Comparing QRP Transceivers On-Air 

I think only my grandmother would be more gracious with the S reports… but THIS type of real world testing is SO helpful! Thank you.

What amazes me is how Guido was able to trick the SI5351 and Hans' key shaping circuit into producing SSB at all! This is the first time I've heard received audio from that effort. Thanks for posting this. It was _very_ interesting.

Great QRP devices. Props for supporting Manuel team because he is dealing with lot of crap lately. 73 and thanks for effort!

Thanks for the video. I wondered how the compared and sounded. Now I know. Keep up the great videos.

Star Wars has nothing on that first test.... it was clear, very audible before the power drop, but sounded like an intercepted message between Vader and Emperor Palpatine... i was waiting for you to say "What is thy bidding, my master?" despite this nostalgic moment, this was a great test of all three rigs, and I went into this completely ignorant of what QRP even is or means, you have slaughtered my ignorance!!! This was a good demo.... people can talk about whatever they want to talk about, but nothing shows you the money like a real, live, demo! Well done, good Sir, well done!!!

Nice comparison Video Mr Walt. Amazing to see with just 1w ssb you were able to reach 1000 miles. Nice collection. 👍🏻

An example of a USEFUL and well-done video!

Thank you for the great comparison video! It was very well done and was much needed to determine which of the cheap QRP rigs is best! 73, N7JSX

Great job, Walt. I enjoyed it. For sure Kevin does well also. I watch his RU-vid channel....with qrp and all the crazy farm antennas.

Again, an encyclopedia of information. I have purchased the tr USDX and going to try it on the beach next week. Thanks again for the Facebook links. I have managed to stay away from Facebook, but I am going to give it a try. Without your channel, none of this would have been possible, plus I would have a few more dollars in my wallet!

Thanks for the great QRP transceiver comparison. I've been very interested in the QRP Labs QDX because my primary interest is digital modes, particularly JS8, but the ability to use voice could be very useful. I've been looking into the (tr)uSDX. I love the open source development and the portability for ultralight and compact field comms. I'd probably run an end fed dipole, and mostly operate on 40m.

Such a great comparison! Thx!

Thanks Walt. Good information.

that was so cool first test

Very Kool review Kevin, Walt!! 👍👍👍

Enjoyed the comparison

You've demonstrated something I learned years ago: it's unusual for other hams to give you accurate reports of audio quality. If they can hear you, you're broadcast quality. Some years ago I was trying to build a headset to go with my VHF handheld. (This was before PC headsets were a thing, and I didn't want a big Heil headset.) Once I got it built I asked my buddy to meet me on simplex to tell me how it sounded. He claimed it was perfect, not muffled, not overdriven, very clear. I thanked him and went on my way. A few days later I discovered I hadn't even soldered any wires to the mic element. If my buddy had heard me, it's because the mic in the radio on my belt was picking me up. After that whenever I needed a radio check I'd give it to my buddy and have HIM talk on it so I could listen.

Great video!

Hey Walt.. Thanks for joining the net on Friday night.. I am just as interested in hearing about those radios so it was a great experience for me too.. Thanks for making all those purchases to make the comparisons.. I'm still deciding which one I want to purchase and your videos are an excellent resource for making my decision.. I did notice your audio sounded a little off frequency, but I guess I kind of expect that type of quality from such a low $$ radio. It wasn't something that bothered me and heck, some folks go off freq on purpose, LOL... I guess in my little "QRP SSB world" the two things I look at are, can I hear the audio and can I understand it.. if you meet those two objectives, You're Golden ! !, LOL... Thanks for doing all the hard work of video production and editing to make such great videos.. Awesome Job, keep it up... Kevin ~ k0klb

Great video, Walt. Nice to hear all three radios in the same conditions. To my ears, your transmitted audio was best (by a fair margin) on the RS-978 despite being a little off frequency. I'm sure that can be dialled out in the many menus on that radio. The truSDX was pretty decent too. The uSDX, while being on-frequency, sounded like it had RF issues on its audio and was scratchy and grainy compared to the others. I've heard a few of those on the air and they have sounded similar. At the end of the day, all three radios made the trip which was pretty impressive. Hope to catch you on the air at some point during your travels.

Very good comparison i was impressed with your 1 watt SSB i mainly 1w cw 73s Walt and Kevin de EI5EN.

Kevin K0KLB rocks the ad-hoc antennas on QRP!

Tks Mr Walt fer very nice comparison, so the USDX its better in audio then the other´s. Pretty cool to see transmitting with 0,5 watts and the signal 345, amazing. I´ve made a contact in my attic with a home brew Magnetic loop in QRP 10 watts, and contact a station from USA. that´s amazing into the attic.

Thanks for the compare

Great video!! Answers a lot of questions for us hams considering qRP.. I do wish you had tried CW as well...73/K6SDW

Just discovered this video on June 1st 2024, very good material, I'll be looking at these radios thanks again Walt de WO8USA🇺🇸🇺🇸🇺🇸

I'm a new ham. KF0KDE in Waterloo, Iowa. I grew up in Virgina Beach. To think, i can call home on 1W. I almost wanna cry.

Very good job. One of the few videos the TX audio from the own device can be heard clearly. Most reviews only show a person talking into the TRX and listening to the other station, so there is no way to get an impression of the TX audio from the own device. In this video it is different, so I like it much. Thanks for sharing.

I just got my (Tr)usdx. I tried it today and ended up using the RBN to correct my reference frequency. I had forgot about it until my freq reports came back 800hz higher than it should have. After correcting the 27mhz to 27.001600 it was showing up correctly. (I figured the corrected adjustment would have been 1560hz). It’s a learning experience all around.

The USDX sounds good and also better on frequency. Thanks for posting this.

When I got my RS918, the hole in the stock microphone wasn't here. I actually ordered a different mic, and it improved my audio a lot.

You indeed have good luck with the Chinesium qSDX ;). I'm currently building the uSDX SOTA from scratch but unfortunately my LM4562 dual opamps IC seems to be of bad quality so I'm waiting for a new part. I only got reception below 500 KHz currently... The SI5351 synthesizer is working fine, also in the 14 MHz range where you should calibrate it and the 74CBT3253C seems to be within spec as well. My scope isn't that good but I seem to get some RF signal through it (on all 4 channels and on any frequency)... however, only in the first 500 KHz I get an amplified signal coming through the opamps (and I can hear something resembling noise through the speakers). At higher frequencies I only hear small pops when using the buttons and the scope signal is as flat as a pancake...

Tks buying the approved version of Guido's radio

Receive audio on the Bitx 40 is almost hi fi. Limited filtering and no AGC but they were $45 for the board.

Walt. Agree with your comments on the first two. Third was less smooth than the first two. I'd say the tru SDX would be the best of the lot with maybe a 50 Hz change in frequency. But I'm guessing that either an IC705 or FT818 (with a better microphone) would sound slightly better than all.

really good folks here also.!!

I have just ordered a QMX, to go with my QCX and TX-500 73

great video I also own the third radio you tested. I have had great results on cw guess I should try SSB here. and thanks for the link to Kevins group. 73 de Gary K8JCR

Good job Walt

To achieve a qso with about 5 Watts SSB is nice. You don't need a lot of money when you have the basics right to be on the air. I agree in the qrp world you need a perfect ssb signal and cw with no chirp or clicks to be competitive to other stations with higher power. I run all my transceivers from a rechargeable battery and I avoid power supplies.

Great video which you should follow up with a receiver spectral comparison , maybe using an sdr as pan-adapter at both ends

Good review! Giovanni I0KQB

I agree, the third transceiver had a more natural audio. I'd say it had more lows, a nice full midrange and not the harshness by emphasized highs that the other transceivers seemed to have. Why we might ask? Mucking around with guitar transducers and preamps tells me that it could be the microphone itself because not all electrets are equal and some are really fabulous or it could be the filtering aka equalization thats built into the audio chain. Hard to say, I doubt it has anything to do with compression because thats used to keep dynamic range or amplitudes within a set envelope and when applied compression should be frequency independent. Yea, I definitely liked it best and kind of doubt the others can do as well unless they have some really good tone adjustments available to the operator.

Thank you for the video. I’ve had my eye on the radios as I do only SSB. I know I can’t compare them to my 7300 or 705, but the ‘bug’is itching to purchase one. I’m still on the ‘fence’. Your video was helpful- W1FYG

Just found you channel - good topics on QRP.......I may ask: did you already find a better mike/compression solution for the RS-918? Kind regards from Germany, DF7RO

Hello Walt, I saw your piece on QRP rigs, very useful. In the back ground I saw a Hammarlund HQ 170, do you know of any sources or videos for operation of these radios.

Were you using the push-to-talk button on the true USDX and the usdx or an external microphone

Walt, another great video. Thanks. I wish my usdx worked as well as yours. I believe I got a lemon. I think I will pour sugar and water on it and have a tall glass of cold lemonade 🍋. Is that a halicrafters behind you. I have the s40 and getting ready to restore it. Keep up the great work. Have a safe trip to the other side of the pond. Keep safe, stay healthy. '73

Hey Walt ... great review ... what connectors are you using to go from the antenna connector on the (tr)uSDX to your attena?

Good Test. What was your antenna for this test and how was your SWR for the 3 radios? In IMHO I don't your audio was any better on the last radio. I believe your audio was best on the first radio. Thank you for sharing the test results.

Awesome video. I own all three and have never used them on ssb so I found your test informative. I like all 3 rigs but my 978 has the best receiver on cw. The peaking filter makes a huge difference. Of course the 978 is over twice the price. I am glad I found your Chanel. 73 WA6MOW

That last one was really impressive. Were you using the same mic for all of them?

That was really helpful. I just received a uSDX from China and took it out on a SOTA activation on Sunday. Got poor audio reports. So I'd be interested to see what you do to tweak the settings.

What about the "5W uSDX 8-Band HF QRP SDR SSB/CW Transceiver"? Is it the same as the one in your videos, it looks a little different.

More QSB than your change in power. Sounds like you like to tune for a slightly higher frequency voice frequency, this would result in your audio sounding a little low. Either RIT or XIT would fix that. Maybe you could show a video of what your reception sounded like so we can compare it with with your transmit audio.

what kind of red usdx mic did you use? and what kind of jack is that for the extra mic substitution? so i can buy it the better one. Thank you

Interesting comparison Walt. Thanks for the links to those FB groups. I have 2 low $$$ QRP rigs and I am 99% CW POTA op. For low $$$ CW, the Venus Tech SW-3B is the winner. What Guido has done with the (tr)uSDX SI5351 to produce SSB is a first ever. When I set up the (tr)uSDX for the first time, I said what the hell and tried SSB via the internal mic. I checked into the ECARS net on 7255, After I got a 57 with good audio from net control, I replied it was a kit radio. The whole net got their belly laugh of the day! It will be interesting to see what Manuel and Guido cook up going forward. As a side note I watched a video about a bench test of the 3rd radio you ran. Between non-compliant emissions all over the place and acting like a dummy load pocket warmer on the higher bands IMHO the radio is just more Chinese Junk! 72 de KE2YK @ ke2yk.com

My experience as yours. The (tr)uSDX sounds good with both internal and external mic but the "uSDX" (brick) radio also has pretty decent tx audio, internal mic and external. At least from my experience listening to various online SDRs. Out of those and the X5105 and the most recent IC705, I am not sure which I really, really like the best. The "uSDX" (brick) radio is almost as good as the X5105 -- especially since it doesn't have the birdies and squirrels that the '5105 has -- and even without an ATU I think it's the best of the uSDR radios I've played with. I'm still getting used to the '705 so I'm not gonna even go to comment on that. But the uSDRs are really quite inviting, if not just for the price. So yeah, they are surprising little radios. 73 de W8IJN

Great test for all three. Does the USDX still have 6 Meters as a band in It? Thanks for sharing.

Thanks for the comparison video!. I recently purchased a (tr)uSDX from one of the approved builders. Seems to work fine. I assume you were using the built-in mic on both the uSDX based radios. Have you tried an external mic? I spent a few minutes last weekend hacking up a cheap speaker/mic to use with my (tr)uSDX; have not tried it out yet.

What antenna were you using going into Iowa because it was great. I’ve never been able to get signal out that good.

Walt, My uSDX pocket 3 bander should be here tomorrow. At local PO today.

Nice review! What are the prices for those radios?

I will go for Usdx. I like the form factor in metal case. Bangood is the real Chinese clone. There are other clones of clones with quality control issues. Bad solider etc. This is based on reviews and the Bangood one seems to be the the most reliable

Great video Walt! Let me know if you'd like a QRP to QRP QSO when you cross the pond.

Walt, That was an awesome video. What antenna were you using? KO4HPC 73

On that trusdx, check the windings on the toroids(L2?) Also use a hand mic.

Walt, what do you recommend as a wire to purchase so it can be connected to an external battery for the red radio? I have one on the way, only seems to come with a wall wart. Thanks!

Well I went for the RS 918. I hope I guessed correct. I have several HF Signals rigs bit really eanted a waterfall thus my decision. How do you like yours now given it had been a year.

Can this Qrp radio get into 11 meters.

The 918 and the truSDX seemed to be off frequency or something. At least for the truSDX you can correct it. I think in menu 8. DL2MAN did also a video on how to tune the radio. I wonder if a external mic would improve the audio as well. I agree that last one gave better audio.

That is definitely a good way to know how your rigs are working/sounding! I wonder how much difference there will be from the QTH antenna vs the portable/field antenna you take. I'm sure there will be some purist/haters who won't like these little QRP rigs. 73

The person at receive end can do an RIT adjust. They all sound good but that QSDx did sound good, maybe just more centered on the channel....or you got a good one!

What antenna were you using for these tests? A thousand miles on a pocket rig is pretty inspiring, but if it's on a portable antenna it's even more so.

WHAT ANTENNA WERE YOU RUNNING ?? SOUNDS GOOD FOR SSB. ANY COMPRESSION ADJUSTMENTS ? MICROPHONE RESPONCES MAKE A DIFFERENCE. I LOVED CRYSTAL MICROPHONES FROM THE 50'S THE BEST, BUT THOSE ARE LONG GONE. THANKS VERY MUCH FOR THE VIDEO !

There seem to be many sellers of the uSDX unit. Where did you obtain your unit from? Do they all come from the same factory?

Nice comparison Walt! Out of the 3, which one had the best RX audio (sensitivity / readability)? tnx - 73 - KF6IF

Hi Walt. Thank you -- so much --for the comparison! I have the uSDX (same one as you). I have been trying for months, over various QSOs, and lots of tweaks, but have not been able to equal the audio quality you have been able to dial in. Could you relay us the menu settings that have worked so well with you? It would be greatly appreciated by everyone. THANK YOU! 73, Eric KB1EHE

A really long-winded comment, but it might be helpful to some.: Yes, you were slightly off frequency with the first 2 rigs. (I'm assuming the net control op went to the trouble to ensure he was dead-on frequency. Net control ops are usually careful about that.) I know that on the (tr)uSDX the frequency can be tweaked in software to get it right, and I'm guessing you or whoever built it hadn't done that since the rigs are pretty close to begin with, usually within a couple hundred Hz. But good SSB requires perfect frequency adjustment, down to just a few Hertz, not a few hundred. In the past we ALWAYS had to tune in each voice with our RIT, each and every SSB QSO, and retune a couple of times if there was any drift in either rig during the QSO. If we owned a cheap or old rig we would ride the RIT knob all the time. It wasn't just a matter of punching in a frequency and being precisely there, as is usually the case these days. But you will still have to tune in the contact if your rig is even slightly off frequency, or theirs is, and even modern rigs can still be off frequency. That's why rigs have RIT. I still tune it out of habit, never expecting perfection from my rig or from others. I'll even shift the RIT frequency a bit to adjust the pitch up or down so I can understand someone a bit better through the noise even though I know I am not setting their voice quite on frequency. But whatever works. This is ham radio. Having said all that, a net control station seldom tweaks their RIT frequency adjustment for each calling station because every rig communicating with them may be right on, or a little high or low, and it's a pain in the butt for a net control station to keep adjusting that, especially as they are usually taking notes at the time. So if they can understand the other station they just listen to them slightly off pitch, as this net control op did you. In a normal QSO, you just tweak in the other station with the RIT and forget about it. With the advent of software controlled gear the tiny, inexpensive QRP radios bury the RIT in software menus, making it less accessible and inconvenient to adjust. I would personally prefer to have an always available RIT knob on my tiny SDR's, but that's the way it goes. So it behooves hams with these little rigs to take the time to get their rig's frequency reference set dead on at the temperature they will usually be running it at, and to check it every few months. That's just good ham radio practice, and is very important in group QSO's, especially when running mobile HF, as more hams are starting to do. If all the hams ensure their rigs are precisely on frequency then RIT will seldom be necessary for SSB work. But everyone needs a very stable and adjustable frequency reference in order for that to happen, and not everyone has that sort of stability in their rigs. Then there are SOTA and other stations that could be operating out of a backpack at 10 degrees below zero, and they, and you get what you get as far as frequency accuracy and stability.

What Mics are you using with these?

I am looking for about your product place lace me a message. When I post this , I am looking for more information on this. How can I have fun being and how much did they run and what their prices are and what is the range on them can I hook them up to a portable antenna and wonder how far can they reach out

the second rig was running the best tx audio

Sigo buscando un equipo para hacer sota, todavía no me convence ninguno, gracias por el video 73.

Who did the build for the (tr)uSDX?

Odd question, I am just getting into HF, do you think QRP is a good place to begin in HF. My finances are limited.

Something wasn't mentioned but here we go : the rs918 is a clone of the mCHF from M0NKA .

Chinese copies are not 100% horrible. But it’s possible to use a few transistor options on the RS978. It’s a different story on the uSDX because class E amplifier are not super flexible when it comes about transistor options. Yes, you can unsolder the one from factory and slap an IRF510 and get 10w, but the LPF may not be designed specifically for that transistor, which results on a poor efficiency, overheating and a poor harmonic attenuation. My (tr)uSDX scores better than 78% efficiency on all bands, and harmonic attenuation better than 43dB below fundamental. On the other hand, my recently bought uSDX plus v2 is unusable on 60, 40, 30, 20, and 17 is passing the FCC standards by a hair…

Totally unrelated, but when I tuned in to this video and head your voice I got confused since you sound like I went into Steve's Small Engine Saloon but about radio.

I’m guessing its the operator in iowa. His radio is tuned. Slightly off 328

Friday Nite QRP Net. Where, when?

Did the HOA lady help you out LOL

Where are the links to purchase?

The RS918 is around $400+. Why would we expect any other radio to win? You crippled it by lowering the power, but it seems like the best. I just bought the uSDX, which should do fine for me.

Can 20W be considered QRP

The MCHF sounded better... less distorsion

How do we find an approved builder for the uSDX?

You were slightly off frequency on the first one.

Walt, here's the link to the DL2MAN bench test of that 3rd Chinese pocket warmer you demonstrated! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Q1bTomgTMhQ.html 72 de KE2YK

Sure sounds like the RIT was off.

My city at Bangladesh get flooded so I was looking for solution for relief operation in a cheaper way I lived in London. Our cell phone network not cover vast flooded areas. Our city will flooded each year because of climate change so we need prep . Because cobra radio is too expensive for us we cannot afford.