Many thanks to Davey (KU9L) who shares a link to this news from John (WA3RN), owner, and designer of Penntek radios. John writes:
I have been considering for some time the future of the Penntek Instruments amateur radio products. This old man isn’t getting any younger and is in fact beginning to get tired. With the current production run of the TR-45L QRP transceiver getting close to being complete, I decided that this is a good time to finally retire at 77 years of age and maybe catch a breath. I have therefore chosen not to order parts for another run of these radios. As of late-March 2024, in-house parts remain for about 45 of the standard TR-45L units and about 70 of the “Skinny” version. The remaining TR-35 parts will allow for an additional 65 units, either kits or built radios. As I heard on a radio commercial, “Once they’re gone, they’re gone”. After these remaining radios are sold, I will remain available for repair and service of the Penntek transceivers. Thanks to all those who have purchased and enjoyed WA3RNC products over the years…
It’s no secret that I’m a big fan of Penntek transceivers, so this is sad news. But, I am also very happy for John to make this decision about retiring.
That said, if you’ve been on the fence about buying a TR-45L, TR-45L Skinny, or TR-35, I suggest you do so while John has new units!
These are brilliant radios with excellent audio characteristics, robust front-ends, and some of the best ergonomics you’ll find out there. Keying is smooth and provides proper QSK.
Plus, I think they’re one of the best-looking radios on the market (the TR-45L series especially).
Since all of the Penntek radios started out life as kits, they’re also easy to open and modify/repair.
I don’t have a crystal ball, but I’m willing to bet that once John’s inventory has been depleted, these radios will hold their own on the used market much like other beloved radio models (I’m thinking specifically of the KX1 and MTR-3B). It’ll be interesting to see where used pricing is in, say, 2026.
Again, if you’ve been on the fence, now is the time to make a decision, in my opinion. It looks like John will continue to provide support after his retirement, which is great news as well.
Here’s wishing John all the best in his retirement! Thanks for creating radios that bring so much QRP joy!
Those of you who purchased a fully-assembled and tested version of the QRP Labs QMX are, no doubt, patient people.
While you can order a kit version of the QMX and receive it fairly quickly (still, I believe), the assembled versions take more time as the QRP Labs crew is small and they build and test these by hand.
I ordered mine on June 5, 2023, and it shipped on December 27, 2023.
Truth is, I’ve had a QMX kit since Hans Summers announced it at Four Days In May (FDIM) prior to the 2023 Hamvention. I’ve been meaning to build it but, as many of you know, my life has been a tad crazy these past months and I never got around to it.
I purchased an assembled version of the QMX because I will be reviewing this one and wanted a factory-tested unit. I would have never guessed I’d receive the assembled unit before building it!
Familiar Form-Factor
The QMX looks so much like my QCX-Minis, I’ve gotten them mixed up in the shack! The menu system is very similar to the QCX, but there are some changes to accommodate band changes, modes, etc., as the QCX-Minin series is mono-band CW only.
The QMX, on the other hand, is a five-band, five-watt, multi-mode (CW, Digital, and likely SSB in the future) transceiver. It’s hard to believe you can purchase the QMX for as little as $90 (bare-bones) kit or $165 (fully-assembled and tested).
I initially thought I had an issue with my QMX because it kept shutting down the transmit function. Turns out, that was all user-error. I mentioned the issue on an episode of the Ham Radio Workbench podcast, and a couple of listeners wrote to tell me what I was doing wrong: I was feeding it too much voltage. The QMX doesn’t want more than 12V or so. If the radio detects even a temporary mismatch, it shuts down the TX to protect the finals, etc.
I was unintentionally triggering the QMX’s self-protection functionality!
Once I figured that out, I decided to simply pair my QMX with my Bioenno 3Ah 9V LiFePO4 battery. That would yield about 3 watts of output power and be a comfortable voltage for the QMX.
Vance Historic Birthplace (US-6856)
On Thursday, March 7, 2024, I finally took the QMX outdoors where it belongs! I had a one-hour window of time to complete a full activation. I decided to pair the QMX with my Chelegance MC-750 vertical.
My QMX is a “low-band” version that covers 80, 60, 40, 30, and 20 meters. I thought the top end of its band coverage would serve me best mid-day, so I planned my activation around 20 meters.
Setup was easy and simple. You can see the full set-up process in my activation video below.
Gear:
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Yesterday, I posed the following question and asked for your input:
“Which aspect of a QRP radio holds more importance for you: its ergonomics (ease of use, comfort, display, size, etc.) or its performance (receiver test data, dynamic range, etc.)?”
Thank you to everyone who participated in my recent quickie poll, which has now closed. There were so many interesting points in the feedback. Here are the results from the 252 votes cast within a 20-hour window:
In essence, a slight majority preferred ergonomics, with 57.1% of respondents indicating it as more important, while 42.9% favored performance.
As I mentioned in my previous post, I’m well aware that this question paints with broad brush strokes. There’s not a give-and-take between the two: an investment in the user interface typically doesn’t mean performance is going to suffer. Indeed, I would say most of our modern transceivers sport decent ergonomics and decent performance.
If anything, the relationship between price and performance plays a proper tug of war. Even that’s nuanced, though!
I also received a number of comments and messages from readers who pointed out that my survey was flawed because it didn’t define what I meant by ergonomics and performance carefully enough. I agree that this wasn’t a carefully considered and properly worded poll.
That said, the way I wanted to present this was more like an informal raise of hands–something I often ask for during radio club presentations.
Selection of Comments
The comments from readers were excellent and what I would expect to hear from people who’d raised their hands in a club meeting.
Here are snippets from a few of them, (for all of the comments, click here):
From Scott (KK4Z):
A tricky question. I actually prefer a balance between ergonomics and performance. If you have a good performing radio with mediocre ergonomics, it might not be used to its full potential. A radio with good ergonomics and mediocre performance might be used to its full potential which may be above a good radio with poor ergonomics.
From Mark (NA4O):
My assumption is that performance would have to be good enough for the radio to be in the running. Likewise, ergonomics would have to be good enough for it to be considered usable.
From Nick (KC0MYW):
As I consider the radios that I have and have used and which ones I like better and why, I think that the performance of the radio can almost be considered an ergonomic characteristic with regard to how comfortable and easy the radio is to operate. While a radio with poor ergonomics is not a lot of fun to operate, a lower noise floor and smoother QSK can add as much to the enjoyment level as an easy to access RIT control.
From William (KR8L):
Difficult to say… Since my field operations are very casual affairs I suppose performance is a secondary consideration, although I don’t think I’d enjoy doing a POTA activation with my HW-8.
Ergonomics can be very important — for example, although my FT-817 performs well enough, the number of button pushes and knob twists required to change the keyer speed (or just about any other setting) can be very annoying.
The well thought out controls of my KX2 make it my favorite for field operating, but then it’s a good performer too.
From Brian (K3ES):
Tough question. I will say ergonomics, but what I really mean is easy access to the features I need. I don’t necessarily need contest grade performance, but I do rely on features like a tuner, cw speed adjustment, vfo, etc.
From Emily Clark:
I pick performance for a few reasons: I do contest QRP at times (most recently ARRL RTTY Roundup). I like the filtering, the clarity of the screen, the true FSK for RTTY, and the ability to put an IF spectrum out into N1MM+. I only have wire antennas, and with the AH-705 I virtually do entire contests on my 80m OCFD.
From Michael (N7CCD):
If taken to the extreme on both options, I think I would have to choose performance. I would rather operate a radio that can handle QRM (overloaded front end, etc.) with confusing menus, than the opposite. If not taken to the extreme, then I may choose ergonomics…
From Mark (W8EWH):
Ergonomics for me because I, like many, have many field portable radios and as I cycle between them I need to be able to use them without the need to consult a user manual or waste time fumbling around a menu system looking for a particular feature or setting.
From Shawn (WS0SWV):
Performance! As a retired design engineer, I learned that good design addresses the performance needs of the user(s) in an intuitive manner. If it is cumbersome or overly complex then users will tend to migrate away from it. Some communities have specific ergonomic requirements and for QRP field radios I would argue the primary ones are size, weight, current consumption there are others depending on mode of operation like keyer memories and narrow filters for CW but those are the big ones.
From Wlod (US7IGN):
Different people have different preferences and ideas about ergonomics and performance. It’s important to find a balance, or better yet, have different radios for different tasks.
From Andrew:
Ergonomics is nice, but without performance … it has no use, imagine a coffee mug; it may be hyperergonomical, but then it has a hole at the bottom…
From Dick (K7ULM):
Interesting question. It is interesting how the ergonomics of the KH1 over shadows the performance of the KX2 for some use cases. In some uses the KH1 is definitely the the choice due to its ergonomics. For other radios of its size it will be chosen because of performance and ergonomics. The specific use case is the controling factor IMHO. Performance slightly over ergonomics, generally for me, kind of?
My thoughts?
If there was one comment that reflected my thoughts most closely, it would be this one from John (AE5X):
There’s a lot of overlap between these two characteristics. Too little of one undoes the effectiveness of the other.
I find that most radios do have “good enough” performance (barring an outright flaw or deviation from legal requirements), therefore I pay attention to ergonomics more than to lab numbers of dynamic range and other electronic specs…if I need lab equipment to discern whether or not my radio’s performance is acceptable, it’s acceptable. I don’t like buried menus for commonly-used features.
John’s right. We’re lucky these days in that most of our modern QRP field radios have acceptable performance for our field activities like POTA, SOTA, IOTA, QRP Contests, and some even have the chops for the RF density of, say, Field Day.
If performance is acceptable, I tend to give more weight to ergonomics because it’s important to me that the radio be fun to use.
What makes this show of hands a hot mess, when we look at it under the microscope, is the fact that both ergonomics and performance are nuanced. Herein lies the challenge I find in writing radio reviews: I believe it’s important to explore those nuances so that the review can inform a potential buyer (who might not share my same point of view) in a meaningful way. Sometimes it’s difficult to do that within a print publication’s word count.
Closing thoughts…
As we often say, there is no “perfect” radio that will please everyone, so I think it’s important before we make a purchase decision that we’re realistic with ourselves and understand what we actually value.
Here’s one real-life example–outside the world of QRP transceivers–I’ll share from a friend who, sadly, is now Silent Key. Since I can’t ask for his permission, I won’t mention his name.
Back in 2010, he came to me for advice on buying an SDR (Software Defined Radio)–a PC-connected black box receiver.
Even though not that long ago, keep in mind this was still during the infancy of modern, high-performance, SDRs and most of the options were going to set you back $1,000 or much more. In other words, a substantial investment.
This friend was an avid SWL DXer and was considering an SDR that, at the time, had a slight performance edge over popular SDR models from manufacturers like Microtelecom, RF Space, and WinRadio. I’m not going to call out this SDR by name either, but I’m sure some of you can guess which one I’m referencing.
This particular SDR had fabulous receiver characteristics on paper, but it was well known that the proprietary PC application that controlled it was a bit of a nightmare to use.
My friend purchased it. I tried to help him set this SDR up and learn how to use some of the basic functions and features, but we both found it a struggle. The GUI (graphic user interface), one could tell, was likely designed by the hardware engineer, not someone with experience creating usable software applications, also, unlikely someone who was a DXer or SWL.
He ended up selling this SDR after having owned it for less than a month. He agreed that the performance was brilliant, but hated using the app that controlled it. In the end, he purchased the venerable Microtelecom Perseus and absolutely loved it.
Rob’s advice
This topic of our personal preferences is such a deep one; I think I might put together a club presentation, exploring some of the nuances.
Speaking of presentations, if you’ve never seen Rob Sherwood’s excellent presentation exploring transceiver performance, I highly recommend you check this one out. Rob will be the first to tell you that modern transceivers tend to perform so well that the operator should give weight to ergonomics and usability.
I’m in the midst of writing several radio reviews, and this process always brings up a few inherent dichotomies.
For example—and the point of this quickie poll—some operators seek, first and foremost, a radio with brilliant performance specs. This is especially the case when we’re talking about contest-grade, pricey transceivers. Dynamic range, sensitivity, filtering, and blocking? Yeah, those are looked at very carefully by contesters and DXers.
On the other hand, for some, a radio’s performance is less important than how enjoyable the radio is to actually operate. Are the ergonomics well thought through so that common tasks are easy to perform? Is the display easy to read? Is the encoder weighted correctly? Is the radio compact but useable, etc.?
Even though field radios are typically not thought of as “contest-grade,” many of them have superb contest chops and receivers that can handle RF-dense environments with ease (I’m thinking about my KX3 with roofing filter here).
However, some radios might lack precision filtering and a contest-grade receiver architecture but are designed with field use in mind interface-wise. The Elecraft KX1 and Penntek TR-45L come to mind, although there are many more. Both have great receivers, actually, but the designers obviously placed an emphasis on user a user interface that is field-friendly. I find both such a pleasure to use.
What’s your opinion?
I recognize fully that I’m painting with broad brush strokes here—there are so many other variables in evaluating a radio. I’m sure most of us want a good balance of both performance and ergonomics.
But if pressed for an answer, where do you fall? What do you give higher priority: performance or ergonomics?
If you’d like to cast your vote, please consider participating in the poll below:
You might recall a recent POTA activation where Jonathan (KM4CFT) joined me at the Vance Birthplace K-6856 US-6856–?
Jonathan used my Penntek TR-45L for his portion of the activation, and I was pleased he got to spend some time with this magnificent CW machine. You might also recall that it still had a buzz in the speaker audio–something inside the radio was vibrating.
KM4CFT working the TR-45L in late December 2023.
I tried to track down the buzz as Jonathan operated by tightening some of the screws holding on the speaker grill (yeah, I’m sure that was annoying, and he’ll think again before activating with me in the same space–!). I knew, though, it was something inside the chassis that was vibrating with audio.
As I also mentioned, my TR-45L was a prototype unit (I helped Beta test it)–it had a couple of mods and wasn’t exactly representative of the upgraded production model.
John (WA3RNC) at Penntek reached out to me after I published my recent field report and video; he offered to upgrade my TR-45L to the production chassis which would sort out the buzz. I was most grateful, of course!
He then asked if I would be interested in checking out the TR-45L “Skinny,” which is essentially a TR-45L in a much skinnier chassis. The Skinny model lacks the ATU and battery options but is lighter weight and more portable. I mentioned to John that I’d like to purchase one, actually. Since John was interested in sponsoring QRPer, we ended up working out a barter (at full market price) for ad space. I love this arrangement, actually, because I was going to approach him about sponsorship at some point anyway.
The Skinny!
Now keep in mind that the TR-45L is one of my favorite CW radios. I love the audio, the receiver characteristics, and the “Apollo era” aesthetic. I think it’s one of the best-looking and best-sounding radios on the market.
The Skinny is just like the bigger TR-45L, just roughly half the depth. I did have concerns that the audio wouldn’t be as good since the acoustic chamber would be smaller, but turns out, I had nothing to fear. The Skinny’s audio is on par with its bulkier sibling.
There was no learning curve with the Skinny because 1.) it’s identical in operation to my TR-45L and 2.) Penntek radios have super simple interfaces, and almost every function has a top-level direct control.
Zebulon Vance Birthplace (US-6856)
On Tuesday, February 27, 2024–the day after receiving the TR-45L Skinny–I packed it up and took it to the Vance Birthplace for its inaugural POTA activation!
That day, I had about 90 minutes to enjoy an activation, and I was looking forward to spending time with the new Skinny.
Vance was a great choice that day because the weather was moody; it was gusty, rainy, and I knew their picnic shelter would provide excellent cover.
The Skinny (in its padded bag), the MC-750 and my ABR cable assembly.
The TR-45L Skinny, unlike my original TR-45L, has no internal Z-Match ATU, nor does it have an internal battery. In fact, there’s no room for either in the Skinny, so it’s not even an option.
I paired the Skinny with my Chelegance MC-750, which is a resonant antenna when deployed correctly, so there was no need for a matching device. I supplied power via one of my 3Ah Bioenno LiFePO4 batteries.
Setup was simple and easy!
Gear:
Note: All Amazon, CW Morse, ABR, Chelegance, eBay, and Radioddity links are affiliate links that support QRPer.com at no cost to you.
I recently acquired an Index Labs QRP Plus transceiver (more on that in a future post!).
This little rig was produced in the mid to late nineties and, to my knowledge, was one of the first 160-10 meter, field-portable, general coverage QRP transceivers on the market. The only other one I can think of was the Ten-Tec Argonaut II, but please correct me if I’m wrong on this point.
QST ad from 1995 courtesy of WD8RIF.
I’m just curious if anyone here ever owned one and what they thought of it? Please comment!
On Sunday, March 3, 2024, I had a couple of errands to run in downtown Asheville and also had to pick up my daughter.
I ended up having about 40 minutes to kill and, since I had my Elecraft KH1 field kit packed in my EDC bag, I thought it might be fun to fit in a little radio time.
Since I was downtown, the only viable POTA site to hit would be the Thomas Wolfe Memorial–you might recall my activation there last year–but technically, the park was closed. It is an urban park in the middle of Asheville, and there are no gates to keep people from walking across the grounds, but still, I’d feel better activating with permission from the staff first. (I’m pretty sure they’ll grant that permission, by the way.)
Instead of activating, I decided to do a little POTA hunting.
I parked at the spot where I planned to meet my daughter and grabbed my KH1 field kit.
My good friend, Ara (N6ARA), designed a small 3D-printed adapter that allows his TinyPaddle Plug to fit the KH1 securely. He sent me (free of charge) this new key/adapter to evaluate.
The adapter is a super simple design that works with the TinyPaddle Plug (not the TinyPaddle Jack).
I hadn’t used this new adapter in the field yet–I only very briefly tested it at the QTH a couple of days prior.
I mentioned last year, shortly after the KH1 was introduced, that I expected a number of 3rd party paddles to start appearing on the market. Since the interface with the KH1 is a standard 3.5mm plug, it does open the door to 3D-printed designs and experimentation. Admittedly, it’s a small space to fit in a paddle, but it’s doable.
I believe N6ARA was actually the first non-Elecraft paddle I used on my KH1 because his TinyPaddle Plug will fit it natively. That said, the new KH1 adapter makes it a proper secure fit–the way it should be!
Side Note: The OEM Elecraft KH1 paddles (the KHPD1s) are now in Revision 2, and all KH1 owners (who received the original paddles) will get version 2 paddles eventually via Elecraft for free.
The original KH1 paddles have a green circuit board.
I haven’t received my Rev 2 paddles yet, but I know I will before long. It’s my understanding that the Rev 2 paddles have a much better feel, and keying is more accurate.
Still…it’s brilliant that Elecraft used a standard jack so that we hams can design our own paddles if we like.
The TinyPaddle Plug
Ara’s TinyPaddle design is super simple, and while he originally designed the TinyPaddle to be a back-up option, I know a number of hams who use the TinyPaddle as their main field key.
Again, I can’t stress how cool it is to have a radio that allows you the flexibility to hit the air pretty much anywhere, anytime.
The KH1 is so quick to deploy, low-impact, and low-profile.
It’s as conspicuous as holding a transistor radio with a telescoping whip. So far (it’s still early days, let’s be honest here) no one has seen me with the KH1 and asked me if I’m a spy. I can’t count the number of times I’ve been asked this over the years of POTA activating!
It’s funny how sometimes one small accessory can have a huge impact on a field radio kit.
When I first learned about the Elecraft KH1 (basically, the day I was invited to join the volunteer testing group), I felt like Elecraft had designed my ideal QRP radio. The KH1 is super compact, weighs 13 oz completely loaded, covers my favorite bands, and has features I would expect in much pricier radios. It reminded me of my beloved KX1, but even more portable with more features.
The KH1 caters to handheld or pedestrian mobile operating–at least, that was the overarching design objective. It accomplishes this amazingly well. It’s so easy to operate handheld, and there’s nothing else quite like it on the market. I suspect that when others copy the design (I’m sure they’re already doing so–!) it won’t be as versatile, functional, and lightweight.
At the end of the day, though, I feel like I’m only using the KH1 pedestrian mobile about 30% of the time I have it on the air. Of that 30%, I’d say that only 10% of the time I’m pedestrian mobile while activating, and 20% of the time I’m doing little impromptu radio sessions in parking lots, ballparks, while visiting family, and even on my own mountain property.
While handheld operating is simply a game-changer, I knew I wouldn’t do this 100% of the time with the KH1. It’s for this reason that my very first bit of proper KH1 feedback to Elecraft, well before I had my hands on a prototype, was that a right-angle adapter for the whip antenna would truly round out the KH1’s field prowess.
This would basically give my KH1 the same functionality of my beloved KX2 and AX1 antenna combo, but in an even more portable package.
Turned out, Elecraft already had a right-angle adapter on the design board!
Fast-forward to present day…
Last week, Elecraft sent me a prototype of the right-angle adapter to test and evaluate. They’ve given it the model number KHRA1.
Full disclosure: Elecraft also gave me permission to post a video and article about this new accessory even though (at time of publishing) it’s not even showing up on their website. I will, however, link to it here as soon as Elecraft makes it available. This is an item I would otherwise have tested in private–thanks, Elecraft!
The KHRA1 is a simple adapter. Other than metal attachment hardware, most of it is lightweight and 3D-printed from a durable material (I assume the same material they use in the KH1).
Attaching it to the KH1 is very easy.
First, you unthread the large metal thumb nut from the KHRA1. You will need to hold together the remaining KHRA1 components (legs and attachment bracket) so that they don’t come apart before you attach them to the KH1. This is actually pretty easy to do, but users should know to follow the KHRA1 instruction sheet. If these parts fall apart in the field, it might require a bit of searching the ground for the pieces.
You simply thread the large thumb nut onto the KH1’s whip antenna antenna port, then thread the rest of the KHRA1 bracket/legs onto the large thumb nut.
Check out Elecraft’s illustration:
I then position the KHRA1 legs as shown above, then tighten the KHRA1 adapter so that everything is secure.
It’s super simple to do, and you can see this process in my activation video below.
Speaking of an activation…
On Saturday, March 2, 2024, (yes, only two days ago) I had my first small window of opportunity to squeeze in a POTA activation and test the KHRA1.
That day, my daughters and I had a number of errands to run, then a three-hour round-trip drive to pick up my wife. We were on a very tight schedule, but I had a 30-ish minute window of opportunity to fit in some POTA radio therapy.
I set my sights on the easiest-for-me-to-hit POTA site on the Blue Ridge Parkway: the Folk Art Center.
Amazingly, I discovered that morning, that the KHRA1 fits in my Pelican M40 Micro case along with my KH1, whip, counterpoise, key, spare N6ARA key, and earphones.
With the KHRA1, this means my M40 field kit can do both pedestrian mobile and tabletop operating. Woo hoo!
The weather that morning was simply glorious. A very wet front swept through the previous day leaving behind clear skies and warm temps. Frankly, it was a bit odd activating without wearing a jacket or hoodie.
Gear:
Note: All Amazon, CW Morse, ABR, Chelegance, eBay, and Radioddity links are affiliate links that support QRPer.com at no cost to you.
Setting up was quick and easy, even though this was my first time using the KHRA1 in the field.
I hopped on the air and started calling CQ. Once spotted (for some reason the RBN auto-spotting feature wasn’t working again), the contacts started flowing in.
I worked a total of 18 contacts in 16 minutes. It hardly gets better than that for a CW activation!
I had to call QRT after my 18th contact. Even though I had a 30-minute window to POTA, nearly 14 minutes of that was taken up with my intro and summary for the activation video.
I called QRT with a small pileup still in place. I really hate doing that, but I had a schedule to keep!
QSO Map
Here’s what this five-watt activation with a 4′ telescoping whip antenna looked like when plotted out on a QSO Map:
Activation Video
Here’s my real-time, real-life video of the entire activation. As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos.
The KH1 works amazingly well as a tabletop radio when combined with the KHRA1 adapter.
At the end of the day, the KHRA1 is a very simple piece of hardware, but it effectively transforms the KH1 from a handheld radio to a tabletop.
Of course, I’ve used the KH1 numerous times with wire antennas in a tabletop configuration (I’m a massive fan of wire antennas) but the ability to use the 4′ whip antenna and internal KH1 loading coils means that I can operate anywhere I have a surface.
Herein lies the thing I love about my KX2/AX1 pairing as well. It’s just with the KHRA1, the KH1 makes for an even smaller, lighter-weight field kit.
Any negatives? The only one I’ve come up with is that the KH1 is so lightweight that I realize I need to carry a small piece of shelf liner (something like this) to provide the KH1 with a bit more grip on a slick park table, especially those composite ones.
Again, I will update this post when Elecraft announces KHRA1 pricing and availability.
Thank you
I still can’t believe the entire kit fits in this small case. Even when I put the KHRA1 thumb screw on backwards!
Thank you for joining me on this quick little tabletop activation!
I hope you enjoyed the field report and my activation video as much as I enjoyed creating them!
Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon, and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support.
As I mentioned before, the Patreon platform connected to Vimeo make it possible for me to share videos that are not only 100% ad-free, but also downloadable for offline viewing. The Vimeo account also serves as a third backup for my video files.
The QMX by QRP Labs is a five band, multi-mode radio introduced by Hans Summers G0UPL at FDIM in 2023. The QMX is the next logical step in the radio development journey at QRP Labs, bringing together the innovative approach to FSK modes like FT8 from the QDX and the CW performance of the QCX series. This is all done in same enclosure as the QCX-Mini which is not much larger than a deck of playing cards.
The QMX is about the size of a deck of cards.
The keen observer will notice that the QMX also sports a built-in microphone which, along with associated circuitry, supports future introduction of voice modes by way of firmware update. Other notable features include SWR metering with protection as well as solid-state “PIN” diode T/R switching, plus the option for “high band” coverage of 20 through 10 meters in addition to the original 80m-20m version.
Most hams have, at one point or other, forgotten to throw the antenna switch, adjust the tuner, or even connect an antenna before transmitting. The SWR meter and protection really sets the QMX apart from earlier QRP Labs radios. There are plenty of sad tales on the QRP-Labs forums from QCX or QDX users that “smoked” the BS170 mosfet finals in a moment of operating into a badly mismatched load. It’s remarkably easy to do, ask me how I know!
The Build
Based on experience with the QCX-Mini and having put together several QDX’s, I admit to being hesitant to starting assembly of this radio. The level of integration in the QMX as a multi-band, multi-mode unit is probably the highest yet to come out of QRP Labs. The components that were merely small in earlier radios are absolutely tiny in the QMX, specifically the LPF toroidal cores. The main board, internal switching power supplies, display, and controls board are all sandwiched together in a tight fit for the custom enclosure.
Most of the electronic components installed on the main board.
The build started with a slow and methodical approach of doing a little bit each day and working in the morning when my mind was fresh and there was good light on my workbench, a.k.a. the dining room table.
The first “disaster” happened when performing the factory recommended modification to Revision 2 boards shipped in 2023. The mod calls for a protection diode to be installed across a SMD mosfet. Several leaded 1N4148 diodes were available in my “junque” box so I attempted to carefully fit one of these in the right position on the board. While soldering the diode in place I managed to lift C508, a microscopic .1uF SMD capacitor, clean off the board!
The suggested modification adding a protection diode.
Given the tools at my disposal, there was no way I was going to be able to get that capacitor back into place. Therefore, I grabbed a standard through hole .1uF cap and painstakingly got it connected in the right place, verified by lots of continuity testing.
Once finished with all the electronic components on the main board, I was feeling pretty cocky and also the completion of the project was more clearly in view. The cautious and methodical approach gave way to a faster build pace, which directly lead to the second “disaster.” While installing the headers that connect the main board to the display board, I failed to CAREFULLY READ THE ASSEMBLY MANUAL and soldered the male pin headers where I should have installed the female sockets!
This misstep might have ended the project right then and there if I had not at some point in the last year bought a proper desoldering tool. This is not an expensive automatic vacuum pump powered solder re-work stations, but rather a heating tip and manually actuated solder sucker built into one tool. Twenty-two unsoldered connections later, we were back on track. Continue reading QMX – From Kit to Field!→
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