(tr) uSDX 5 BAND HF TRANSCEIVER - THIS IS NOT A CLONE!

The (tr) uSDX 5 Band QRP Transceiver is product designed and developed by DL2MAN and PE1NNZ. This is an original design and is actively being used worldwide. What do you think?

 

I've had one for a couple months now. It's an intriguing design and does a lot for the size and price. It has some warts though.

Negatives:
The base noise floor is bad. With no antenna connected it shows S3+ noise.
The RX audio is poor as well. Even with headphones you can't turn it up much before it begins to distort.
Also, my copy as well as others' have some sort of AC-60hz-like "hum" on one or more bands. Mine is worst on 20m but still evident on other bands.
Input via the buttons and dial can be flakey at times.

On the positive side:
The size.
The price.
Internal Mic (if you're into SSB). I strictly use the internal mic and it works well.
Modding capability. You can change the supported bands.
Community Support.

I wouldn't suggest this as a first QRP or Portable rig, but I view it as a platform for experimenters or those who want the lightest possible station. Even with the warts, it does work and I've used mine for POTA chasing and a SOTA activation (even making a DX contact). My next "experiment" will be to set up a lightweight FT8 station using this radio and my mobile phone. I'm normally not interested in FT8, but if I can do it with this radio and my phone, it could be a fun and interesting experiment.

Chris

 

I bought it 3 months ago. I agree on the negatives that you have exposed, but keep in mind that it is an open project and that with the next firmware it will be improved. As for the audio it is advisable to keep the output volume below level 8 and connect an amplified speaker, I use a JBL GO1 it is wonderful, as headphones I have a lightweight 32 ohm Sennheiser, it is fantastic. With a 9m ground mounted antenna and automatic tuner at the base, from Sardinia I connected NJ4P from Tennessee and PV2K from Brazil both confirmed on LoTW. Asia and Africa also confirmed, always with ratios never lower than 5/5. I miss Oceania, I don't stop!

 

Yup, it being a semi-open-source project means bugs will get fixed (within the limitations of the hardware), but it's an issue people need to be aware of. It's not a polished product. That's fine as long as you know this going in.

Yup. But...if I have to start adding amplified speakers and such, I might as well carry a larger radio. My goal with this one is to be as small and light as possible. Each additional piece of kit I need to offset shortcomings is another step back to a kit the size/weight of my KX2.

I use a homebrewed micro 40/20/10 EFHW with inductance coil. I was able to make contacts into France and California from Virginia (east coast of US). The little radio works, it's just a bit rough around the edges.

Chris

 

In fact, to make SOTA or portable I carry the micro-headphones, 2 battery packs of 3 x 3000 mAH and a very light EFHW 40 - 10, nothing else, it all fits in a small military olive drab bag

 

If you have not already done so you can subscribe to the Facebook group (tr) uSDX, there you will find many tips and experiences

 

I have a (tr)uSDX) on order. With luck I'll see it before EOM.

I also own an ALX-SSB radio (20M/40M - ~10 Watts). This is a hack of the KN-Q7A, itself another hack of an earlier rig. These are SSB only rigs. The digital VFO runs on an Arduino base. It also has a noticeable background hum on both TX/RX. I have decided this is owing to the OLED display. (multiplexing hash)

With an Arduino based VFO, I'm free the change bands, VFO range, etc using the free programming environment for the system.

The (tr)uSDX has the same vibe and language AND offers both SSB and CW!. It is also much smaller than the ALX-SSB.

It is no KX2 (or even a SW3B) but the (tr)uSDX radio offers a wide range of possibilities as the software is both open source and freely available. Happily, the full schematic, technical data etc is easily had for those who wish to chase after that part of the hobby...

My thanks to DL2MAN/PE1NNZ - this is such a wonderful time to be a ham radio hobbyist.

 

I fully agree with your thinking, and we take into account that solar cycle 25 is in its infancy, and it will give us many good times for QRP DX

 

Nice review....unfortunately I bought a Chinese knockoff and while the rig does work, the menu/rotary encoder on mine is a disaster and sometimes unreliable. I found a pushbutton hand mic kit for $15 sold by Pacific Antennas and with that mic the SSB audio sounds decent. However, I prefer CW

73

 

Great little radio. I just finished activating POTA 15 contacts within an hour.

 

It's a fantastic radio -- with patience and a good antenna, it'll reach anywhere you want on FT8.

I should note that the hardware is open design, but not the software, which comes exclusively as precompiled binaries. Even the hardware is licensed under a no-derivatives license, so if you are expecting to buy an open source radio to fiddle with, this might not be it. I bought mine because I wanted a platform to fiddle with the firmware, and I'm disappointed that I cannot. That's on me though: I didn't read enough about it.

Still having a ton of fun with it, though. It's my first radio, and it's nice to be able to dip my toes in HF for $100 before deciding how deep to dive.

 

K6SDW, you are one of the lucky ones. From seeing the reviews on the Chinese knock-offs, most are not. I bought a Chinese knock-off uSDX from Banggood. As a receiver, it worked ok for a while. As an SSB transmitter, it never worked. After several tests with a nearby ham, we found that the transmitted audio was extremely distorted and unintelligible using the internal or external microphone. Banggood sent it with an EU 220 volt charger, not the US 110 volt version. The PTT button was too big for the hole in the side of the case and stuck in the transmit position. Opening it up, one connection on the PCB wasn't soldered and the connections to the power amp were poor. It's a $165 brick, $185 with shipping. I asked for a refund from Banggood and they want me to send it back, $72 through USPS. DON'T buy this brick from Banggood. Consider getting the (tr)USDX, not a more expensive, poorly manufactured clone. 73, KC3MVS,

 

That's an easy problem to avoid, you buy it from the vendors approved and vetted by DL2MAN and PE1NNZ. Sunny from Aliexpress is safe AND she's active on the FB group if you happen to have issues.

Chris

 

When I was out last night doing a POTA activation I worked someone from the US who was using one of these on SSB at their home. He sounded as good as anyone else I put in the log.

 

Walt, K4OGO made this video with on-the-air recording at the distant station of the (tr)uSDX, uDDX and the RS-918.
Comparing QRP Transceivers On-Air - YouTube

Very well done and was the thing that caused me to drop a dime on getting a (tr)uSDX for my station.