This year’s Hamvention was truly incredible. While I haven’t seen the official attendance figures, I can only assume it was highly attended based on my observations.
Once again, my friend Mike (VE3MKX) captured a plethora of photos at Hamvention—both in the flea market and the indoor exhibit areas—and has generously shared them with us here.
Thank you, Mike!
Click to view the complete photo album–> Continue reading Mike’s 2025 Hamvention Photo Gallery
Readers, there’s a bit of a backstory to this guest post by my friend Jamie (AA4K). During the W4SOTA campout in October 2023, Jamie showed me his favorite field radio: the (tr)uSDX. I’ve used the (tr)uSDX for a couple of activations, but I’ll be honest—I haven’t exactly shown it a lot of love. I’ve even complained about its audio and receiver performance in the past. Jamie, on the other hand, really enjoys using his and makes a solid case for it as a field radio.
I asked if he’d be willing to write a guest post for QRPer, and he agreed (eventually!). When I saw him at Hamvention this year, he told me the article was ready—and in true form, he sent it to me via Winlink… using his (tr)uSDX.
by Jamie (AA4K)
There are many factors that must be considered when choosing a field radio. How big and heavy is the radio? How hard is it to repair or replace the radio if it becomes damaged or lost? How hard is the radio to operate? How power-efficient is the radio? Does the radio have the desired/required modes and features? Of course, the most fundamental question is, “Does the radio work?” I will try to answer these questions as I lay out… a case for the (tr)USDX as perhaps an almost perfect field radio.
The first question is an easy one. Aside from small home-brew radios such as K6ARK’s “Choking Hazard”, there isn’t a smaller or lighter commercially available radio out there that I am aware of. The (tr)USDX measures 112 x 61 x 50 mm (I trimmed the encoder post and used a lower profile knob), and weighs 5.3 oz, or 151 g. The next closest currently available commercial radio is perhaps the QRP Labs QMX. This radio is very comparable in size (110 x 64 x 38 mm) and cost, but it does weigh more at 7.3 oz, or 207 g. The more rugged metal case probably plays a big part in the weight difference.
The (tr)USDX is often sold as a kit for about US$86 (+$20 for the case) [QRPer affiliate links]. Any repairs should simply involve desoldering affected components and replacing, or possibly just updating the firmware. I am a relative noob when it comes to kit building and this kit is honestly not very difficult to build… about one day. The instructions and support videos provided by the hardware developer, Manuel DL2MAN, are very thorough. I learned a lot about radios from building the kit. If you have no interest in kit building, the assembled radio can currently be purchased from Amazon for US$138, complete with a case. Whether purchased as a kit, or already built, the band pass filters on the radio board will need to be tweaked to get the most out of your radio.
The (tr)USDX only has 4 buttons including the rotary encoder: Menu, Encoder, Enter, and PTT. The Menu and Encoder cover the majority of the adjustments, and most of the time I don’t use the Enter and PTT buttons. The PTT functions only as a ptt or cw key depending on the mode (yes, if your key breaks mid activation, you have a built-in backup key). The single-layer menu system is simple to scroll through, and the most commonly used items are near the front of the menu.
The most challenging aspect of operation for some people is the tiny OLED screen which gets obliterated in bright light. Reading glasses do help, although when you become familiar with the menu are not as important. I would love to see a version with an e-ink display and, more importantly, a push-button wheel rotary encoder (to remove the protruding knob).
This radio sips power. I tested the radio I built using a LiFePO4 battery that supplied 13.56v. The current draw on receive is 66.1 mA, and 570 mA on CW keydown into a dummy load. A properly tuned (tr)USDX delivers about 5w on each of the five bands when fed ~12v. A set of three 18650s in series will provide the proper voltage and power the radio through many activations.
The (tr)USDX is not for princesses. It is a minimalist’s radio. But if you start from the perspective of an ultralight backpacker who has to justify every gram in their kit, this radio checks all of the boxes. It is a five band radio (Low, Classic, and High band models available). It is capable of doing voice, cw and digital modes. Thanks to a beta update from the firmware developer, Guido PE1NNZ, this radio will interface with a computer without requiring a soundcard. One of my favorite features of the radio is the built-in SWR meter. With the SWR feature enabled in the menu, just put the radio in CW mode and press the PTT to find out if your radio is happy with the current antenna arrangement.
Although my total activation count is nowhere near as high as many of you, I have used the (tr)USDX for a majority of my successful POTA (156 as of this writing) and SOTA (72 as of this writing) activations. My confidence in this little radio was demonstrated when I used it on an ATNO activation of Admiralty Island National Monument (US-4537) in Alaska.
One reason why I like to participate in SOTA and POTA is that it gives me an opportunity to practice field radio deployment and operation with the goal of being ready to communicate anywhere and anytime. This level of readiness means that I have the necessary equipment with me all the time. For me, the (tr)USDX is my EDC (every day carry) radio. It can bounce around in my backpack (in its protective case, of course) and be ready to deploy if needed. If it were to get lost or broken, I can fix or replace it easily. And I find it to be easy enough to use with the understanding that it isn’t a luxury radio.
Click here to view on YouTube.
Click here to download the print file for Jamie’s the modified (tr)uSDX case.
If you own the popular MTR-3B V4 transceiver, you’ll be pleased to hear that a new and greatly improved manual is now available on the LNR Precision website.
If you’ve recently picked up an MTR-3B V4—or if you’ve had one for a while and want clearer documentation—I highly recommend grabbing this updated guide.
On Tuesday, May 6, 2025, I made a little time in my afternoon schedule to take my Venus SW-3B on a final POTA activation.
I might have mentioned in previous posts (and certainly on the Ham Radio Workbench) that starting in April, I’ve been trying to downsize the shack a bit. This is a process I go through at least annually. My shack/office is very small, so things pile up quickly—and I like to divest myself of gear as best I can.
During this process, one of my readers here on QRPer reached out and asked—on a whim—if I’d consider selling him my Venus SW-3B. I gave it some thought and decided to do so.
I love the SW-3B, but the truth is, I hadn’t used it in a long while. It’s been tucked away in my headrest kit for more than a year, and I just haven’t been reaching for it. That and, frankly, I’ve a couple of MTR-3B LCDs, an MTR-4B, and an MTR-3B Currahee model–I’m flush with super compact transceivers.
I agreed to sell him the SW-3B but told him I wanted to take it out on one final activation—and that’s exactly what I did!
Blue Ridge Parkway (US-3378)
I had to fit this activation into a one-hour window while my daughter was in a class. Fortunately, the class was no more than a mile from the Blue Ridge Parkway. Unfortunately, if I wanted a site with a picnic table for easy operation and setup, I wasn’t terribly close to one.
Luckily, I had my complete SOTA kit packed, including my Helinox chair and Tufteln knee board. With those two items—paired with the SW-3B—I could operate comfortably just about anywhere.
I picked a spot on the side of the road, very close to the parkway entrance from US-25. I knew the drive back to her class would take no more than three minutes.
I paired the SW-3B with my KM4CFT 30-meter end-fed half-wave, which includes a 40-meter linked extension. I figured with this antenna, I could operate on 40, 30, and 20 meters (by removing the link if necessary).
Lately, propagation has been flaky, so having a bit of frequency agility is key to a successful activation!
Note: All Amazon, CW Morse, ABR, Chelegance, Spooltenna, eBay, and Radioddity links are affiliate links that support QRPer.com at no cost to you.
I hopped on the air and started on 20 meters by calling CQ POTA.
Fortunately, 20 meters seemed to be in decent shape. Continue reading Parting Waves: My Last Activation with the Venus SW-3B
by Dave (KO4YLZ)
Like so many other SOTA activators, I’m constantly tweaking my gear to optimize it for all the variables we encounter in the mountains. One of my main antennas is, of course, an EFHW. Paired with my KX2, I generally get sub-1.6:1 SWR on 40, 20, 15, and 10. However, 30m has an unacceptably high SWR. I considered switching to a multi-link EFHW, but hopping up to change links to chase an inadvertent S2S on another band is inconvenient, especially when the link for low bands is generally well beyond my reach and requires lowering the antenna.
To fully optimize my EFHW I decided I needed to come up with a way to add a “remote” link for 30m. After a couple of design iterations, I came up with the light-weight and compact remote antenna link shown/described below. The version described here is not my final one. While this “pill bottle” version is still quite small, I’d like to reduce the size even further.
Let’s start with the end…
Here’s the final product. It weighs under 1 oz. and is ~2.5” long. I have included a complete parts list at the end of the article.
My design considerations were:
For those in a hurry, here’s a summary description of the remote antenna link. It consists of a very, very small remote control Bluetooth relay powered by two CR2032 batteries (user supplied). A set of contacts (either normally open or closed) lead from the relay to male and female 2mm bullet banana connectors in the cap of the pill bottle. Two matching bullet banana connectors at the antenna plug into the remote control link.
To operate, you simply open the bottle, switch on the batteries, re-install the cap, extend the antenna, and plug the bullet banana connectors at the antenna into the opposite pair embedded in the cap of the pill bottle. When you are ready to operate, you just push the remote button. When the remote button is pushed, the relay opens or closes thereby making or breaking the link and physically shortening or lengthening the antenna. Below is a picture of both sides of the mini-relay (antenna wire not shown)
The relay can run on 3.5-12 volts and can handle 1A. The included 1-button transmitter sends a signal (455mHz) to the relay and either opens or closes a set of contacts depending on how the user programs the relay.
I won’t bore you with a detailed written explanation…it’s a pretty simple build. Below are a simple wiring diagram and a series of photos with build details [click images to enlarge].
The relay has three operating modes: latched, momentary, and toggle. Because I wanted the 30m link to be normally connected when the relay is in standby waiting for a signal from the remote control and open and stay open when I pressed the remote button, I had to reprogram the relay. Programming is accomplished by turning the unit on, then putting a 22ga wire jumper between the two “programming dots” and then pressing the remote button until the LED on the relay board flashes the number of times specified in the instructions for the operating mode you want. The instructions are not very clear, so I recommend connecting the unit to your VOM in continuity mode to figure out the button/LED flashing sequence that corresponds to how you want the relay to behave.
The unit is rated for 1A so, to be sure I wasn’t going to blow it up when I transmitted with 10 watts, I used ChatGPT to produce a very nice graph showing the current at the 30m position on the antenna for each band when transmitting with 10W. Here’s the graph. Luckily, the maximum current at the 30m position (~43’) is .6A at 7.062 MHz.
I tested the unit on my KX2 by setting my operating frequency and then putting the KX2 tuner in bypass mode and pressing the button on the remote control; Ding…the SWR jumped immediately to the expected pre-determined (and acceptable) SWR value for the 30m band!
The unit draws 7mA when in standby and 32mA when the relay is energized. Assuming 40 minutes of operating off of the 30m band (relay not energized) and 20 minutes on the 30m band (relay energized), I calculated that approximately 17mA would be drawn from the two CR2032 batteries. Given that a CR2032 battery has a capacity of 220mAh, they should provide about 12 hours of operation.
Any questions, please comment.
Dave – KO4YLZ
Parts List
Note: The Amazon links above are affiliate links that supports QRPer.com at no cost to you.
Just a quick note: ABR Industries—known for their high-quality, US-made coaxial cable assemblies—is running a 20% off site-wide sale now through Monday, June 2nd.
Here are links to some of my favorite ABR cable assemblies:
We’re proud to be an affiliate of ABR, so any purchase you make using our links also supports QRPer.com. Thanks as always for your support!
by Vince (VE6LK)
As always there are lots of links within the article. Click one! Click them all! Learn all the things! ?
Dear readers, Hamvention 2025 was a wonderful getaway for me, and I met so many people in 3-D that I’d only ever worked with over teleconferencing. It was super great to see members of the Ham Radio Workbench Podcast crew (and friends of…) and get to hang with them for several days. Naturally, this included QRPer.com host Thomas K4SWL.
I was the last of the group to leave the Dayton area on May 20th and I began my drive back to the Indianapolis airport for the first of two flights home. And, naturally, this means a POTA stop along the way, and it would be my first in Indiana. While I had grand plans to visit WV and KY along the way, those plans fell by the wayside for a simpler and direct route from Dayton to Indianapolis.
When I travel like this, I look for parks that appear to be radio quiet and are not too far off the path of travel. Fort Harrison State Park was my chosen destination. And it did not disappoint in any way at all. Located in the NW corner of the Greater Indianapolis area, it is 1,700 acres of recreation nestled in a small quiet valley just away from the hustle and bustle of everyday life. Homes outside the park entrance seem to be from an era of yesteryear. I wished I would have had more time to explore!
Arriving at the park and one of the many picnic areas, I chose to be beside the lake. It was raining quite hard until up when I arrived and then let up to an intermittent drizzle. Fortunately there was a picnic shelter and a washroom building within eyesight. Accordingly I set up in the shelter with my KX3, Charmast battery and VK3IL pressure paddle.
I put out my Gigaparts Explorer 20 mast and new-to-me Packtenna 20m EFHW along with my fishing rod holder ground spike, hit tune on the KX3 and got to work.
The contacts didn’t come fast and furious, as the past week or so the SSN, SFI, A and K indicies weren’t really in my favour. Many times I would answer a station and they’d simply disappear. It took 30 minutes on air to complete the activation. This was a stark improvement from the day prior where it took well over an hour.
The Reverse Beacon Network told me my 10W signal was being heard all over the USA and some in Alberta Canada also, despite it putting my outgoing dot (see image above) on Montana where my USA callsign is based.
Still, after the extreme hustle and bustle of the days prior, this was super relaxing and just the break I needed before dealing with airports, rental cars and plenty of other travellers.
Having spent so much time around K4SWL, I channelled his video style and did an end to end on the activation without any edits – you can see that video on YT.
Click here to view on YouTube.
Sometimes it’s just great to find a place to hang out in the peace and quiet, and this park was perfect and just what I needed after many days of constantly running.
72 and dit dit,
…Vince
First introduced to the magic of radio by a family member in 1969, Vince has been active in the hobby since 2002. He is an Accredited examiner in Canada and the USA, operates on almost all of the modes, and is continually working on making his CW proficiency suck less. He participates in public service events around Western Canada and is active on the air while glamping, mobile, at home or doing a POTA activation. You can hear him on the Ham Radio Workbench podcast, follow him on Twitter @VE6LK, check out his YouTube channel, and view the projects and articles on his website.
It’s hard to believe that Four Days in May (FDIM) 2025 has already come and gone—and even harder to believe that attendance was even larger than last year!
What an amazing event.
As always, FDIM is my favorite part of the Dayton Hamvention weekend. If you’re a QRPer and haven’t made it to FDIM yet, I can’t recommend it enough—this gathering is pure QRP energy from start to finish.
I truly enjoyed meeting so many QRPer readers and supporters in person. Thank you for stopping by and sharing your stories—it was an absolute highlight for me!
Once again, I was so busy chatting and connecting that I barely had time to snap any photos. Thankfully, my friend Mike (VE3MKX) came to the rescue with another fantastic gallery.
Thank you, Mike!
Click to view the entire photo album–> Continue reading Mike’s 2025 Four Days In May (FDIM) Photo Gallery
Jonathan KM4CFT reached out to me recently to inquire if I was interested in trying his CFT1 QRP transceiver. The inquiry both surprised and delighted me as I’ve never had such an opportunity.
I nearly said no because I am no antenna expert and, as this rig has no internal antenna tuner, I’d need to learn more about antennas, SWR, and resonance.
My limited antenna experience dates back to when I first entered the hobby. I had ZERO antennas and no idea where to start. An acquaintance suggested I make a home-brew linked dipole and gave me a few pointers in doing so. I vividly remember limping through learning how to trim an antenna. That project taught me that I want as low a SWR as possible and to cut the antenna for the portion of the band on which I want to operate.
Those of you who read my articles here on QRPer know that I use an Elecraft KX2 for my field operations. I’m very happy with this radio and love that it has an internal antenna tuner. But the CTF1 does not. Here is where my hesitation and trepidation at trying this unit entered the picture. I figured the antennas I use on a regular basis might not play nice with the CFT1 and hence my reluctance to say “yes” to this opportunity.
But this is ham radio, right? In ham radio, we relish challenges because they are opportunities to learn. This was my opportunity to learn not only about antennas in general but also to be more thoughtful as to how I deploy them in the field. This was an opportunity for growth.
I dug out the RigExpert Stick antenna analyzer I purchased nearly three years ago and tested each of the antennas I currently have, just for jollies. I understand that many factors impact SWR – height of the antenna, coax length, proximity of other objects, etc. For the purpose of this exercise, I just wanted a ball park idea as to what antennas I could or could not use with this rig without a tuner.
I found both the home-brew linked dipole and the Chelegance MC-750 would work fine. Out were the EFRW and AX1. As I’d been hankering for an EFHW in my kit, I purchased the Sparkplug EFHW and trimmed it. These kinds of projects intimidate me because I do not have much experience with them; however, one cannot learn what one does not attempt.
I used the CFT1 on three activations: April 25th at the Savannah National Wildlife Refuge (NWR) (US-0522) with the Chelegance MC-750, April 30th at the refuge again but this time with the Sparkplug EFHW, and Thursday, May 1st at George L. Smith State Park (US-2179) with the Chelegance again.
It was a warm day at the refuge on April 25th. I selected an open area in which I had set up in the past. There were wild blackberries growing directly under the oaks in the shade. The view was lovely and, when not engaged with the activation, the red-wing blackbirds, coots, and other birds kept me entertained. Unfortunately for me, the sun moved out behind the oak trees not long after I arrived and I soon called QRT to avoid being baked.
I was pleased with the QSO map for this activation – 27 contacts on 40, 20, and 17 meters over the course of an hour and a half.
My second experience with the CFT1 was on April 30th, again at the Savannah NWR, however, this time using the Sparkplug EFHW. I found a different spot, one I passed up before but was usable today as it was freshly mowed. There were wonderful, tall oak trees at this location which afforded shade and high, unencumbered branches for installing an antenna aloft. Continue reading The POTA Babe Tries the CFT1
Good morning, QRPers!
Day two of Hamvention 2025 was absolutely amazing—and the weather couldn’t have been more ideal. I wish I had time this morning to write a proper recap, but I’m grabbing a quick breakfast and heading back to the Greene County Fairgrounds for day three.
That said, I wanted to drop a quick note and share a photo of a little surprise from the Flea Market…
Even though I told myself I wouldn’t buy another radio at Hamvention, I spotted one I simply couldn’t pass up:
I already own a TR-35 (a rig I absolutely love), so I let that one go. But I didn’t have an MTR-4B in my collection… and that red chassis in the early morning sunlight? Irresistible. The asking price was $200—very fair, in my opinion—so I snagged it.
Later that day, I showed it off to my good friend Joshua (N5FY), and wouldn’t you know it—he gifted me one of his MTR-4B protective covers!
As soon as I got back to the hotel room that evening, I installed it.
She’s ready for the field.
I’ve actually wrote a review of an MTR-4B I borrowed from a reader. You can check out that review with links to field report here. I’m looking forward to taking this little red machine out to a summit soon!
More to come after Hamvention wraps up.
Thanks again to everyone who’s stopped by to say hello—it’s truly been the highlight of my weekend!
— Thomas (K4SWL)
