Russian surplus 100mm x 20mm x 3mm ferrite bars (availability currently uncertain– author has a limited supply. An eBay source may reappear for future orders, since many of these bars are presumably still in eastern Europe)

D) 4″ length of 2″ diameter Fun Noodle inner foam core

http://www.amazon.com/Aqua-World-223-Fun-Noodle/dp/B0017QABEQ/

E) Precut orange plastic antenna frame (cut from Ace hardware 48″ plastic level, with 5″ long bottom dimension and 4.5″ top dimension– cutting instructions to follow). NOTE: each Ace Hardware 48” level has enough material to make two FSL antenna frames.

F) Rite Aid 1″ wide waterproof tape (1 roll)

G) Scotch “Extreme” shipping tape (1 roll)

H) Tube of Duro Super Glue (or equivalent), .07 ounce

I) 6 inches of 1/16″ diameter shrink tubing

J) Two 18″ lengths of 125 lb. test plastic tie wraps

K) Two 16″ lengths of 75 lb. test plastic tie wraps

L) Oatey foam pack (4” wide)

M) Two 3/4″ x 1″ strips of 1″ I.D. rubber heater hose

Miscellaneous: Solder, 25w (low heat) soldering iron, hacksaw (or power miter saw), screwdriver set, sandpaper (optional)

PL-380 Preparation

Before voiding the warranty on your new PL-380, it’s a good idea to ensure that it has no existing problems which might require warranty service. (Ha!)

Install batteries in the radio and give it a test run on all four bands, checking the tuning encoder, clock, volume control, speaker, headphone jack, display functions and digital searching modes. Make sure that the radio is working properly in all functions before starting the modification procedure, since the eBay sellers are unlikely to show you any sympathy after you tear out the stock loopstick. It’s also a good idea to check out the Medium Wave weak signal reception with the PL-380 stock loopstick before starting the modification, to establish a benchmark of performance against which the new 3” FSL’s DXing performance will be compared.

Tecsun-PL-380-FSL-4

STEP-BY-STEP CONSTRUCTION

1) Follow the detailed cutting procedures in steps 1-9 of the loopstick transplant article (using either a power miter saw or hacksaw) to prepare the FSL antenna mounting frame, HOWEVER please note that the top section length for this project is 4 ½” (114 mm), NOT 8” as in the loopstick transplant project. The finished precut frame should resemble the picture above, with the top section flat, and the bottom section back edge trimmed to allow full use of the radio’s whip antenna. The frame’s entire bottom section (including the glue surface) is identical in both the loopstick and FSL transplant projects.

2) Follow the detailed procedures in steps 17-22 of the loopstick transplant article to prepare the PL-380 cabinet for the FSL transplant procedure.
Click to enlarge
3) Refer to the photo above. Place the prepared PL-380 cabinet in the vertical position as shown, with a paper roll (or other item) to keep the cabinet in the vertical position. If necessary sand the edges (only) of the antenna frame’s glue surface to ensure that no cutting debris or rough edges will cause an uneven gluing surface. Use a clean, damp cloth or paper towel to remove all dust and debris from both the antenna frame and PL-380 glue surfaces, then wipe them thoroughly dry. Ensure that maximum light shines on the PL-380’s top glue surface (as shown in the photo below), then practice making multiple “dry runs” of placing the antenna frame directly centered on the PL-380’s front top cabinet surface, with its front edge lined up with the PL-380’s beveled front edge. You will only get one chance to place the frame accurately when the super glue is on the PL-380 surface, so make sure that you know exactly what to do! The antenna frame should sit completely flat against the PL-380 cabinet, and slide across it smoothly if such a test is made. If not, sand any rough edges on the antenna frame’s glue surface and repeat the cleaning procedure.<

Tecsun-PL-380-FSL-64) Refer to the photo above. After ensuring that you are fully prepared for accurate placement of the antenna frame on the PL-380 cabinet, place a 4 1/2” x 3/16” bead of super glue (114 mm x 5 mm) on the PL-380’s front top cabinet surface, as shown in the photo. Refer to the photo on the top of the next page. Ensure that the front side of the antenna frame (as shown) is facing you, then place the antenna frame in a centered position flat against the PL-380 cabinet, with its front edge lining up with the front beveled edge of the cabinet, as shown in the photo. Press the antenna frame down firmly against the cabinet for about one minute, scraping away any excess glue from the front and back edges with a small, flat jeweler’s screwdriver. It is especially important to remove any excess glue from the back edge of the antenna frame in order to allow the PL-380’s back cabinet to close normally. After completion of this step place the PL-380 (with the attached antenna frame) in a secure area until the FSL antenna is constructed.Tecsun-PL-380-FSL-7

CONSTRUCTION OF FSL ANTENNA

Tecsun-PL-380-FSL-8

5)   Refer to the photo above. Ensure that the end edges of the 4” Funnoodle inner foam core are perfectly straight before performing this step. Place the inner foam core flat on a table, standing on one of its edges as shown. Take the roll of 1” wide waterproof tape and wrap two turns tightly around the inner foam core as shown in the photo, with the adhesive side out. Ensure that the two turns are wound tight enough so that they will not slide up or down the inner foam core. Take the first 100mm ferrite bar and press it firmly against the waterproof tape with its short edge completely flat on the table, and long edges completely parallel to the edges of the inner foam core (as shown). It is important to place this first bar accurately, in order to start an accurate pattern for the set of 8 bars.

Tecsun-PL-380-FSL-9

6)   Refer to the photo above. Press another of the 100mm ferrite bars against the waterproof tape in a position where it is perfectly flat on the table and perfectly parallel with the first bar, with 1/8” (3 mm) spacing between the bars. Continue to place the other 6 bars on the inner foam core in exactly the same way, ensuring that all 8 bars are flat against the table and parallel with each other, having 1/8” (3 mm) spacing between them. If necessary (after placing all 8 bars on the tape), even out the spacing by moving certain bars slightly so that the gaps between them are all equal. The set of 8 bars will be compressed in the next step to form an octagonal pattern.

Tecsun-PL-380-FSL-10

7)  Refer to the photo above. Place a 75 lb. test plastic tie wrap around one edge of the set of 8 bars as shown, 1/2” (12 mm) from the ends of the bars. Slowly and carefully compress the set of 8 bars as shown, tightening up the slack in the plastic tie wrap gradually as you compress the set of bars. Continue this gradual process until the set of 8 bars forms an octagonal (stop sign) pattern, with the bars barely touching each other on their compressed edges.  At this point take up any remaining slack in the plastic tie wrap, and stop compressing the bars. Repeat this process on the other side of the ferrite bars with another 75 lb. test plastic tie wrap, ensuring that the bars form another octagonal pattern, with their compressed edges barely touching each other. Again take up the slack in the plastic tie wrap, and then use diagonal cutters to trim the excess ends of the plastic tie wraps.

Tecsun-PL-380-FSL-11

8)   Refer to the photo above. Place the prepared set of 8 bars flat on the table on one of its ends, as shown. Take the roll of 1” waterproof tape and tightly wrap two turns of tape around the ferrite bars as shown, with the adhesive side out. Space these two wraps evenly as shown, ensuring that they are tight enough not to slide up and down the bars.

Tecsun-PL-380-FSL-12

9)   Refer to the photo above. Take the Oatey 4” foam pack, remove the center staple and locate a 9” (23 cm) long length of this foam which is free of any holes or imperfections. At the beginning of this 9” (23 cm) long length of foam cut a perfectly straight line perpendicular to the edges of the foam. Press this straight edge of foam down tightly against the waterproof tape as shown, with the edges of the 4” Oatey form lining up with the edges of the bar assembly’s inner foam core. Wrap this Oatey foam tightly around the waterproof tape until the foam touches the plastic tie wrap clamps.

If necessary, re-wrap the foam tightly so that it is centered on the ferrite bar assembly.

Tecsun-PL-380-FSL-1310)   Refer to the photo above. Pull the Oatey foam wrap tightly around the bar assembly, then cut a straight edge to mate evenly with the previously cut straight edge. Before pressing this edge down on the tape cut side notches in the foam where the tie wraps clamps are located, as shown. The press this foam edge tightly down on the tape, mating evenly with the previously cut foam edge. Ensure that there are no gaps or overlaps in the foam edges; if necessary, pull the foam wrap once again all around the bar assembly and cut a new straight edge that will mate evenly, with no gaps or overlaps. Finally, secure this newly cut foam edge with a 2 1/2” (64 mm) strip of waterproof tape, as shown.

Tecsun-PL-380-FSL-14

11)   Refer to the photo above. Support the edges of the prepared bar assembly so that it will be raised off of the table. Wrap two turns of the 1” waterproof tape tightly around the center of the prepared bar assembly, adhesive side out (as shown). When wrapping the second turn, ensure that the inner zigzag edge of the waterproof tape mates evenly with the inner zigzag edge of the first turn of tape, with no overlap or gap.

Tecsun-PL-380-FSL-15

12)   Refer to the photo above. Take your reel of 250/46 Litz wire and measure off 16” (41 cm) of wire from the end. Press this exact point down on the waterproof tape 1/8” (3 mm) from the left edge of the waterproof tape, as shown in the photo. While pressing down this Litz wire point while the wire is in a position parallel to the waterproof tape (as shown) pick up the bar assembly with one hand and the Litz wire reel with the other hand, pulling the Litz wire tightly around the circumference of the bar assembly in a straight, parallel manner to begin the first Litz wire turn. Ensure that this first turn stays 1/8” (3 mm) away from the left edge of the waterproof tape all around the bar assembly, then start the second turn directly adjacent to the first turn, ensuring that no gaps or crossovers occur while winding the turns. Carefully continue this process until 36 total turns have been wound around the bar assembly, which should leave the Litz wire coil in a centered position, similar to the photo below.  NOTE: This coil is designed to provide an inductance of 350 uH.

Tecsun-PL-380-FSL-16

13)   Refer to the photo above. After 36 turns have been wound on the bar assembly, ensure that there is still a 16” (41 cm) length of loose Litz wire leading up to the first coil turn. Then place a strip of Scotch “Extreme” tape along the length of the bar assembly, with the lower edge of the tape along the point where the first Litz wire turn begins (as shown), and with the tie wrap clamps in back of the assembly. Press the tape down firmly to lock the coil into place. In the same manner, turn the bar assembly over and place another strip of “Extreme” tape along the bar assembly, with the lower edge of the tape along the point where the last Litz wire turn ends (where the wire leaves the coil), avoiding the tie wrap clamps. There should be about 2” (51 mm) of space between the two “Extreme” tape strips, and both loose Litz wire ends should be parallel as they come off of the coil. Press the second “Extreme” tape strip down firmly to lock the coil into place. Finally, measure off another 16” (41 cm) of loose Litz wire from the coil, cutting the Litz wire at that point.

Tecsun-PL-380-FSL-17

14)   Refer to the photo above. Cut a 4” (102 mm) length of the 1/16” shrink tubing, and then cut a very short piece off of the ends of the Litz wires to ensure that these ends have the smallest and smoothest possible profile to be run through the shrink tubing. Run one end of the Litz wires through the shrink tubing until about 3 inches of wire extend from the tubing. Carefully insert the other end of the Litz wire through the shrink tubing, and use the procedure (and photo) in Step 30 of the Loopstick Transplant article to run the second Litz wire through the shrink tubing, as shown. The related photo for that procedure is included below.

Tecsun-PL-380-FSL-18

 

Tecsun-PL-380-FSL-19

15)  Place the previously prepared PL-380 and antenna frame assembly flat on the table, with a protective cloth to keep the front panel display from damage.

Take the prepared FSL antenna assembly and place it in the position shown, with the Litz wire shrink tubing running along the back side of the antenna frame and the lower edge of the FSL assembly next to the top of the antenna frame. Place the two 3/4” x 1” strips of rubber heater hose in the two positions shown, in between the antenna frame and the FSL antenna and also in between the coil and the FSL edges, with the longer rubber strip dimensions parallel to the FSL edges. Start the two 175 lb. test plastic tie wraps in the positions shown (down the center of the rubber spacer strips), ensuring that the rubber spacer strips remain between the FSL assembly and the antenna frame, and that the spacer strips are centered at the very bottom of the FSL assembly. Also ensure that the Litz wires are in the position shown, with no pinching or binding between the FSL assembly and antenna frame. Slowly and carefully tighten the first plastic tie wrap while ensuring that the rubber spacer strip remains in the proper position. Tighten this plastic tie wrap only enough to securely hold the FSL assembly, and do not tighten it to the point where the ferrite bars’ octagonal pattern begins to distort. In a similar manner, carefully tighten the other plastic tie wrap while ensuring that the rubber spacer strip remains in the centered position, in between the antenna frame and FSL assembly. Once again, tighten this tie wrap only enough to securely hold the FSL assembly, and not to the point where the ferrite bars’ octagonal pattern begins to distort. When this process is complete the large plastic tie wraps’ clamps should be in the position shown, lined up with each other and in a position to support the radio/FSL combination when the model is laying down flat, on a table. Cut off the excess tie wrap lengths.

Tecsun-PL-380-FSL-20

16)   Refer to the photo above. Temporarily place the Litz wires down along the radio’s circuit board in the position shown. Locate the detailed circuit board antenna connection points “AN1” and “AN2” in the close up photo at the top of the next page. After locating these two circuit board connection points (with the Litz wires running in the position shown in the photo at left) place one of the Litz wires over the “AN1” circuit board point, and the other Litz wire over the “AN2” circuit board point. Then measure out about 1” (25 mm) extra

Litz wire past these two circuit board connection points, and after making sure that the Litz  wires are still in the approximate position shown in the photo at the beginning of this step, cut one (shorter) Litz wire 1” (25 mm) past the “AN2” circuit board point, and one (longer) Litz wire 1” (25 mm) past the “AN1” circuit board point.

Tecsun-PL-380-FSL-21

17) Refer to the photo below. Temporarily place the Litz wires outside of the radio as shown, and install a 1 1/2” (38 mm) long section of shrink tubing over both Litz wires, and a 1” (25 mm) long section of shrink tubing over the longer Litz wire. Position both sections of shrink tubing as shown in the photo below.  Place some type of protective material under the Litz wire so that the soldering procedure (in the next step) will not damage your work surface.

NOTE: The proper procedure of tinning the ends of the Litz wires requires that all of the individual Litz wire strands be soldered together at the ends. This requires a clean, shiny solder connection all around the circumference of the Litz wire ends for at least 1/8” (3 mm). When preparing the ends of the Litz wires in the next step, ensure that the ends are tinned in this manner before continuing.

Tecsun-PL-380-FSL-22

18)   Refer to the photo above. Carefully tin the ends of both Litz wires in the manner described above, working around the circumference of the Litz wire ends with a clean soldering iron for at least 1/4” (6 mm). After doing this, cut off the tinned section on both ends to a length of 1/8” (3 mm). When viewing the ends of the Litz wires after tinning, the entire 1/8” (3 mm) length should be bright and shiny all around its circumference, as shown in the photo at the top of the next page. The cut surface of the Litz wire (the circular face) should also be bright and shiny, with one solid surface of melted solder.

Tecsun-PL-380-FSL-23

19)   Refer to the photo above. Take the prepared ends of the Litz wires and route them as shown in the photo above, with the 1 1/2” (38 mm) section of shrink tubing placed in the cabinet clamp as shown, and the end of the 4” (102  mm) section of shrink tubing (coming from the FSL coil) also positioned as shown (where it will be run through the empty wrist strap hole, in the back cabinet side panel). Before placing the 1 1/2” (38 mm) long section of shrink tubing in the cabinet clamp refer to the picture at the top of the next page, and ensure that there will be sufficient slack in the 4” (102 mm) shrink tubing to be run from the FSL coil to the wrist strap hole (3/8” or 9 mm down from the top of the cabinet) without binding.

Ensure that the circuit board points “AN1” and “AN2” still have a small amount of melted solder on them (after removal of the PL-380 stock loopstick, as described in the Loopstick transplant article). Also ensure that there is no excessive length in either of the Litz wires, since these both must be positioned as shown (if necessary, cut one or both to the proper length, and re-tin them as described in the previous step). Place the end of the shorter Litz wire (going to the AN2 circuit board point) down in a horizontal position as shown, and using a MINIMUM of heat (and no additional solder), solder the pre-tinned Litz wire end to the AN2 circuit board point while the wire is in a horizontal position. Carefully observe the connection to ensure that there are no solder bridges to the adjacent circuit board components. After ensuring this, temporarily move the 1” (25 mm) section of shrink tubing away from the end of the longer Litz wire, and following the detailed procedure described for the AN2 connection above, carefully solder the end of the longer Litz wire to the AN1 circuit board point in a horizontal position as shown, using a MINIMUM of heat (and no additional solder). Once again ensure that there are no solder bridges to adjacent components, and that the wire is in a horizontal position, as shown. Then slide the 1” section of shrink tubing down over the Litz wire to the position shown in the photo.

Tecsun-PL-380-FSL-24

20)   Refer to the photo above. After ensuring that your Litz wire connections and the wires’ positions resemble those in the previous photo, take the PL-380’s back cabinet section and carefully bring it close to the radio, as shown in the photo. Ensure that the whip antenna’s lead-in wire is not pinched, and also ensure that the 4” (102 mm) section of shrink tubing is routed is a position close to the empty wrist strap hole in the back cabinet, as shown. As a first step, carefully mate the radio’s back cabinet to the radio’s right side (the one opposite the wrist strap hole) while continuing to guide the shrink tubing through the wrist strap hole. Finally, center the shrink tubing in the wrist strap hole while mating the remaining (left) side of the cabinets together. Ensure that the shrink tubing is not pinched or extremely tight as it is clamped down in this hole. While holding the two cabinet sides together move the whip antenna up and away from the cabinet screw hole underneath, and insert the first cabinet screw, tightening it temporarily to keep the shrink tubing in position. Then insert and tighten the left upper and left lower cabinet screws thoroughly, while snapping the right lower cabinet sections together. Finally, after ensuring that the Litz wires’ shrink tubing is still in the center of the wrist strap hole without any binding or excessive stress, tighten the final cabinet screw near the whip antenna base. Reinstall the two small battery compartment screws and reinsert batteries.

INITIAL TESTING   If you are not familiar with the PL-380, make sure that you study the owner’s manual to find the location of basic operating controls. It is important to initially test the radio in a location free of computer noise or other RF pollution—preferably in an outdoor location where its capabilities can be appreciated. Refer to the photo on the next page. Turn on the radio and select the Medium Wave band (530-1700 kHz in North America) and set the AM bandwidth control to the most selective (1 kHz) position (NOTE: This position also provides maximum MW and LW sensitivity for the model, although the higher audio frequencies are limited somewhat by the sharp DSP filtering). If your FSL antenna transplant is working properly you should notice an EXCEPTIONAL increase in the signal strength of weak fringe stations relative to the stock PL-380 model, and a very significant increase in fringe station strength relative to a 7.5” loopstick PL-380 model. Check fringe station strength across the band, and you should notice MW reception far superior to that of any stock portable in your collection. If you are not receiving any MW signals the problem is usually easy to trace—either one of the PL-380 circuit board connections is shorted to adjacent components because of too much solder, or the physical stress on the Litz wires (because they were not soldered in a horizontal position) has caused the circuit board connections to break off and separate from the board. In the first case you can attempt to remove excess solder by turning the circuit board upside down and melting the excess solder onto the tip of your soldering iron (or using a “solder sucker” in a normal position), but in the second case you will probably need a technician to restore proper function to your radio. Fortunately both of these problems are rare, and can be entirely avoided by carefully following the instructions in Steps 18 and 19.

Tecsun-PL-380-FSL-25

OPERATION

The triple advantage of superior FSL sensitivity, powerful audio amplification and sharp DSP selectivity provide this breakthrough model with exceptional weak-signal performance for a portable—to the extent that after a few DXing sessions the operator may have the impression that the realm of science fiction has been approached. The cylindrical shape of the FSL antenna seems to provide a bonus capability of unusual nulling function as well, so that multiple weak signals can be received adjacent to (or on the same frequencies as) local pests.

During DXing sessions it is a good idea to support both the PL-380 and FSL antenna frame in the same hand (as shown in the photo above), and also to avoid sudden mechanical stress or bumps to the antenna frame. When constructed according to this article the glue bond between the antenna frame and PL-380 is sufficient for routine operations, but the DXer should exercise care to avoid bumps, drops or other stress. The FSL antenna itself is fairly rugged, as constructed.

Refer to the photo on the previous page. The PL-380 has many digital search functions and advanced capabilities for a pocket radio, but some of the functions of particular interest to the transoceanic DXer are described here.  The “AM Bandwidth” switch allows you to choose different levels of DSP filtering to limit splatter from domestic pests, and is usually left in the 1 kHz position for the narrowest filtering while chasing transoceanic DX (although this position does cut off some of the high frequency audio from the desired DX station). The 9/10 kHz switch allows you to change the tuning steps of the radio from the North American (10 kHz) band system to those of the European/ African/ Asian/ Pacific band system (9 kHz), depending upon your preferred DX targets. The MW / LW switch allows you to switch over to Longwave DXing—and you will be pleasantly surprised to discover that your newly installed 3” Bar FSL antenna is FAR more sensitive on the Longwave band than the stock PL-380 loopstick. Finally, the Display switch offers you multiple options while chasing transoceanic DX—you can have a 24 hour clock display,  a display of the alarm time set in the radio, a constantly changing readout of DX signal strength and S/N ratio, or a temperature display (in either Celsius or Fahrenheit).

Because the antenna frame has been trimmed to allow full operation of the PL-380’s whip antenna to receive SW and FM signals, it’s possible to check the Shortwave parallels of Medium Wave DX stations (and switch back and forth) within a couple of seconds. In general, this “science fiction” PL-380 model’s sensitivity and selectivity will allow you to experience the most exciting AM-DXing fun that a portable can offer—and do so at an unbeatable price.

This hard-wired FSL-enhanced PL-380 model is the first in a series of portables designed to be the ultimate “travel radios,” with DXing potential superior to any stock design. It has been a great thrill to design, construct and introduce this model, which is pretty fanatical in both its appearance and DXing capabilities. My hope is that its function will inspire those who build and use it, and help them share my impression that the MW-DXing hobby has a very innovative and exciting future!

73 and Good DX,

Gary DeBock


Gary, I can only imagine the time and patience it took to document this procedure. Once again, thank you so much for doing so! I have a Tecsun PL-380 and I will–some day–make this “science fiction” mod! 

 

Why Shortwave Radio is Still a Superior Educational Technology

PES-SouthSudan

Children in South Sudan listen to their shortwave radio (Photo: PESS/ETOW)

Reader and contributor Dr. Ed Harris recently authored an excellent article in which he describes why shortwave radio remains a practical and accessible educational technology in today’s world.

And he should know.  Ed––a long-time DXer and world traveler, currently studying to be a ham radio operator––is also a professor of educational leadership at Oklahoma State University College of Education, where he teaches courses in leadership, ethics, and research. Additionally, he oversees the Brock International Prize in Education, which discovers and awards the best ideas in education and showcases them to the world.

Ed is also an Ears To Our World advisory board member––not to mention, a good friend: we’ve travelled together on behalf of Ears To Our World to offer support with educational technologies in parts of the world where they’re needed.

Ed has kindly allowed me to post his full article here on the SWLing Post, as I believe many of you will appreciate this.


whole-earth-catalog

Using  “Whole Earth” Criteria to Explain Why Shortwave Radio is Still a Superior Educational Technology

Ed Harris, Oklahoma State University – College of Education

            As a professor of education, I see concerted efforts across the planet to increase educational opportunities for all global citizens. Governments and institutions are acknowledging that education is vital to social and economic sustainability for everyone, everywhere. For some global citizens, the convergence of the Internet with modern instructional technologies has provided advanced and rewarding educational opportunities.  However, numerous geographical regions are still plagued by educational inequities that result in social and economic disparities.

While there are no quick fixes for these inequities and disparities, the issues can be boiled-down to two interrelated factors:  (1) isolation (i.e., insulation from available and accessible services) and (2) poverty (i.e., insufficient means to procure services). Isolation is a huge problem domestically and abroad. In all parts of the world, rural is rural.  In those areas where people are geographically or politically isolated from available services, the Internet and innovative technologies actually perpetuate educational inequities and widen the digital divide between the have and have-nots.  Moreover, in many areas, the lack of money for basic electricity and Internet subscriptions compound the problem, making educational inclusion virtually impossible.

A few years ago, a colleague and I published an article regarding the above dilemmas in light of the accessibility and sustainability of modern educational technologies.[1] We explained that although we live in the 21st Century, we could benefit significantly from the criteria that “Whole Earth Catalog” used to select sustainable, user-friendly tools for their publications.

For you non-Baby Boomers, the “Whole Earth Catalog” was a collection of creative articles and durable, practical tools published from 1968 to 1972 and sporadically thereafter.[2] Whole Earth editors did not just curate tools; they curated ideas and promoted a philosophy by which to use those tools. Whole Earth technologies were timeless and provided opportunities for personal growth and social development. Before any product was included in the Catalog, it must have met a rigid set of standards:

  1. High quality at a reasonable cost,
  2. Easily accessible,
  3. Useful and relevant to independent or self education, and
  4. Capable of launching a cascade of new opportunities.

Rather than applying the above criteria specifically to radio, we applied them to a wide array of instructional technologies. However, when shortwave radio is held up to the scrutiny of Whole Earth’s standards, readers can see below that radio clearly ascends to the top of the “ed-tech” pyramid.

Standard 1: A Good Tool Offers High Quality at a Reasonable Cost

EtonRadioHigh quality and affordability are obvious factors in any discussion on sustainable technologies. Educators must consider the cost of ownership and return on investment as they seek to adopt new educational technologies. While computers and mobile devices are quite popular in today’s educational settings, their cost prohibits them being used by many across the globe. On the other hand, shortwave radio is relatively inexpensive. Low-cost shortwave receivers can be purchased in almost every part of the world.             Moreover, simple, inexpensive shortwave regenerative receivers can be easily built with a few parts. Even in the most disadvantaged parts of the world, one can find shortwave receivers, and many radios now include hand-cranked devices that provide power without batteries. To add to radio’s cost appeal, listening is absolutely free and does not require special apps or subscription fees.

Standard 2: A Good Tool is Easily Accessible

In the “Whole Earth” days, accessibility was expressed in terms of how easily the technology could be mailed or shipped. For instance, while large harvesting combines were not seen in the publications, sickles, pocketknives and books were prominent. An inaccessible tool is useless, while an accessible tool is invaluable.

Academic fields such as Educational Technology differentiate between (1) availability, which concerns how readily obtainable a technology is, and (2) accessibility, which concerns the skills one needs to successfully employ the technology in the manner intended. An example might be digital library services. Most universities make available a wealth of research materials online for anyone who has university credentials to log in to their system. However, while these materials are available, they are not necessarily accessible to users who are unable to navigate the library website, remember his or her login credentials, or have the search skills to interact efficiently with digital databases. Thus, when adopting new educational technologies, both availability and accessibility must be considered and planned for.

Earth-ClipArtRegarding the accessibility of shortwave transmissions, radio may be the most available and readily accessible technology in the world. Shortwave radio remains the only medium capable of direct communication from one country to listeners in another country without intermediaries such as satellites, cable companies, or Internet providers. Shortwave signals can be accessed anywhere on the planet, and radio is a safe way of providing information to areas of conflict or during an emergency.

Unlike most other radio communications frequencies (such as those used by FM radio, WiFi networks and Mobile Phones) which are limited to local or line-of-sight propagation, shortwave radio signals bounce off the ionosphere and blanket earth with broadcasts and information.  Every corner of the globe can receive shortwave radio broadcasts with even a simple $20 portable radio. When radio is seen as an available, accessible, and affordable educational tool, potential educational opportunities sources dramatically widen and serve to bridge the digital divide.

Standard 3: A Good Tool is Useful for Self-education

ETOW-Uganda-RadioFor educators, self-directed learning (SDL) is a top goal in the educational process. In SDL, the individual learner takes the initiative and the responsibility for what occurs and has the opportunity to choose from a range of available and appropriate resources. Thus, since opportunity and choice can empower a person to grow in his or her capacity to be self-directing, these factors should be nurtured and promoted in educational processes.

The Internet is example of a technology that nurtures self-direction and promotes both informal and formal learning opportunities. However, even the Internet does not surpass radios usefulness in self-education. Research indicates that radio is more than just music, news and entertainment. Rather, radio listening can meet educational needs such as individualized learning, belongingness, self-esteem, independent learning, and even self-actualization in a variety of different ways. Listeners can engage simply by selecting the format type that meets their requirements at any specified period of time.[3]

Moreover, radio listening is edifying because listeners hear current events and ideas from different perspectives across the world. The choices of the learner in radio listening are paramount because he or she can choose the station, choose what they want to get from the experience, and choose with whom they would like to share that experience.

Standard 4: A Good Tool Launches a Cascade of New Opportunities

Opportunity-ClipArtWhole Earth editor Kevin Kelly often reminded readers that all technologies create their own set of problems; however, superior technologies result in new opportunities and ways to solve problems.[4]  Whole Earth was at the forefront of reminding readers of the cycle of  (1) new tool, (2) new challenges, and then back to (3) new tools. In educational terms, when a learner completes a learning cycle, he or she is not only gaining personal and professional knowledge and skills, but impacting future learning as well.[5] The cyclical cascade of opportunities from shortwave radio is impressive. For example:

  • The opportunity of creative imagination and proactive listening. Radio listening feeds imagination and brings an auditory dimension to our lives. It allows for networks of mental associations, and facilitates the listener to vicariously “visit” new places and new cultures. These opportunities serve to facilitate the formation of identity, purpose, and listening skills vital to good communication.[6]
  • The opportunity of connections. Radio listening broadens connections and increases community. Radio listening helps both in making connections of desperate pieces of information and in being connected with each other and to the world. Understanding the interconnection of knowledge is vital in the learning process. Radio listeners hear different perspectives from around the world and are automatically put in the arena of connection making and discernment. Also, radio listening can be a community endeavor in itself.
  • The opportunity of inherent learning about radio. The radio is an educational device, and subjects that can be integrated in radio listening include geography, sociology, politics, mathematics, and a host of others. However, the radio device itself is instructional. Understanding electronics, circuit construction, safety, modes and systems, propagation of radio frequency signals, serving equipment, and progressing host of others.

Summary and Challenge

A good question would be, “Well, did Whole Earth Catalog include shortwave radios in their publications?” The answer is yes. In almost all their publications, radio – i.e., shortwave, amateur, electronics, books/guides, education, and/or communication – was referenced in some way. For example, on page 259 of the special 1994 publication, THE MILLENNIUM WHOLE EARTH CATALOG: Access to Tools and Ideas for the Twenty-first Century, the Sony ICF-SWIOO Receiver was showcased. In that edition, the authors commented, “No alternative yet proposed (satellite radio, personal wireless computer gizmo) offers the same combination of a cheap, portable receiver and program content that crosses borders unfiltered by any government or corporate gatekeeper.”

While technology is constantly evolving, the wisdom of Whole Earth prevails — the wisdom inherent in using technologies that promote a sustainable lifestyle. In education today, we are continually seeking innovative, timeless, and empowering technologies to promote sustained learning for all.  Just as the publishers of Whole Earth Catalog understood, educational technologies are best adopted from grassroots efforts, and those technologies adopted, must empower users to take learning, teaching and research to deeper, more meaningful levels.

The radio has been with us for a long time, is still be a superior instructional technology, and can have an important place in education. However, those of us who have this vision must collaborate to regenerate enthusiasm for this valuable medium as well as devise cost-efficient, user-friendly, and sustainable solutions. Some suggested goals could include the following:

  • Develop school broadcasts that include curriculum-based content and professional development content for educators;
  • Develop and utilize existing language learning programs aimed to teach a variety of languages;
  • Utilize interactive radio technologies that allow for asynchronous feedback and communication;
  • Develop cooperative relationships with regional governments and/or educational institutions to store and broadcast programs for broadcast to the peoples in their respective areas.

Innovative ideas, interconnections through sharing those ideas, and purposeful inclusion of technologies in today’s educational landscape echo the rationale behind Whole Earth Catalog. So in striving for sustainable tools for 21st Century education, as Whole Earth readers were reminded in every issue of the Catalog, we must seek technologies and skills that empower individuals to take ownership of their education, shape their environments, and especially, share the adventure with whoever is interested. When addressing these challenges, shortwave radio is still a viable, superior educational solution.

[1] See Susan Stanberry and Ed Harris’s Back to the future: Revisiting the “Whole Earth” concept of sustainable tools for 21st century education. Journal of Sustainability Education (2015 publication)

[2] While Whole Earth no longer prints a hard-copy version of the Catalog, one can see digital versions at http://wholeearth.com

[3] See Shannon and Brown’s article, Radio Listening as a Function of Basic Human Need: Why Did Maslow Listen to Radio?

[4] See Kelly, K. (2000). “Tools Are the Revolution,” in WHOLE EARTH CATALOG.

[5] Marra, R., Howland, J., Wedman, J., and Diggs, L. (2003). A little TLC (technology learning cycle) as a means to technology integration. TechTrends, 47(2), 15-19. Doi: 10.1007/BF02763419.

[6] See Susan Douglas’s (2004) book, Listening In: Radio and the American Imagination.


Ed Harris can be reached at ed.harris@okstate.edu and would love to hear about your ideas of combining education and radio or advice on the ham exam.

James reviews the Heathkit Explorer Jr. GR-150 TRF AM radio receiver kit

HeathkitExplorerJrMany thanks to SWLing Post contributor, James Surprenant (AB1DQ), who shares this review and photos of the new Heathkit Explorer Jr. TRF AM radio receiver kit:


 Heathkit Explorer Jr. Review

I received this Heathkit kit for Xmas from dear old Dad.

Heathkit Explorer Jr. Manual

The Explorer Jr. manual is very nicely done, spiral-bound, and very reminiscent of the old Heathkit manuals in terms of lay-out and detail.

Heathkit Explorer Jr. Retro envelope packaging

The packaging of the parts is also reminiscent of the old Heathkits with parts grouped into envelopes by phase, ie. “Active Components,” “Passive Components,” “Small Parts,” “Knobs,” etc.

The first night, I worked through completion of the circuit board attaching all electronic components and stopped at the step for winding the coil. I thought it would make sense to start fresh on that step since winding coils is generally a pain.

Even on the first night, I had a few criticisms:

  • A couple of the envelopes were ripped open when I unpacked the kit. There were nuts, bolts, spacers and an Allen wrench loose in the outer box. That said, no parts were missing.
  • I found two errors in the manual:
    1. The color code for one of the resistors was incorrect in the manual. With my aging eyes, and the miniaturization of components today, I always use an ohm meter to test all resistors before attaching them to the PCB when I build a kit.

      Incorrect color code in manual.

      Incorrect color code in manual.

    2. The circuit contains 10 resistors and all 10 were included in the kit. But one was completely missing from the step-by-step instructions. After I finished attaching all active and passive components, I had one resistor left over and fortunately there was a matching empty space on the circuit board for the same value resistor. I double and triple checked the instruction manual and I can not find where it calls for this resistor to be attached.
  • My biggest criticism so far is the fact that this kit is “solder-less.” All components are attached to the PCB with screws, lock washers and a nut. You insert the leads for each component through the over-size pass-through holes on the PCB, and bend the leads tight against the edge. Then you insert a screw in from the topside, place a lock washer on the bottom side and fasten with a bolt.
Bottom of the PCB board

Bottom of the PCB board

On the upside, the fact I didn’t need to work with a hot solder iron meant I felt comfortable building the kit at the kitchen table. (My XYL would not be pleased if she found burn marks on the table!) So I had a nicer environment to work in than the basement work bench.

Heathkit Explorer Jr. sheered off resistor leadsOn the downside, I managed to sheer off the leads on TWO resistors when tightening the screws. Fortunately I was able to replace the busted resistors from my on-hand stock.

The other odd thing about this method of attaching components is that Heathkit included a nifty screwdriver in the kit, but leaves it up to the kit builder to provide a small socket wrench or pliers to hold the nut in place while tightening the screw.

Finally, the instructions call for the kit builder to ‘bend the excess leads back and forth’ until they snap off, rather than instructing the kit builder to snip off the excess leads with nippers. That seemed really strange to me.

Heathkit Explorer Jr. Completed coil

I completed my build of the GR-150 Explorer TRF radio this past weekend. I had no difficulty winding the coil, which involved 56 turns of magnet wire around a ferite core and securing it with transparent tape.

Heathkit provided the black ties, which were too large.

Heathkit provided the black ties, which were too large.

The next problem I encountered was attaching the wound coil to the PCB. The kit came with two zip cords to use as fasteners, but the zip cords were much much too large to fit through the holes drilled in the PCB. So this required a trip to the hardware store.

You can clearly see that the holes are too small for the black cable ties.

You can clearly see that the holes are too small for the black cable ties.

Once I had the coil mounted, I encountered the problem again with the bolts and nuts shearing off the leads – this time, it took me about 4 tries to attach the thin fragile coil wires to the PCB. It’s a very fragile process that again had me wishing this was a solder kit.

Heathkit Explorer Jr. Top of PCB front

The rest of the assembly went well. The only other glitch I encountered was in assembling the cabinet, the kit came with six locking star washers for the cabinet, in fact the parts list indicates that six should have been included in the kit. But then the actual assembly called for 10 star washers.

Heathkit Explorer Jr. Top of PCB

Heathkit Explorer Jr. Nearly finished frontHeathkit Explorer Jr. Completed PCB mounted

So, how did the radio perform? About as expected. It is a single stage TRF receiver without a proper audio amplifier. The instructions say you should use earbuds to listen to the radio, but I found that my standard stereo earbuds to be off too low an impedance for while the radio worked, all stations heard were very faint – about as strong as you’d hear from a typical crystal radio kit.

Heathkit Explorer Jr. 1st run sticker

I hooked the radio up to a set of PC speakers which helped – a lot. Once I could hear the audio output, I was very pleased with the radio’s performance. The tuning cap is geared and it takes a good five turns of the tuning knob to cover the entire broadcast band. The radio was fairly sensitive and not too selective – again, as you’d expect.

So, was it worth it? For me, sure… but it depends on what you are looking for.

It’s a bit pricey for what you get, but if you want to support Heathkit as it attempts to rise from the ashes, and if you have the $$$ to ‘donate’ towards the cause, it may be worth it.

Heathkit Explorer Jr. Completed w. screwdriver

Here is my take:

The good

  • Very nice quality materials….the PCB, tuning cap, and cabinet were of a quality you don’t often see in kits.
  • Nostalgia factor–from the packing to the manuals, the kit really does capture some of the Heath nostalgia.
  • Level of detail in the step-by-step instructions.
  • Documentation. The manual ends with a very nice feature on radio theory and theory of the different stages of the TRF and how to read a schematic. It’s clearly written for a youngster as it’s complete with drawings of smiley-faced electrons moving through the components and circuits.
  • The radio does work and is a joy to tune across the dial.

The bad

  • Quality control is lacking. It’s hard to imagine a kit ever leaving Benton Harbor back in the day with such glaring errors in the manual (wrong color code, missing steps), or with the wrong size zip ties, etc.
  • Price. Even though the materials are high-end, the retail price seems a bit high.

The ugly

  • I really wish Heathkit had included either a built in audio amp circuit (there is plenty of room in the cabinet to add a simple IC-based amp), or would have marketed a separate audio amp kit. Having an amplified speaker would add a lot in terms of pleasure from the completed kit. Another kit vendor, Peebles Originals, peeblesoriginals.com, sells a nice little audio amplifier kit for use with their regen radio kits. I’ve built it, and it’s a simple straight forward kit. Heathkit could have done this and it would have made a big difference. (I think I’ll try my Peebles amp with the Explorer!)

Overall, I really enjoyed the build and I like the radio. I’m looking forward to see what the ‘new” Heathkit does next.

I applaud Heathkit for making a go at a come-back and will continue to support their efforts by buying and building their pricey stuff – yeah, I’m that guy.

73 de AB1DQ
James


James, thank you for not only sharing your experience–along with errors and omissions–but providing excellent, detailed photos. I can’t tell you how many times I’ve been confused by kit instructions and turned to Google to help me find photos and notes from other builders. Your details will help others attempting to build the Heathkit GR-150.

I hope you enjoy your new Heathkit! You’ll have to let us know how that Peebles powered speaker works with the G-150!

Star Wars sound designer is, indeed, a radio enthusiast

StarWars-LogoSWLing Post readers may remember a post I recently published in which I believed I’d identified a familiar shortwave time signal station in the Battle of Hoth scene from The Empire Strikes Back. If you haven’t read this post, feel free to do so and listen to the embedded video/audio clips.

Upon hearing this, I went so far as to muse that the Star Wars sound designer might be a radio listener. I asked our readers if anyone could confirm this–?

Well, we’ve got our answer!  I’m truly indebted to an SWLing Post reader who passed my post along to his friend, Ben, who could provide this definitive response:

“This is Ben Burtt, sound designer of the Star Wars films. A friend sent me a link to this blog thinking I would like to comment.

Ben and old recorders

Ben Burtt with his recording gear, circa 1980. The mike on the stand at Ben’s feet is one from his grandfather’s ham radio station in the 1950s, or possibly earlier.

“The answer is yes, I have always been a ham radio enthusiast.”

 

“My grandfather, Harold Burtt, operated W8CD out of his home in Columbus, Ohio 1930s-1960s. I was enthralled as a kid listening to the sounds on his receiver. I heard alien worlds and cosmic ‘voices.’

Harold Burtt, (Chairman of the Psychology Dept Ohio State) with his attic gear approximately 1935

Harold Burtt, W8CD. (Chairman of the Psychology Dept Ohio State) with his attic gear,  approximately 1935

“So not only did I record his radio, but continued to do so on the Star Wars series and Star Trek as well.

My memory of the Hoth transmission was that it was WWV but it could have been CHU since I was recording all that interested me on the dial.”

Terrific! Thank you, Ben, for taking the time to respond. As I said, you’ve certainly started off this radio enthusiast’s year on the right wavelength…no doubt some of our readers will agree.

Indeed, the powerful sonic experience of the Star Wars and Star Trek films has, in my estimation, helped shape many of us into the radio/sound enthusiasts we’ve become–myself certainly included. Thank you, Ben, for this!  You’ve sharpened my ear to a greater appreciation of sound, especially filmic sound, and your work in particular.    

For readers who are less familiar with Ben Burtt’s work, check out his Wikipedia page and IMDB profile–you’ll find he’s been the sound designer on numerous influential films including the recently released Star Wars: The Force Awakens.

A special thanks to Ben Burtt for sharing these wonderful photos and kindly giving me permission to use them here on the SWLing Post.  I must say, considering my love of radio in the thirties, I especially like that photo of Harold Burtt (W8CD) in his shack.