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

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


 Heathkit Explorer Jr. Review

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

Heathkit Explorer Jr. Manual

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

Heathkit Explorer Jr. Retro envelope packaging

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

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

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

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

      Incorrect color code in manual.

      Incorrect color code in manual.

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

Bottom of the PCB board

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

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

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

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

Heathkit Explorer Jr. Completed coil

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

Heathkit provided the black ties, which were too large.

Heathkit provided the black ties, which were too large.

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

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

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

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

Heathkit Explorer Jr. Top of PCB front

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

Heathkit Explorer Jr. Top of PCB

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

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

Heathkit Explorer Jr. 1st run sticker

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

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

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

Heathkit Explorer Jr. Completed w. screwdriver

Here is my take:

The good

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

The bad

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

The ugly

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

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

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

73 de AB1DQ
James


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

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

Ramsey Electronics discontinues Hobby Kit Group

Ramsey-KitRamsey Electronics recently announced the following on their website:

ramsey-logo-tinyFor more than 4 decades, the name Ramsey Kits has been synonymous with some of the neatest and the greatest electronic products and hobby kits for the do-it-yourself hobbyist. In those 40+ years, we always thought “outside the box” when we designed a new kit, making us known worldwide as the number one hobby kit manufacturer.

Back in the early 70’s it all started with the infamous “LED Blinky Kit” as our first kit. As the standard first kit sold to schools, scouting groups, and individuals, that one single kit became the very first electronic soldering kit experience for hundreds of thousands of hobbyists. And from that very first kit with only 10 components in it, the 16 page manual was written to delve deep into the circuit to cover how and why it works, in a fun and very easy to understand format. This practice followed over all these years, some 311 products later, earning us praise from everyone from teachers, educators, and engineers, to school children, scouts, and do-it-yourself hobbyists.

While our Hobby Kit Group was busy churning out the kits and products you’ve become so familiar with, our Professional RF Test Equipment Group was busy achieving similar milestones in that industry. From the largest manufacturer of RF pager test equipment, the world’s largest pager test training school, the world standard for cost effective communications service monitors, to our patented RF Isolated Test Enclosures, Ramsey Test has become equally synonymous as the most trusted RF Test Enclosure manufacturer worldwide.

The rapid changes in technologies have made it difficult for the do-it-yourself hobbyist. You just don’t go out and build yourself an 802.11ac wireless router these days! You buy one at the corner big-box store for fifty bucks! One of my favorite kits I personally built was a 25” Heathkit GR295 color TV! It was considered ahead of its time for TV’s, and you had to build it. You just can’t do that today either.

Therefore, following our well respected predecessors like Heathkit, KnightKit, Eico, and others in the past, we are discontinuing our Hobby Kit Group January 1, 2016.

We are extremely proud of our 4 decade heritage of being the leading hobby kit manufacturer worldwide, and consider it an honor that we helped hundreds of thousands of hobbyists make their entry into electronics. We end our heritage with a smile, not a frown, and say thank you, to all our customers and fellow hobbyists.

For our existing Hobby Kit customers, for hobby kits purchased through the end of 2015, our premier tech and warranty support will continue as usual throughout the 2016 warranty period.

To help our Hobby Kit customers obtain some great deals in remaining hobby kit inventory, it has been relocated to Amazon’s fulfillment warehouses, and may be purchased directly at Amazon where you can take advantage not only of low close-out prices, but of their free 2nd day delivery with your Prime membership. The Ramsey Test RF Test Equipment Group is unaffected by this change, and remains to be the leader in RF isolation test equipment throughout the wireless industry.

If you came to this page looking for Ramsey Kit products, we urge you to check with Amazon, you will find some great deals.

If you have any questions or comments about the end of our Hobby Kit legacy, feel free to use the email response form below.

Once again, we feel honored that you trusted Ramsey Kits over these past 4 decades to learn about electronics. All of us in the Hobby Kit Group urge you to continue your pursuit. Some of the nation’s top electronic engineers, scientists, and entrepreneurs started by learning and building hobby kits… pass it on to your kids!

Best regards,

The Ramsey Electronics Hobby Kit GroupRamsey Electronics® | 590 Fishers Station Drive Victor, NY 14564 | 800-446-2295

Click here to search Amazon for Ramey Kits.

DIY Kit for Aircraft Band Monitoring

Aircraft-Band-RadioThere is an interesting kit being sold on eBay designed specifically for aircraft monitoring of 118-136 MHz (meaning it could also cover a number of ACARS frequencies). The receiver is being sold as a DIY kit, a completed kit, or an assembled kit and enclosure. Prices range from ~$16 to $38 plus shipping from Hong Kong. I purchased a kit and enclosure, as building it is part of the fun for me. I will let you know how the construction goes and how the receiver performs after I get the kit together. Delivery time is estimated to be between 2 and 3 weeks, typical of things coming from Hong Kong.

Here is a picture of an assembled board:

swl-aircraft-kit

If anyone has experience with this kit let us know your results!

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

Dave’s Sproutie SPT Beacon

The Sproutie “SPT” Beacon. (Photo source: Dave Richards)

The Sproutie “SPT” Beacon. (Photo source: Dave Richards)

Dave Richards (AA7EE), has just published a brilliant post about his new beacon: the Sproutie SPT Beacon.

Click here to read Dave’s post with detailed instructions for building your own
low power, legal beacon
!

Dave’s beacon is located on 13,558 kHz–he would love your reception reports. Dave notes in his post:

“If you hear the SPT beacon on 13,558 kHz, please send a report – either to the e-mail address listed on my QRZ account [look up call AA7EE], or as a comment underneath this post. Reception reports will be very eagerly received. One gentleman in Seminole County, FL, reported that the area around the SPT frequency was a cacophony of noise in his area, and he stood no chance of hearing it. Those kinds of reports are useful too.  If you put your own HiFER beacon  on the air, do introduce yourself on the LWCA message board, and John can include you on the list of known active HiFER beacons.

Readers: let’s give Dave some reception reports! Though I live on the opposite side of North America, I will certainly be listening!

Dave, thanks again for publishing such an informative and detailed post! You’ve inspired me to build my own beacon.

New kit by NM0S: the 4S-Tuner/Antenna Coupler

4stuner_panelDave Cripe (NM0S) has designed yet another QRP kit for the 4 State QRP Group: the 4S-Tuner/Antenna Coupler.

Description (per Four State QRP Group):

This excellent random wire antenna tuner is the classic T-Match design which is known for wide matching range and smooth operation. Dave has added a nice wrinkle – the SWR indicator employs TWO leds, not the normally seen single red LED. A green one indicates output power with a red one indicating reflected power. The beauty of this arrangement is that the operator sees the output power peaking as the SWR goes down, just like a power meter with dual meters – very intuitive. This makes tuning easier and leaves no doubt that it’s tuned for maximum power output. For a high SWR the red LED is at full brightness and the green LED is off. At 2:1 both are at equal brilliance. At 1:1 the green is full on and the red is off. The small size is perfect for portable operations. Add this dandy little tuner to your portable ops go bag, or use it at home. It’s equally at home on a picnic table, in a tent or camper, as well as on the operating desk in your shack.

Specifications and Design Features

  • Wide tuning range: 80 meters thru 10 meters. Tested on EFHW and 100′ wire.
  • Maximum Power Throughput: tested at 10 Watts.
  • Low loss large toroid
  • Twelve taps for small inductance step selection.
  • Low insertion loss when matched.
  • Enclosure Size: 3″x3″x2″.
  • Pittsburg Construction.

Shipped price is $51.00 (US), $55.00 (Canada), $60.00 (Outside US/Canada).

Dave Cripe designs excellent kits for the ham radio community; they’re easy to build, fun and functional.  If this kit is as popular as his past kits, the first run will most likely sell out in short order.

 Click here to check out the 4S-Tuner/Antenna Coupler at the Four State QRP Group website.

New from Heathkit: the Explorer Jr TRF AM radio receiver kit

HeathkitExplorerJr

The Heathkit Explorer Jr. (Image Source: Heathkit)

Yes, the legendary Heathkit company is back and their first kit is a simple Tuned Radio Frequency (TRF) AM/mediumwave analog receiver: the Explorer Jr.

I knew Heathkit was back in business and under new management, but hadn’t heard any updates as of late. Their president, Andy, just sent a message to the “Heathkit Insiders” group explaining what the team has been up to:

“We’ve designed and developed a wide range of entirely new kit products. We authored the manuals for these kits, complete with the beautiful line art you rely on, preserving and respecting our iconic historic Heathkit style. We developed many new inventions and filed patents on them. We relocated Heathkit, and set up a factory, and a warehouse, and offices, in Santa Cruz, California, near Silicon Valley. We built the back office infrastructure, vendor and supply chain relationships, systems, procedures, operations methods, and well-thought-out corporate structure that a manufacturing company needs to support its customers, to allow us to scale instantly the day we resume major kit sales. All this effort enables us to introduce a fleet of new kits and helps ensure Heathkit can grow, prosper, and continue to bring you great new products for a very long time.”

The Insiders’ message goes into much more detail–I would encourage you to contact Heathkit about joining this group.

The big news in this message was the launch announcement of the Explorer Jr. kit which can be ordered from their website now. The price is $149.95 plus shipping. Heathkit anticipates a 30-day shipping time for the first set of orders.

Here’s a description of the kit from their website:

A Radio Kit Whose Time Has Come.

Again.

When Heath started designing & selling do-it-yourself airplane kits shortly after the Great War, the state-of-the-art in radio was the Tuned Radio Frequency (TRF) design.

A TRF radio was a great deal. If you had a great deal of money. A TRF receiver became a fixture in the homes of families around the world, receiving the news and music AM broadcasts of the day. A family AM radio was a big investment — $100 to $625 in 1929 dollars. (With inflation, that’s $1,400 to $8,700 in today’s dollars.)  Of course, at that price radios also were beautiful. They were made of fine wood, and designed to last. Radios were a visible and attractive furnishing you could be proud to have in your living room or parlor.

Heathkit’s TRF radio is a great deal. And a great deal of radio. This Explorer Jr TM radio is modeled on the original TRF designs, but better. You get to build it yourself. It’s safe and simple enough for beginners to assemble and understand. But it receives AM broadcast stations with performance superior to the vintage radios of 1930.

With the number of Heathkit enthusiasts out there, I suspect this first run of kits won’t last long. The kit trim is available in six colors: Silver, Cranberry, Cucumber Green, Plum Pie, Sapphire Blue, and Tangerine.

Click here to view and order the Explorer Jr on Heathkit’s webstore.

National RF 75-NS-3 receiver kit

NationalRF-75-NS_2

National RF, of California, has introduced a new “semi-kit” receiver: the RF 75-NS-3. Here’s an excerpt from the product description page of the National RF website:

National RF’s 75-NS-3 receiver is a complete super-hetrodyne mini high frequency receiver, designed specifically for the short-wave listener, electronics enthusiast or radio amateur, who wants to use their hands and build a radio. The receiver is offered as a semi-kit in which the electronic assembly is loaded and functionally tested at the National RF facility. The customer must then go to the grocery store (yes…the grocery store!), procure a can of [Spam] lunch meat, eat it or give it to the dog, and then proceed to drill and paint the can, in order for it to become the receiver’s enclosure! […] Detailed drilling instructions and final assembly instructions are provided as part of the kit. All other parts required for completion of the receiver are provided as well. Recognizing that the finished assembly looked somewhat like the fabled Collins receiver of the ‘60s, the 75S-3, (particularly when the can is painted a light gray) National RF engineers dubbed it (with tongue firmly planted in cheek, of course) the 75-NS-3! Although we have had fun packaging this receiver in a lunch meat can, it is nothing to turn your nose at! Its performance and portability will surprise you, and it is an ideal radio to bring with you on any trip!

75-NS_3

The receiver architecture is that of a single conversion super-hetrodyne receiver, that is capable of receiving AM, SSB, or CW. The receiver incorporates a dual gate FET as an RF amplifier with manual peaking and gain controls. A ceramic filter is used in the IF section with a front panel switch that controls a broad or narrow IF response. Other front panel controls include audio drive, BFO setting, and a band switch for the HF bands. The 75-NS-3 has internal receive frequency coils that are switched at the front and rear panels. The frequency range of the receiver, over three band set positions, is 3.5 through 12 MHz. This allows reception of several international short-wave bands, the 80, 60, 40, and 30 meter amateur radio bands, and of course, WWV time and frequency standard stations at 5 and 10 MHz.

For those who simply want a lower cost receiver to monitor the shortwave frequencies, National RF offers two variants of the original receiver: the 75-NS-1 and the 75-NS-2. Both are based on the design and circuit of the 75-NS-3, but do not have the band switching and frequency range of the 75-NS-3 receiver. The 75-NS-1 covers between 3 and 6 MHz, including the 80 and 60 meter amateur band. The 75-NS-2 covers between 6 and 12 MHz, including the 40 and 30 meter amateur bands. Both units have the fixed ceramic resonator band width set for about 6 KHz. And, of course, they are both designed to fit in the tasty potted meat can!! All other specifications presented apply to both of these models as well.

Pricing of the 75-NS-x versions:

  • Type 75-NS-1 Mini HF Receiver Semi-kit (covers 3 to 6 MHz) $189.95
  • Type 75-NS-2 Mini HF Receiver Semi-kit (6 to 12 MHz) $189.95
  • Type 75-NS-3 Mini HF Receiver Semi-kit (band switched from 3.5 through 12 MHz in three switched positions) $269.95
  • Shipping and Handling to within the US $10.00 each

Click here to view on the National RF website.