Tag Archives: Portable Radios

Review of the Digitech AR-1780 portable shortwave radio

The following review first appeared in the October 2017 issue of The Spectrum Monitor magazine.


Earlier this year one of my readers in Australia noted the addition of the Digitech AR-1780 to the product offerings of the Australia and New Zealand-based retailer Jaycar.

One thing I’ve learned over the years is that there are few in-country sources of shortwave radios in both Australia and (especially) New Zealand. Jaycar, in a sense, represents what RadioShack and The Source have offered in the US and Canada––a more accessible electronics retailer with some shortwave radio selection.

Jaycar sells radios badged with the name Digitech. Unfortunately, none of Jaycar’s recent additions––and there have been a few––have been enormous hits among serious radio enthusiasts. The company currently offers five Digitech models: the AR1736 ($18.95 AUD), AR1721 ($25.95 AUD), AR1748 ($129.00 AUD), AR1945 ($159.00 AUD), and now the AR1780 ($129.00 AUD).

The Jaycar models are either very cheap sub-$30AUD digital portables, or pricier large portables with a form factor similar to the Grundig S350DL and S450DLX, or the C.Crane CCRadio-SW. The new AR1780 fits somewhere between––a compact portable that promises a compliment of features tailored for the radio enthusiast.

In this review, we’ll take a close look at the AR1780, starting with its feature set.

Features

What appeals to me about the Digitech AR1780 is the amount of features provided by such a compact, traveller-friendly form factor.

Here’s a comprehensive list of the AR1780’s features and specs:

Frequency coverage:

  • FM 87.5 – 108 MHz
  • MW 522 – 1620 kHz or 520 – 1710 kHz
  • SW 1711 – 29,999 kHz
  • LW 150 – 450 kHz
  • AIR 118 – 137 MHz

Modes:

  • FM (including RDS)
  • AM
  • Single Sideband

Selectable Bandwidths:

  • AM mode: 6, 4, 3, 2.5, 2, & 1.81 kHz)
  • SSB mode: (4, 3, 2.2, 1.2, 1 & 0.5 kHz)

Convenient features:

  • Sleep timer
  • Clock/Alarm
  • Thermometer
  • Signal strength meter
  • Squelch control
  • Voice/Music selectable audio filter
  • Dedicated fine tune control
  • Headphone jack (3.5 mm)
  • Key lock button
  • Key beep on/off
  • Tuning knob and tuning step up/down buttons
  • Display button cycles through alarm, time, temperature, and signal strength
  • FM mono/stereo selection
  • Backlight button
  • Selectable 9/10 kHz regional MW tuning steps
  • Flip-out backstand

Power source: 7 VDC or 4 x AA cells (not included, can be internally charged if NiMH cells)

Antenna: Built-in telescopic and 3.5mm socket for external antenna

Weight: 253g/0.56 lbs (excluding batteries)

Dimensions: 150(W) x 95(H) x 30(D)mm

Operation Manual

The Digitech AR1780 ships with a small user manual. In fact, other than the hand strap, the user manual is the only additional item in the box besides the radio itself.

The manual is quite thin––slightly smaller in height and width than the AR1780––and only contains about eight front-and-back mini pages.  Although readable, it’s littered with grammatical and punctuation errors.  While a manual is certainly a welcome reference item with this feature-packed radio, this manual comes up short, lacking detailed explanations of features and even leaving some out altogether:  it does not, for example, offer any explanation on the use of the excellent squelch control, nor does it fully explain the station memory set on multiple memory pages––!  Rather unfortunate, as these features deserve a clear explanation.

First impressions

The Digitech AR-1780, like many DSP-based portables, includes a handy temperature display which can be toggled for Celsius or Fahrenheit.

I really appreciate the modest, portable form factor of the AR1780, so it had that going for it before I even opened the box. I travel with portable radios a lot, so the compact body of the AR1780 is very appealing. It’s not as compact as the C. Crane CC Skywave series, or the Grundig G6, but is much smaller than my Tecsun PL-660 and PL-880, or my Sony ICF-SW7600GR.

Comparing size: The Tecsun PL-680 (top), Digitech AR1780 (middle), and the C. Crane CC Skywave (bottom)

Unlike the radios mentioned above, the AR1780 does not include some sort of protective case or bag. I believe this is an omission for a radio aimed squarely at the traveler.

Fortunately, the plastic chassis of the AR1780 feels substantial enough. With the key lock engaged, the only likely problem that could arise from having no protective case is damage to the display, such as scratching.

The buttons all have a tactile feedback and seem to respond quickly enough, save powering up the radio, engaging the SSB mode, or changing bands, each of which takes a couple of seconds to engage.

I especially like the fact the AR1780 has, on the right, a dedicated multi-function tuning knob. One can turn the tuning knob to scan frequencies or press it to cycle through fast or slow tuning steps (or to turn off this knob’s function entirely).

The AR1780 also has a dedicated fine tune control––a tuning wheel just beneath the main tuning knob also on the right side of the radio (see image above).  The only odd quirk about this is that this is where most radios have a volume control. Being a creature of habit, many times I’ve inadvertently shifted frequencies when I simply wanted to turn up or down the volume! The volume control, meanwhile, is in the same position on the left side panel of the radio between the antenna and earphone jack.

Speaking of volume, the AR1780 can provide plenty of it-––almost room-filling audio––via the internal speaker. Best yet, I like its balanced fidelity: mellow, with notes of bass, but ample treble when listening at moderate volume. The audio response curve is almost ideal for such a small package.

Something else worth noting: the AR1780 fits nicely in the hand. In general, it’s a great size for portable listening.

Major bonus for a travel radio: the AR-1780 is powered by standard, accessible AA cells. Note that the frequency range information silk-screened on the back stand is incorrect–shortwave coverage extends up to 29,999 kHz.

On the downside, however, one negative I noted shortly after beginning use: muting between frequency steps. In AM mode, this is not as distracting as in SSB mode. Muting makes band scanning a more tedious and fatiguing experience. Unfortunately, in this era of DSP-chip-based receivers, it seems muting has resurfaced.

Also, as with many other DSP portables, you can often hear “input” noise when pressing buttons. In other words, if while listening to one frequency I decide to key in another, I’ll hear a little clicking or buzz in the audio as each button is pressed. This is a very minor annoyance since it only happens when buttons are pressed, nonetheless, I thought it worth mentioning. I often wonder if it’s a result of poor shielding, something from which similar models suffer.

Performance

Over the past two weeks, I’ve had the AR1780 on the air almost every day. I’ve compared it with a number of receivers, but mainly The C. Crane CC Skywave, The CountyComm GP5-SSB, and even the Grundig G6. Below, I break down my notes by band.

AIR band

Let’s start with the “bonus” band: the VHF aviation band.

I’m sure there a number of readers who’ll never use this band, but I am not one of them. Personally, I really enjoy listening to aviation traffic, especially when I travel by air. Since the advent of the AIR band on ultra-compact radios, I no longer feel like I have to lug an additional scanner or receiver just to listen to the local air traffic control; that’s a plus.

Performance-wise, the AR1780 seems to be equal with the CC Skywave on the AIR band. Like the CC Skywave, the AR1780 has a squelch control––a fantastic feature, indeed. Simply tune the radio to your favorite aviation frequency, press and hold in the tuning knob on the side, and then use the tuning knob to adjust the squelch level. I find level 3 or 4 works well.

Note that unlike the squelch on the CC Skywave, the squelch control on the AR1780 actually carries over to the shortwave band. If you have squelch set on the AIR band, then switch to another band where squelch isn’t needed, you will need to turn it off. I never use squelch on the shortwave or mediumwave/AM broadcast bands; normal fading (QSB) can trick the squelch to open and close while tuned to a frequency.

Another convenient feature: press and hold the AIR button to start an automatic scan of the entire band. It’ll run through the AIR band once, saving any active frequencies. This is an ATS feature, so only makes one pass.  I wish you could set it to continuously scan the aviation band in a loop, much as a traditional scanner would.

FM

The AR1780 does a fine job on the FM band. It easily received my benchmark FM stations and even decoded the RDS from one broadcaster about 110 miles from my home base.

When listening to marginal FM signals, the AR1780 can be set to mono mode instead of default stereo mode.

What’s more, the internal speaker is exceptional at handling music––reasonably full fidelity given the limitations of the speaker size.

Longwave/Mediumwave

I’ll be the first to admit that longwave is not an easy band for me to evaluate. Here in North America, there are so few opportunities in the summer to log trans-Atlantic longwave stations. Indeed, unless I’m travelling to New England or the Canadian Maritime provinces, I never try to do so on a portable. I leave TA longwave DXing to my SDRs and tabletops back home where I can listen with the assistance of a large antenna.

But when I travel to Europe, longwave is a must, so my travel radio needs this capability. Based on my ability to receive benchmark LW airport beacons, I’m going to assume the AR1780 will do a fine job receiving European longwave stations while in Europe.

Likewise, the AR1780 should serve you well for both daytime and nighttime reception on mediumwave. Fortunately, switching between 10 and 9 kHz steps is simple: with the radio powered off, simply press and hold the “0” button to toggle between these steps.

On longwave and mediumwave, you can also use SSB mode (both upper and lower sideband). This could come in handy to reject adjacent signal interference on MW.

Likely an oversight on the part of the manufacturer, you can even engage the squelch feature, though why you would on LW and MW, I’m not sure.

Of course, with the fine-tuning control, you can navigate both bands in 1 kHz steps should you desire.

In short: the AR1780 is adequately sensitive on mediumwave and likely on longwave, as well. I wouldn’t rely on it for any serious DXing, but for a travel radio, it will serve you well.

Shortwave

Being first and foremost an avid shortwave listener, I spent the bulk of my AR1780 evaluation time on the shortwave bands and I’m overall very pleased with its performance.

In almost all of my comparisons on the shortwave bands, the AR1780 had a slight edge over its competition, namely, the CountyComm GP5-SSB, the Grundig G6, and the C. Crane CC Skywave.

To be clear, though, it was a very slight performance edge which I think may be attributed to the fact the AR1780’s telescopic antenna is longer, giving it a bit of gain over its competitors. For example, the AR1780’s antenna is about 17.7 cm (7 inches) longer than that of the smaller CC Skywave.

Still, placed on a table and not held in the hand, the AR1780 was able to pull in weak signals better than its competitors. I also compared it with the the Tecsun PL-680––one of my most sensitive shortwave portables––and, not surprisingly, the PL-680 outperformed the AR1780.

Again, I should stress that the sound from the AR1780’s internal speaker is more pleasant to listen to for extended periods than that of its smaller competitors.

SSB

Single sideband reception on the AR1780 is pretty impressive for a radio in this price class. On my particular unit, I found that the fine-tuning control was almost always needed to budge the frequency a few tenths of a kilohertz, even when I knew a particular signal was exactly on frequency. My Grundig G6 always had the same problem––indeed, sometimes in SSB mode, I had to listen “up” as much as 2 kHz on the G6.

The fine-tuning control works very effectively in SSB mode, nonetheless. Audio is quite pleasant, although the noise floor is not quite as low as it is on my larger portables like the Tecsun PL-680, PL-880, and the new S-8800. In my comparison tests, the AR1780 was slightly more sensitive than the CountyComm GP5-SSB, and about equal to that of the Grundig G6.

Click here to watch a short video of the AR-1780 in SSB mode.

In short? SSB is a welcome, capable addition on this compact portable.

Summary

Every radio has its pros and cons, of course. When I begin a review of a radio, I take notes from the very beginning so that I don’t forget my initial impressions. Following is the list I’ve formed over the time I’ve been evaluating the Digitech AR1780:

Pros:

  • Display is clear and easy to read
    • Time is always present via display button
    • RDS info scrolls on lower line
    • Backlit display easy to read
    • Viewing angle good, save from top
  • Dedicated fine-tuning control (even on FM)
  • External antenna jack
  • 9/10 kHz selectable MW steps
  • Time set is simple
  • Adjustable bandwidth in AM and SSB
  • Decent battery life from four standard AA cells
  • Audio from the built-in speaker has better fidelity than other radios in this size

Cons:

  • No bag or carry case
  • DC input voltage is an odd 7V
  • Muting between frequency changes, especially annoying in SSB
  • Sometimes keylock activates backlit display permanently
  • Scan function on AIR band doesn’t loop, it’s an ATS pass only
  • My AR1780 had incorrect information silk-screened on the back regarding frequency coverage
  • Minor: sluggish response when switching bands or modes

Conclusion

Is the Digitech AR1780 worth the price?  I think so. For $129.00 AUD (roughly $103 USD), you’re getting a full-featured radio that is, by and large, a pleasure to operate. It has its quirks, but so do so many ultra-compact portables in this price bracket. It’s certainly worth considering if you live in Australia or New Zealand.

I’d like the AR1780 to be a little more refined:

  • No muting while band scanning in AM or SSB modes
  • A proper scan function to accompany squelch on the AIR band
  • Squelch that doesn’t carry over when bands are switched

What I do think is impressive for this price:

  • Overall smooth audio from the internal speaker
  • Dedicated external antenna port
  • Dedicated tuning and fine-tuning controls
  • Useful screen which displays time and even RDS information
  • Sturdy, relatively long telescoping whip antenna

These are features that make the AR1780 stand out among radios in its price class.

Is it a benchmark performer?  No. But it does the job rather well for the price, and frankly, I think I’ll use this during travel occasionally, even though I have several other smaller portables.

Why?  Well, for one thing, this radio has better audio fidelity from the internal speaker than most of my ultra-compact portables. When I’m in a hotel and listening to a local radio station or even a shortwave broadcaster that’s punching through typical hotel RFI, I’ll appreciate the richer, mellower audio. Many of my smaller portables are lacking in this respect, thus I usually end up listening through headphones.

In fact, the only thing this little receiver lacks for us here in North America is NOAA weather/Environment Canada radio frequencies––but it’s no wonder it’s not included, as it was never intended for this market. But I’m glad the step size on the AM broadcast band can be switched to our 10 kHz spacing, which makes it useful here in North America.

In short, the AR1780 has exceeded my expectations––though admittedly, it may be because it was my first experience with a Digitech radio and I had heard so many lukewarm reviews of previous models.

Regardless, I’m happy I paid a small premium to order this little rig from Down Under.

If you’re a radio enthusiast in Australia or New Zealand who wants the best performance in a portable, and doesn’t mind a larger radio, then do splurge for the Tecsun PL-660, PL-880, or Grundig Satellite. There is a dedicated Tecsun distributor in New South Wales and there are always, of course, retailers on eBay and one of my favorites, Anon-Co in Hong Kong.

And if you’d like to order a Digitech AR1780 outside of Australia or New Zealand, you can purchase from this eBay seller, as I did.

Guest Post: Jerry’s Mediumwave DXing Powerhouse Mini FSL Antenna

Many thanks to SWLing Post contributor, Jerry Popiel, for the following guest post:


PowerhouseFSLAntenna-1

A MW DXing Powerhouse Mini FSL Antenna

by Jerry Popiel

In late February 2016 I completed construction of a modified version of Gary DeBock’s excellent 3 inch Mini FSL design (click here to view).

This new antenna is nothing short of a AM DXing powerhouse with unbelievable sensitivity for receiving stations across the entire AM Bandwidth both day and night. The tuning of stations is razor sharp and it has stunning nulling qualities. Consultation assistance was provided from DXing experts Steve Ratzlaff and Gary DeBock on the project.

Construction Details:

The Antenna was constructed using 9 – 100 mm Ferrite Bars wound on a 2.75 inch diameter x 4 inch styrofoam cake dummy form custom made by in Vancouver, B.C. Canada – (stacy@scoop-n-save.com) for $3.50 plus shipping.

The Coil wire consisted of 38 turns of high gain 660/46 Litz Wire. (Note: As can be seen 38 turns of the thicker Litz Wire left only 5/8” of room on each side of the Styrofoam Form to wire wrap the coil to the ruler frame. A longer Form ie 5” long would work much better for this build).

The insulation spacer used was 2 layers of 1/8 inch Aerotape self adhesive tape which also helped hold the 100 mm Ferrite Bars onto the Styrofoam Coil Form. Inductance measured 356 uH using a DM 4070 Meter which is well within the requirement of over 300 uH for AM Band Reception.

Side View Of 9-Bar FSL Antenna with 2.75” Diameter Styrofoam Cake Dummy.

Side View Of 9-Bar FSL Antenna with 2.75” Diameter Styrofoam Cake Dummy.

Because of the extra thickness of high gain 660/46 Litz Wire which is a bit too big to solder to the inside terminals of the Tecsun PL-380 Radio, a 2 Position Terminal Block was superglued to the outside of the Ruler Frame to act as an interface connection point.

Position Terminal Block Superglued To Back Of Antenna Frame

2 Position Terminal Block Superglued To Back Of Antenna Frame

Testing Results:

Both daytime and evening AM station captures have been spectacular. Stations as far away as KKOB / 770 kHz Alberquerque, New Mexico 1130 Miles from here in Winnipeg, Manitoba, Canada have been received. Country music station WSM / 650 kHz in Nashville, Tennessee 1082 miles distant is a daily evening pickup.

Station KKOB / 770 kHz Alberquerque, New Mexico 1130 Miles distance.

Station KKOB / 770 kHz Alberquerque, New Mexico 1130 Miles distance.

Station WSM / 650 kHz in Nashville, Tennessee 1082 miles distance.

Station WSM / 650 kHz in Nashville, Tennessee 1082 miles distance.

Two Stations Received At 600 kHz 90 Degrees apart at the same time:

The amazing Nulling and Razor Sharp Tuning quality of this FSL was demonstrated when 2 stations at 600 kHz were received at the same time by rotating the Radio with attached FSL 90 degrees. In the North / South direction Station KSJB / Jamestown, North Dakota (219 miles distant) was received with a strong signal strength of 50 / 23. Then by rotating the Radio 90 degrees to the East / West direction Saskatoon, Saskatchewan station CJWW (442 miles distance) was captured with a similar strong signal strength of 44 / 24.

600 kHz Station KSJB / Jamestown, North Dakota.

600 kHz Station KSJB / Jamestown, North Dakota.

600 kHz Station CJWW / Saskatoon, Saskatchewan.

600 kHz Station CJWW / Saskatoon, Saskatchewan.

Daytime Reception of 600 Watt Station 137 Miles Distant:

A major daily AM reception capture during the afternoon illustrating the amazing sensitivity of this antenna is 600 Watt station KKXL Sports Radio 1440 kHz (137 miles).

PowerhouseFSLAntenna-8

All Indoor Reception – For Now!

Due to winter conditions here in Winnipeg, all of the amazing station reception captures in this report were done inside the House facing towards the South window. Fortunately the red ruler platform sides can he used as handles when pointing the radio in the direction of best reception. Exciting times are ahead to see how well this mini 3” FSL will perform outdoors for likely even better AM DXing.

Summarizing:

The design of this new FSL Antenna attached to the Tecsun PL-380 Ultralite radio by Gary DeBock is a major breakthrough in AM DXing since the Radio is attached to the FSL. This new FSL Antenna needs to be constructed to be really appreciated. The application described here requires a bit more skill to construct and is also heavier than the original construction – but at least it is portable. For beginners Gary’s original 3” FSL Heathkit Design is highly recommended and can be reviewed in his You Tube Video posted at: https://www.youtube.com/watch?v=VY9u8MReGjk

Thanks,
Jerry Popiel
Winnipeg, Manitoba, Canada


Thank you, Jerry! It’s amazing what performance you and Gary DeBock have gotten out of these homebrew FSL antennas! Thank you so much for taking the time to share your construction details and performance notes!

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.

Gary-Debock-Pest Control-FSL-PL-380-2

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.

Gary-Debock-Pest Control-FSL-PL-380-3

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.

Gary-Debock-Pest Control-FSL-PL-380-4

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 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.

Gary-Debock-Pest Control-FSL-PL-380-5

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.

Gary-Debock-Pest Control-FSL-PL-380-6

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

Gary-Debock-Pest Control-FSL-PL-380-7

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.

Gary-Debock-Pest Control-FSL-PL-380-21

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.

Gary-Debock-Pest Control-FSL-PL-380-25

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.

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.
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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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! 

 

The Tecsun S-8800: A new receiver in the works

Tecsun-BCL3000-001

SWLing Post contributor, OWL, writes:

It seems that Tecsun has a new large portable in line.

Someone posted a photo of a new Tecsun product catalogue which shows a new model S8800.

The Tecsun BCL-3000 for comparison.

The Tecsun BCL-3000 for comparison.

Apparently it uses the housing of BCL3000 [see above] and is multiple conversion (so a PL880 inside?), DSP based with separate LSB/USB and 10Hz minimum tuning step, and comes with a remote control (for direct frequency input?). Two 18650 batteries are used.

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Photo source: http://bbs.tecsun.com.cn/ via OWL. Click to enlarge.

Tecsun-S8800-Catalog

Photo source: http://bbs.tecsun.com.cn/ via OWL. Click to enlarge.

[Here’s a] link to the post in Tecsun’s web forum:

http://bbs.tecsun.com.cn/0002.asp?open=730351

Many thanks for sharing this find, OWL! This is a very curious development from Tecsun.

I can imagine why Tecsun is re-using the BCL-3000 (a.k.a. Grundig S350DL) body–not only is it roomy inside, but it’s proven to be a popular large portable form factor over the years. Of course, since this is an existing chassis design, design/development costs will be minimal.  If Tecsun is including a remote, I’m sure OWL is correct: it’ll aid with direct frequency entry. The S-8800 will be the first portable shortwave radio with remote control I’ve seen in many years.

If audio is anything like its predecessors, I would expect rich fidelity from the built-in speaker. In terms of performance, though? This is a completely different receiver than the single-conversion BCL-3000, so only time will tell.