What is it about winter that engages my inner kit-builder–?
I go through this cycle every year: when outdoor temps plummet, I fire up the soldering iron and start building kits that have been sitting on the shelf for the previous three seasons.
I used to think that I built more kits in the winter because I spent more time indoors, but that’s not actually true. Reality is, I probably spend more time outdoors in the winter than I do in the other seasons…save fall, perhaps.
I actually have a QCX+ transceiver kit that a kind reader generously donated to me (thanks again, OM!). I can’t wait to dig into this particular build, but I’m forcing myself to wait.
Until I finish building and installing my Murphy Bench (check out this HRWB podcast episode where we take a deep-dive) I don’t have a dedicated space for a good multi-day transceiver kit. At present, I have to take over the dining room table and as you might imagine, the others in my family aren’t incredibly pleased with a semi-permanent workbench in the middle of the house.
I’m making my Murphy Bench a priority and dangling the QCX+ as a reward for completing the build. Wish me luck!
I’m curious: Do you find that you also do more kit-building during certain seasons? What kits or other projects are on your horizon?Please comment!
K-1716, Silver Sands State Park, Milford, Connecticut
January 13, 2023
By: Conrad Trautmann, N2YCH
A digital mode multiband transceiver for $69? Yes! QRP Labs has the QDX kit available for $69 US. Add $20 if you would like a very nice black anodized aluminum case to mount it in and if you want it assembled and tested add another $45. Visit the QRP Labs web site for all of the details (QDX 4-band 5W Digi transceiver (qrp-labs.com)
How well can a $69 digital transceiver work? Read on…
I ordered my QDX kit back in May 2022. It arrived in June, I assembled it and ran some tests at home. It worked well on FT8 into my home antennas. It interfaces nicely with WSJT-X and I liked the idea of using a low power transceiver to band hop on WSPR. My QDX is an early four band version, which does 20, 30, 40 & 80 meters. I set it to band hop on all four bands not remembering that my multiband offset center fed dipole is not resonant on 30 meters. Since the QDX does not have a tuner, it didn’t like the higher reflected power of a two minute long WSPR transmission into a bad load and smoke resulted. I was fortunate that the failure was isolated to the RF power amplifier transistors and replacing those got me running again. This was my own fault, not the transceiver. Now, it band hops on 20, 40 and 80 meters with no issues, I eliminated 30 meters from the hop schedule.
I share this important story at the beginning of my field report as a warning to anyone considering using a QDX to be very careful when connecting an antenna to it. Since the QDX does not have an internal antenna tuner, you either need a resonant antenna or must use an external tuner to provide a 50 ohm load with low SWR to the QDX. The QRP Labs groups.io site has a number of posts from users with different tuner suggestions.
Now comes the fun part. I visited Silver Sands State Park, K-1716, located on Long Island sound in Milford, CT on January 13, 2023 in the afternoon. While it was Friday the 13th, I had nothing but good luck. Knowing I would be running QRP power, I decided to use what I consider to be my best 20 meter antenna. It’s a modified version of a Buddipole, which I call my “no coil” Buddipole dipole. I use a Buddipole VersaTee mounted to a WILL-BURT Hurry Up mast, which is a push up mast that extends to about 25’ high. The dipole consists of two Buddipole 32” accessory arms, one for each side of the VersaTee and two MFJ 17’ telescoping whips, extended to just about 17.5’. This provides a very broad bandwidth and low SWR on 20 meters. See the screen shot of my antenna sweep from the RigExpert analyzer below.
Here’s a photo of the antenna in the air.
The temperature on this January day was a mild 55 degrees so I was able to set up my equipment in the back of my Jeep. Here’s everything I needed to do the activation. Since the antenna is resonant, I did not use a tuner.
My iPhone gives you an idea of just how big the QDX is, which is sitting just to the right of it. There are only three connections needed, the antenna cable, a 12V power cable and the USB cable. I was using my Bioenno 9ah battery for power. I brought the Bird Model 43 with a 25 watt element in it to monitor the output power and also to measure the reflected power, which barely even nudged the meter. It was effectively zero watts reflected. In the photo above, I was in a transmit cycle and you can see the power meter just a touch above 5 watts. On the computer, you can see a mini pile-up of six hunters in the queue. One thing to note about the QDX is that you can’t adjust the power by lowering the PWR slider in WSJT-X. It’s recommended to leave that at maximum. The way to adjust output power is to adjust the power supply voltage. In this case, the Bioenno had a full charge, so the radio was running full power.
I began the activation without spotting myself, just to see who’d hear me. Here’s a map of the pskreporter showing my spots.
I eventually spotted myself so hunters would know what park I was at. I was amazed that during my activation, I never ran dry or had to call CQ POTA, there was a steady stream of hunters the entire time. The QDX does a fine job receiving, here’s a screenshot of WSJT-X including the waterfall to show what it was receiving.
So, how did the $69 radio do? In a one hour and 17 minute activation, I completed 46 FT8 QSO’s. Here’s my coverage map.
I managed to complete three park to park QSO’s, too. One park called me and I called the other two who heard me and answered. I use JTAlert which helps me keep track of the order of who called. I always try to answer the hunters in the order they called me. I’ve set up a Directed CQ alert in JTAlert for anyone calling “CQ POTA” which helps me to see who else is at a park while I’m activating. If I’m able to contact them, I use the POTA spot list to include their park number in the SIG_INFO field of my log, which is N3FJP. N3FJP is handy to use since I start a new log for each activation and I’ve configured it to upload to LOTW and QRZ when I’m done for the day.
Another thing worth noting is that there is no speaker on the QDX. I’m one of those digital operators who actually listens to the cycles while I’m on the air. It provides a certain cadence to hear each cycle go by so you know what to be looking at or clicking on and when. With no sound coming out of the QDX, it forces you to find that cadence by looking at the computer screen. For me, it means watching the receive audio levels and the progress bar to see if I’m transmitting or receiving. The QDX does have a single red LED on the front panel that will flash during transmit cycles, which is also a helpful indicator.
I’d say the results shown here speak for themselves. I had a steady stream of hunters, I had just one or two QSO’s that needed a second RR73 to confirm and the coverage was as good as most activations I’ve done with more expensive radios and more power. Despite the self-inflicted hiccup I experienced at the beginning, I’d say that If you’re looking to try activating digital for Parks On The Air or even for your home, the QDX certainly works very well and provides a lot of value for the money.
As I mentioned yesterday, I’ve had the pleasure of helping John beta test this radio for the past month. In that time, I’ve gotten to know the radio from the inside out and have even taken it on a few POTA activations. In fact, with John’s permission, I just posted my first TR-45L activation video for Patreon supporters yesterday. The radio was using an early firmware version in that video.
TR-45L Video Tour and Overview
Yesterday, after an early morning appointment, my schedule opened up; a rarity in my world.
I then got the idea to take the TR-45L out to a park, do a full video overview of its features, then put it on the air in a POTA activation.
Hazel loved this idea too.
So I packed the TR-45L, a log book, my throw line, and two 28′ lengths of wire. Hazel jumped in the car before I could invite her.
I’ve used a wide variety of antennas on the TR-45L over the past weeks, but I hadn’t yet performed a park activation only using two lengths of wire and relying on the TR-45L’s optional Z-Match manual antenna tuner. This would make for a great real-life test!
I pushed this video to the front of the line since the TR-45L just hit the market. I wanted to give potential buyers an opportunity to see and hear this radio in real world conditions thinking it might help them with their purchase decision.
I’m currently about 7 weeks behind publishing my activation videos. Much of this has to do with my travel schedule, free time to write up the reports, and availability of bandwidth to do the video uploads (I’ve mentioned that the Internet service at the QTH is almost dial-up speed).
I was able to publish this video within one day using a new (limited bandwidth) 4G mobile hotspot. Patreon supporters have made it possible for me to subscribe to this hotspot service and I am most grateful. Thank you!
So that I can publish this report quickly (this AM), I’m not going to produce a long-format article like I typically do. Instead, this is one of those rare times when the video will have much more information about the radio and the activation than my report. I’ve linked to and embedded the video below.
Good morning Thomas, from wintry southwestern Ontario.
I thought I would send you a quick message to share my experiences, so far, with the little TR-35.
Yesterday, around 3pm, I took the above unassembled kit off the shelf and began to melt solder. The smoke test was successfully performed the next morning at 1:30am, after non-stop building (with the exception of a few hours for eating and catching up on a little tv). I measure twice and solder once hihi.
I had my calendar marked for February 15 to check the site again for the 3rd batch as I thought that was the day they planned to issue another pre-order.
My buddy Eric (WD8RIF), who is the President of the Athens County Amateur Radio Club (ACARA), contacted me yesterday asking if I knew of any QRP kits designed with phone/SSB operation in mind. One of ACARA’s members was searching for one.
The only other kit I could think of was the new (tr)uSDX. When Eric asked for a link to the product, I went to the Rowaves site and discovered that they were taking pre-orders for the third wave of kits. Like, right then and there!
Without hesitation, I added one to my shopping cart and checked out.
I thought perhaps Rowaves caught up and no longer had a waiting list. This morning, when I checked the site again however, it appears they’ve sold out of the third batch.
Without Eric’s prompting, I would have never thought to check the Rowaves site yesterday.
Side note:There are various (tr)uSDX group buys out there. I don’t completely understand how they work, but perhaps someone with more experience can comment. DL2MAN has information and links on his webpage.
If I’m being brutally honest, the (tr)uSDX kit is a bit intimidating for me. I recently referred to myself as a “gross motor skills” kit builder. I think that’s a pretty accurate description. I’m fine with through holes, simple toroids, and very clear, illustrated instructions. Truth is, I absolutely love building kits. But I’m not an electronics engineer, so when instructions are vague, I can get lost quite easily.
The (tr)uSDX toroids don’t look terribly complicated and all of the surface mount components are pre-installed. Still: it’s a wee kit and I’ve yet to check out the build instructions.
I recently finished my Phaser digital mode QRP transceiver kit and have had a hankerin’ to take it portable, and today was the day.
Temps were in the upper 60s with clear blue sky. About fifteen minutes from home is the Watauga Point Recreation Area on Watauga Lake in Carter County, Tennessee. It’s a day use area and is not an official POTA site, though it is in the Cherokee National Forest, which is. I opted to not make this a POTA activation as it was more of a first time “proof of concept” trip.
The Phaser is a small digital mode transceiver designed by Dave Benson, K1SWL with the enclosure the design of AA0ZZ, Craig Johnson. Phasers were available for most all of the HF bands, put out between 3 to 5 watts, and in addition to FT8, have the ability to program a second frequency to operation other digital modes such as PSK-31. They were sold and supported through Midnight Design Solutions, but unfortunately are no longer being offered. Occasionally I see them coming up for sale on the QRZ.com swapmeet forum.
In addition to the Phaser, I brought an FT-891, an LDG Z-11Pro 2 tuner, a netbook computer, and two batteries; a small AGM for the Phaser and a deep cycle lead acid power pack for the FT-891. I brought my W2LI magnetic loop antenna and a homebrew “NorCal Doublet” that sets up as an inverted V on a 20 ft kite pole as a backup antenna. The whole kit (excluding the batteries) fits in two wooden ammunition crates which make it really easy to drive, set up, and operate.
One note on using the W2LI mag loop. You need to first tune the antenna using the radio and listen for an increase in the background noise level. Using the Phaser while connected to my computer made that not possible. If I had brought a small set of earphones I could have plugged them into the audio out jack on the Phaser and tuned for max background noise. So, instead I connected FT-891 to the loop and used it to tune the antenna to 30 meters. Next time bring earphones.
After about fifteen minutes I had the station set up. The waterfall on WJST-X showed that the Phaser was receiving transmissions but no displayed text. Unfortunately I had neglected to synchronize the computer clock before I left the house. The netbook is pretty old and the internal battery needs to be replaced. What to do? First I tried to manually sync the clock to WWV but Windows 10 won’t let you set the seconds in the clock to 00. As I had cell service I figured I could use my cell phone as a hotspot. Never having set it up before I have to say that it was pretty easy. Thank you 21st century tech! This allowed me to sync the internal netbook clock, but it also let me log contacts on QRZ.com, and check my propagation on PSK Reporter.
The Phaser puts out around 3.5 watts, so I didn’t respond to a CQ that was less than -5 dB. While PSK Reporter showed reception of my signal up and down the East coast, contacts were scarce. I seemed to have a window open up into New England as I worked PA, MA, and CT. I was right in the middle of my fifth contact when the computer battery died so that was it. WSJT-X reported these stations on the +dB side for reception but my signal strength was always reported at < -10 dB.
The 30 Meter band was up and down with band conditions being reported as only Fair on the Solar-Terrestrial Data report on QRZ, and at one point for about a half hour there were no signals displayed on the waterfall.
With a loop antenna on a tripod and 3.5 watts I can’t complain. I’m thinking of building an RF amplifier to boost the output up to 10 watts which should help. My next step is to load WSJT-X on my tablet and see how portable of a kit I can assemble. As FT8 was designed as a weak signal mode, it’s perfect for QRP portable operating.
Many thanks to Pete (WB9FLW) who shares the following information about the new QDX transceiver from QRP Labs:
The “QDX” (QRP Labs Digital Xcvr): a feature-packed, high performance, four-band (80, 40, 30, 20m) 5W Digi-modes transceiver kit, including embedded SDR receiver, 24-bit 48 ksps USB sound card, CAT control, synthesized VFO with TCXO reference. QDX transmits a SINGLE SIGNAL, it is not an SSB modulator with associated unwanted sideband and residual carrier, or intermodulation due to amplifier non-linearity. QDX outputs a pure single signal.
The Optional enclosure is black anodized extruded aluminium, very sturdy and elegant. The enclosure size is 89 x 63 x 25mm without protrusions. The front and rear panels are drilled and cut to match the QDX PCB with laser-etched lettering. The enclosure includes four self-adhesive feet.
List of features:
Four bands 80, 40, 30 and 20m
5W output at 9V supply (can be built for 4-5W at 12-13V supply)
Single signal transmission (zero unwanted sideband, zero residual carrier, zero intermodulation distortion)
Solid-state band switching and transmit/receive switching under CAT control
High performance embedded SDR SSB receiver with 60-70dB of unwanted sideband cancellation
Built-in 24-bit 48ksps USB sound card
Built-in USB Virtual COM Serial port for CAT control
Si5351A Synthesized VFO with 25MHz TCXO as standard
Easy to build single-board design, Professional quality double-sided, through-hole plated, silk-screen printed PCBs
All SMD components factory assembled
Connectors: 2.1mm power barrel connector, USB B (for audio and CAT control), BNC RF input/output
Built-in test signal generator and testing tools
Receive current 100mA, Transmit current 1.0-1.1A for 5W output with 9V supply (around 0.7A for 5W with 13V supply).
Optional aluminium extruded cut/drilled/laser-etched black anodized enclosure
Absolutely amazing! I’m not sure how Hans is able to innovate at the pace he does, but I think we’re all better for it. This will be a big seller for those who’ve been looking for a high performance QRP digital mode transceiver.
I have been a fan of QRP operating since I got licensed in 1983. The sticker in the picture is a joke a good friend who is not into CW or QRP, so I include it in my field pictures.
My interest in ham radio had reached a point I was getting away from the hobby. In 2020, I learned about Parks on the Air (POTA) and Summits on the Air (SOTA). I got hooked on activating parks and summits, and now I mostly do QRP CW, much like Thomas Witherspoon, K4SWL does.
Over the past year, I’ve been refining my antennas and radios in the field. I have different radios and antennas for different reasons, and to just mix it up a bit. Occasionally, I will take my IC-7100 or IC-7300 out into the field with my Bioenno 20aH battery, if I’m not planning to hike or go far from the parking lot, or if the bands are just not cooperating.
Back in November 2020 I had my left knee replaced so I had lots of down time and made an important purchase for field activities – an IC-705. It is fantastic and does everything I want it to do without a lot of wires. I’ve also owned and sold within the past 18 months a Yaesu FT-891 (which I sold when I got the IC-705) and had both the Xiegu G90 and X5105. I would expect one day to get another FT-891 as it has amazing filtering and pulls in weak CW signals better than any radio I’ve owned. The G90 and X5105 are okay, however I was not impressed with the G90 from the start for out in the field. There were just too many wires in order to set up and use with my portable laptop computer if I was taking that along.
The X5105, which I had high expectations for, disappointed me in the fact that storing and using CW memory keying is not user friendly. The nice thing about that radio is, no microphone, no problem, I had some success using the 5105 and got great audio reports.
I’ve been looking ahead to my projected retirement and hopes of through hiking the Appalachian Trail in 2026. Although the IC-705 is an excellent field radio, all mode, VHF/UHF/D-Star/HF/6 meters, I already know for a 7 month hike from Georgia to Maine, it will just be too bulky in my backpack. I have heard really good things about the QCX-mini, however I’m an appliance operator and not good with kit building and soldering.
I saw there are options to purchase an assembled QCX-mini, so I decided to check out a 40 meter radio. It took about 2-1/2 weeks before it arrived at my QTH on Saturday afternoon. I hooked it up to one of my HF antennas in my yard used for my IC-7300 that was resonant on 40 meters. I had to use my Heil headset in order to hear the audio, plugged into the 3.5 mm jack. I used my CWMorse paddle and tuned around the band. I called CQ several times before finally I heard WA0USA in Palm Beach, FL calling CQ. I called him and got a 579 report and he was a solid 599. We chatted for about 10 minutes, and he was running a kW while I was using 5 watts. It felt good to know that I was being heard.
Sunday morning I had time to go activate a local park (K-1418) before some afternoon commitments. I had also recently purchased a link dipole for 20/30/40 meters off eBay from N9SAB. I had tested this antenna out a couple of times last week, so I wanted to pair it with the QCX-mini. I went with little expectations about the little mini, so I also packed my IC 705 just in case I needed it to complete my 10 contacts to have a successful activation. To my surprise, I spotted myself on the POTA page, and in 45 minutes I had a total of 26 QSOs in my HAMRS log! It was amazing and I think I found the perfect combination for true lightweight, portable operations.
I was so impressed with this activation that last night I ordered the 20 meter QCX-mini! These can be ordered from qrp-labs.com and they have a lot of other kits available as well. The kit itself is $55, and I opted to have it assembled ($45) and purchased the enclosure ($20).
This little radio is very user-friendly. I was able to easily access the menus, customize it to my liking, including the paddle, preset frequencies, several stored CW memories, and was on the air calling CQ Saturday evening without seeking out the instructions.
I had mentioned previously about my disappointment with the Xiegu X5105 and not being able to easily store and recall memories. Not a problem at all with this little radio. I enabled the decoder feature just to test it out, and it decodes better than the G90 or X5105, including very weak signals. The size is a fraction of the size of the X5105 and total weight for everything, including the Bioenno 12v 3aH battery is less than 2 pounds and it all stores very nice.
These quick videos were taken this evening before storms hit; that’s why you will hear lawnmowers in the background. I wanted to first show a demo of the receive decoder and how well it decodes even weaker signals:
My biggest complaint about the X5105 was how the memory was next to impossible to use. I do a quick demo how to access a stored message and send it over the air. I also have it set to repeat every 6 seconds:
I did make a couple of changes to the radio setup. I did not like having to use the headset, so I went on Amazon and purchased a mini portable 3 watt mobile phone speaker line-in speaker with 3.5mm audio interface (affiliate link). That cost under $15 and works extremely well. It has a built in charger that plugs into a micro-USB to charge the battery when not in use. I also have a cell phone holder that fits perfectly on my Neewer stand I purchased several months ago for my IC 705, and it sits nice and firm on the table. I may not take that to the field if I’m doing a lot of hiking.
Here are some other details about the QCX-mini from their website:
The Optional enclosure is black anodized extruded aluminium, very sturdy and elegant. The enclosure size is 95 x 63 x 25mm without protrusions. The top and side panels are drilled and cut to match the QCX-mini with laser-etched lettering. The enclosure includes four self-adhesive feet.
Special portable-friendly features:
Small size: 95 x 63 x 25mm enclosure (plus protusions)
Low current consumption (for example 58mA receive current, with 12V supply and display backlight off)
Low weight, 202 grams
Sturdy extruded aluminium enclousre
All-metal BNC short connector, bolted to enclosure
List of features:
Easy to build, two-board design, board with main circuit and connectors, display panel board with LCD; all-controls board-mounted on a press-out sub-board. No wiring, all controls and connectors are board-mounted
Professional quality double-sided, through-hole plated, silk-screen printed PCBs
Choice of single band, 80, 60, 40, 30, 20 or 17m
Approximately 3-5W CW output (depending on supply voltage)
High performance receiver with at least 50dB of unwanted sideband cancellation
200Hz CW filter with no ringing
Si5351A Synthesized VFO with rotary encoder tuning
16 x 2 yellow/green LCD screen
Iambic keyer or straight key option included in the firmware
Simple Digital Signal Processing assisted CW decoder, displayed real-time on-screen
On-screen real time clock (not battery backed up)
Full or semi QSK operation using fast solid-state transmit/receive switching
Frequency presets, VFO A/B Split operation, RIT, configurable CW Offset
Configurable sidetone frequency and volume
Connectors: 2.1mm power barrel connector, 3.5mm keyer jack, 3.5mm stereo earphone jack, 3.5mm stereo jack for PTT, 3.5mm stereo jack for CAT control, BNC RF output
Built-in test signal generator and alignment tools to complete simple set-up adjustments
Built-in test equipment: voltmeter, RF power meter, frequency counter, signal generator
Beacon mode, supporting automatic CW, FSKCW or WSPR operation
GPS interface for reference frequency calibration and time-keeping (for WSPR beacon)
CAT control interface
Optional 50W PA kit
Optional aluminium extruded cut/drilled/laser-etched black anodized enclosure
Just a quick note on the link dipole. It is well made and I had a 1:1 SWR on the CW part of the band, which is perfect. I did put the IC 705 to work when I attempted to work a couple of SSB stations on POTA, and at 7.235 the SWR was only about 1.3:1, so minimal loss. Check out the N9SAB antennas on his eBay site. His shipping is very quick. I took a picture of the balun with the included choke in the package I purchased, and the second picture is the link between the 20 and 40 meters. It works great.
I mentioned my goal about hiking the Appalachian Trail in 2026. I’m sure there will be other multi band mini size radios available by then and I’m hopeful QCX will have one in 5 years for me to use. My goal is to activate summits along the way while taking breaks from the hiking, or at night before calling it an evening. Since I’ll be on the A.T. I’ll also have lots of opportunity to activate POTA as well. Most thru hikers are not hams and they are always concerned about no cell phone coverage. I won’t have that issue and I’m confident I’ll be able to be in touch with other hams throughout the journey.
Thank you once again Tom for allowing me to post on QRPer. I think I finally have a QRP radio that you have not tested or purchased yet. I hope your readers find this short article useful.
Scott – KN3A
Scott Lithgow (KN3A) is a regular contributor on QRPer.com. Click here to check out his previous posts.