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!

Phil’s review of the Digitech AR1946

digitech-AR1946-frontMany thanks to SWLing Post reader, Phil Ireland, who shares his review of the Digitech AR1946:

I’ve now purchased the AR1946 and I have to say, I’m very impressed! No noise problems at all with mine, although if you listen very carefully under certain conditions, you can discern a slight digital hash. Not in anyway imposing though.

This radio is super sensitive, AM comes very close to the CCRadio-EP in performance and FM is outstanding. SW is very impressive but there are a few quirks in tuning:

  • below 10MHz, you hit the Frequency button, key in the value and hit the Frequency button again to tune [to the desired station]
  • above 10MHz, you hit the Frequency button, type in the value and it jumps straight to the frequency [without pressing the Frequency button again].

Not a great issue but worth knowing.

This radio has 7 bandwidths in AM both accessible on MW and SW and rudimentary fine tuning with a separate wheel control. Unfortunately FM only has 1 bandwidth but seems well chosen. DAB+ is not available in Regional NSW so that cannot be commented on.

The telescopic antenna is ridiculously small but seems to pull in the signals with no problems. There are external antenna connections for improved performance.
Audio is very pleasant and you can control both treble and bass with the push of a button. The display is bright, well lit and easy to read with a useful tuning indicator.
There are a number of useful features and with 700 memories, there are more that needed. The radio is very reminiscent of the Grundig Satellit 700 in some respects. Build quality seems very good, time will tell if reliability becomes an issue.

What I don’t like is the radio partially mutes when tuning, this is annoying when bandscanning with the rotary tuning control. I have noticed what appears to be synchronous detection being used as occasionally when tuning onto a frequency, you will hear the detector lock on frequency. If so, there is no control over this feature. That may explain the display showing synch but the final model has automatic synch lock..

The AR1946 dispenses with Airband that was good on the AR1945 and SSB. Its a pity that SSB is omitted but along with the Tecsun PL310ET with DSP, they don’t have SSB capabilities as well. I suspect the same DSP chip is being used in this radio.

Can I recommend the radio? A resounding yes! As mentioned I’m very impressed. Try before you buy, though, as it may be that QC is variable along with many Chinese radios of late.

Digitech-AR1946-Front-HandleMany thanks for your review, Phil!

When Phil notes a lack of noise in his receiver–he’s referring to a previous review we posted from Avo, who complained of internally-generated noise in his AR1946.

It seems, like with many other DSP portables (including the Sangean ATS-405) internally-generated noise may vary from unit to unit. I’m guessing this could have to do with slight variations in the board assembly (variations in soldering, grounding, shielding connections).

As Phil advises, please check your radio immediately after purchase and compare it to another shortwave portable if you have one available. This way, if you detect a noisy receiver, you can get a refund or exchange within the time limits of the return policy.

The Eco USBcell: a LiPo AA USB rechargeable cell

EcoUSBCell

Many thanks to SWLing Post reader, Steven Crawford, who writes:

Avid follower of your SWL Blog and site. I saw these and thought your followers may find these AA and AAA lithium ion USB rechargeable cells may be of interest as they are limited to 1.5 volts. I’m interested for my C. Crane Pocket SW and Sony ICF-SW7600GR as well as for various Mag Instrument flashlights.

An excerpt from PCWorld:

Card-carrying members of the Radio Shack Battery of the Month Club, get ready to salivate: The Eco USBcell is the most exciting development we’ve seen in rechargeable batteries in a long time.

Unlike most rechargeable AA and AAA cells that use nickel metal hydride chemistry, the USBcell’s are based on the same advanced lithium polymer technology that’s used in many smartphones.

That may not sound like a big deal, but one limiting factor in using LiPo in a AA or AAA battery is voltage. LiPo and Lithium Ion’s typical minimum voltage is 3.7 volts and would fry a standard device looking for 1.5 volts.

The Eco USBcell features a power control chip to match the voltage to the standard disposable alkalines we’re used to.

[…]And that’s not even the slick part of the USBcell. Once the battery is dead, you simply pull the top off to reveal a standard USB Type A port. That means there’s no need to carry a charger anymore. Plug it into a 1 amp wall-wart charger and it’ll be topped off in about two hours, even flashing an embedded green LED to let you know. The company says it can technically be charged on a computer’s USB port, but it’ll be a lot slower.

Click here to read the article in PCWorld.

ECOusb-aaThanks, Steven! This is a very cool product, indeed! I noticed that, on BestBuy, there are currently six reviews–dating back to October ’15–with a full 5 star rating. Not bad.

With USB ports and chargers being ubiquitous in our world, I can see where charging these would be very convenient.

My only hesitation is that I have a healthy fear of LiPo batteries after having a GoalZero LiPo pack melt down and burn on my bed while charging once. That was three years ago, however, and charging circuits have become much more reliable since then.

I’ll put these on my wish list and purchase them later in the year if the reviews remain positive. I just purchased a 12 pack of Panasonic Enloop cells, so I’m in no hurry.

Thanks again for the tip, Steven!

By the way, if you’re confused by various battery chemistries, check out our recent rechargeable battery primer by clicking here.

The Kaito KA108: a shortwave portable with built-in record function

Kaito-KA108

Many thanks to SWLing Post reader, Ante, who writes:

Looks like Kaito has a new radio in the works. Portable shortwave receiver with record function. It looks very much like some of the Eton portables.

Here’s Universal Radio’s description:

The Kaito KA108 is a great AM, FM shortwave receiver with a very special feature. It has a record function that allows you to record off the air automatically! It can save the audio to a Micro SD Card or USB Thumb Drive (not included) inserted via the top panel. It also features a large backlit display with battery indicator, signal meter and conventional alarm function with two programmable wake up times.

 

There is a Line Input Jack and stereo earphone output jack. Power input is via a USB port. The KA108 comes with: Li-ion battery and USB charging cable. One year limited mfg. warranty.

Thank you for the tip, Ante! Universal has pricing and availability listed as TBA at time of posting.

I noticed that Amazon has the same radio via Kaito for $67.20 (shipped). Interestingly, the Amazon description reads:

“Kaito KA108 Super Sound quality AM FM Shortwave Radio with MP3 Player and Radio Recorder, Radio Time Schedule Recorder,Alarm Clock+ More”

I hope the “Super Sound” part means that the internal speaker is like that of the Melson S8, with an acoustic chamber. Those speakers have amazing fidelity for such a compact size. Checking this morning, the Amazon listing only has one review–a 5 star–but it wasn’t a verified purchase, had few details on performance and, frankly, smacked of shill a little too much for my taste.

I certainly hope this isn’t simply a Melson S8 with a re-designed body. As I mention in this review, the S8 suffered from terrible internal noise, rendering it useless on shortwave.

Kaito-Ka108-side

The Line In, Phone and DC IN 5V jacks are in the same placement and order as the S8–but the S8 also has the power button and MicroSD card on the side panel, the KA108 has the MicroSD card slot on top, along with a USB thumb drive slot.

Kaito-KA108-Top

I have hope that this is not a re-badged Meson S8 because the KA108 has features the Melson S8 did not, including the ability to record and even schedule recordings!

There are so few portables on the market that can record on the shortwave bands. There are no portables currently on the market that have a sensitive/selective receiver and do a good job of recording.  Even if the KA108’s receiver is only average, if it has a clean recording function, it will be a keeper for me.

My fingers are crossed!

Of course, I will certainly review the Kaito KA108 here on the SWLing Post.  I will most likely wait until Universal Radio has the units in stock, which I imagine will be soon.

A high-gain ferrite bar antenna for the PL-360/PL-365 and CountyComm GP5 series

Ferrite-Bar-Antenna-PL-365-GP5SSB

If you own a Tecsun PL-360, PL-365 or a CountyComm GP5/DSP or GP5/SSB, you might take note of this large ferrite bar antenna offered by a Greece-based seller on eBay.

Ferrite-Bar-PL-365

As you can see in the image above, this antenna is substantially larger than the stock MW antenna supplied by the manufacturer. According to the seller, this ferrite bar antenna has a 10 – 25 db gain over the stock external antenna. I imagine its ability to null unwanted signals is also much better.

The price is about $40 US shipped internationally.

Have any SWLing Post readers ordered this antenna? If so, please share your comments/reviews.

Click here to view the antenna on eBay.

SWLing Post reader, David Korchin, also shares the following demo video on YouTube:

Many thanks to SWLing Post readers, Francis Frankenne and David Korchin for the tip!

Sangean DT-500W: a new AM / FM / Weather Alert Pocket Radio

Sangean-DT-500W-Front

Many thanks to my pal, Jeff McMahon from The Herculodge, who has just apprised me of a new Sangean AM/FM/WX portable: the DT-500W. Jeff learned about the new pocket radio via a comment on his blog.

DT-500W-SideIt appears the DT-500W is powered by a rechargeable Li-ion Polymer 3.7V (1850mAh) battery. I would expect good longevity from a full charge.

Based on the specifications, the receiver covers all NOAA weather radio frequencies, the FM broadcast band (87.5 – 108 MHz) and the full AM broadcast band (520 – 1710 kHz). I also noted on the spec sheet, however, that the AM broadcast (mediumwave) band is limited to 10 kHz tuning steps. Not a great contender for the ultralight DXer or someone who travels outside North America if so!

Click here to view the Sangean DT-500W on Sangean’s website.

As of posting, I can’t find the DT-500W listed with any online retailers.

Thanks again for the tip, Jeff!

The Amateur Astronomer: Tune in to Troy’s Christmas gift

imageSWLing Post reader, Troy Riedel, received a gift like no other from his son this Christmas. No, it wasn’t the fabulous Celestron telescope in the above photo.  On Christmas Eve (December 24) Troy sent the following message:

Merry Christmas, Thomas.

I have to tell you what my son gave me for Christmas a few hours ago.

He purchased 1-hour of radio time for me on WBCQ (5110) for Wednesday, 30 December at 8 P.M. EST.

I will have to pre-record approximately 50-55 minutes over the coming days (not much time to prepare).

After telling my son this is cool – I also added this is the most stressful gift I’ve ever received.

My son suggested I may want to talk about astronomy.

A cool gift, indeed.  Evidently––and even more cool–– Troy is something of a hardcore amateur astronomer. I also encouraged him to do a show on this topic; I can’t think of the last time I heard a show about astronomy on shortwave!

Troy Riedel, host of The Amateur Astronomer

Troy Riedel, host of The Amateur Astronomer

So, despite the challenge of putting a show together in less than a week, Troy confirmed yesterday that he has already completed the show and WBCQ will air it at the following time/frequency:

5,110 kHz on Dec 30, 2015 at 8:00 PM EST (1:00 UTC December 31, 2015)

Troy is looking forward to reception reports and will announce the address during the broadcast.

Oh––and being the good man he is, Troy is also including a PSA for Ears To Our World. Thanks, Troy!

Looking forward to the show!