| K6SDW |
Rating:    |
2023-02-23 | |
| Basic transceiver best for CW, so so for SSB |
Time Owned: more than 12 months. |
Update: If you operate mostly SSB I would not recommend this rig, TX audio is not good. However, CW is ok. Also, I would recommend the DL2MAN version instead of this Chinese knockoff ... he's the creator of the uSDX.
I operate mostly CW so IMO the uSDX radio on transmit/receive is surprisingly good, not great compared to my KX3, but for around $150 I'll keep it for field use.
SSB I found a mic kit for $15 from Pacific Antenna that really improved the transmit audio. I've reviewed the mic elsewhere
This radio is a work in progress....probably always will be.
My huge complaint, the menu system is POS, a disaster IMO. Typical multi-button pushes, sometimes it works as documented, sometimes the radio just sits there defying me. I find I have to turn off and on the power for it to respond again. In another review someone wrote the maker used a really slow Arduino CPU which may be why the rig misses so many button entries.
The uSDX is a good choice for occasional field use where, if an angry bear starts chasing you, throw the rig at his head and then run like hell....you'll be out a few bucks but live to tell about it...HI HI
GL/73 |
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| PA4VA |
Rating:   |
2023-02-23 | |
| Same issues as NB4M |
Time Owned: 0 to 3 months. |
I had the same issues as NB4M: after a few days the power output was gone. I had this with 2 different radios based on the same schematic.
I hope the problem can be found in the 3 BS170 PA fets.
Otherwise it became a receiver indeed. |
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| KB3TVR |
Rating:      |
2022-11-24 | |
| Atfer 50 QSOs, I think this is a keeper |
Time Owned: 0 to 3 months. |
I've had this little uSDR/uSDX radio from China for about a month now and I've had great success with it right out of the box (the version I have has the display on top, not on the end). I paid about $140 for it and thought it might be worth the gamble, and I'm satisfied. I'm running it through a G5RV jr. antenna in my attic and have been having no problems being heard. Of the 50+ QSOs to date, almost all are within a 1,000 mile radius (and the majority are 500 miles or less) though I did have a nice DX with an op in Cuba this week. Almost all have been CW. My typical signal report has been 559 or 569. Though it has a built-in lithium battery, I've been using an external power supply which gives the transmitter more oomph.
The down side: the user interface is clumsy and inelegant. The power goes way down on 15 and 10 meters, but that might be a factor of the attic antenna I have. Almost all the QSOs I have had have been on 20 and 40 meters.
Last remarks: I finally tested the SSB this week using the internal mic that is built in. I was heard in central Texas from my QTH near Baltimore with a report of 59 (which was probably generous on their part). Bottom line: I think this is a great little radio that is inexpensive and makes good use of the open-source software for SDRs.
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| NB4M |
Rating:   |
2022-09-12 | |
| QRP Bargin |
Time Owned: 0 to 3 months. |
Update: It quit after a few days. Had it stored in the box and upon the third use, no TX. Tried the reset with no success. Now I have a SDR receiver that's pretty poor in quality.
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Recommended and would buy again.
For the price you won't find a better deal on an eight band all mode QRP rig. I can only speak for CW mode, but so far it's getting the job done. Loaded with simple menu features and a consistent 4-5 watts output. Good buy for anyone wanting to try QRP or the seasoned operator. |
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| AA4WA |
Rating:    |
2022-08-31 | |
| Red Corner version - Ok for portable CW use |
Time Owned: 0 to 3 months. |
I bought this inexpensive portable (Red Corner uSDX uSDR+) HF transceiver to replace my CW only MFJ-9200 QRP rig and I am quite satisfied with it. It has an internal battery pack that seems to last long enough to make plenty of contacts and I also use it's external power input with my 10 AA rechargeable battery pack. My primary reason for getting the uSDX unit was it's coverage from 80 to 10. The MFJ-9200 did not have 12 or 10 meter modules as an option and 10 meters is important to me. Although results may vary between the many different versions of the Chinese uSDX, my unit has a nice 4 watts CW output on 10 meters and up to 7 or 8 watts on some of the lower bands.
Reception isn't bad, once you get the hang of using the various ATT settings. You really need to add db ATT on the lower bands, even up to 20 and 17 meters sometimes. There are different AGC settings, but I just keep mine on FAST. There is an AGC behaviour just by the fact that this is an inexpensive SDR type of radio. When you make a change or move to another band, be patient and allow the internal processing to catch up. You also need to utilize the Volume control (shortcut is to press the tuning knob and turn) and adjust it high enough to be able to receive signals, but not too high or it can squeal and make more noise than necessary. For my CW operation I always use earphones. It's also good to have some sort of external volume control on the earphones to allow the radio's volume to be up enough to work properly, but still not blast your ears out. With practice you can find a good setting to get the radio to receive quite well. The problem I had with the MFJ-9200, was that it only had one ATT position if you needed to reduce too much input signal. The uSDR has 2 ATT options. The ATT 1 seems to be the standard input attenuation and the ATT 2 seems to be sort of an I/F attenuation. I mostly use the various ATT 1 settings, but sometimes if I need to knock the gain down just a little bit more, I will move the ATT 2 up to the 1 or 2 position.
I also like that you can change the CW band filter to several different settings and since I tend to operate on less occupied bands, I like to leave it on the 1800 hz position. I'll move it to 500 hz, if things get crowded.
I have been very pleased with using this radio for CW portable. Power draw, even with 5 - 7 watts out is mindblowingly small, less than 2 amps on transmit and receive doesn't even move the needle on my power supply amp meter, although they say its 70 ma. The MFJ-9200 was 40ma on receive, so that's the only area where it beats the uSDX radio, but both are pretty insignificant for my use.
Using it for SSB TX? Here's my comment: It works. Barely.... Enough said. Although, SSB reception really isn't bad. Since it is a general coverage receiver, I listen to many different stations and shortwave broadcasts. I don't bother using AM for SWL'ing, just keep it on USB and zero beat. AGAIN, use the ATT settings judiciously!
This radio is an experimential design type of radio and if you are into programing, there are facebook sites where you can find out how to update the firmware. I'm not into that and just live with what I have. I also do not recommend this for new ham operators or anyone that doesn't have experience operating QRP. It does take patience and a special touch, but it's very much worthwhile with this radio.
I will update as I gain more experience with the unit, but for now I really like using it for my picnic table portable CW adventures.
Operational shortcuts and info:
1. Press, hold and turn the tuning knob for Volume adjustment.
2. Double click the tuning knob to change bands.
3. Double click the Mode button to change bandwidth. |
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| LNXAUTHOR |
Rating:     |
2022-05-04 | |
| fun rig |
Time Owned: 0 to 3 months. |
there are a number of variants, and a 'newer' version of this single-board qrp rig... mine came with firmware R1.02w, says 'uSDR+' on the front, and puts out ~5W... sellers are mostly liars and cheats, and mine was no different, as the rig should have come with an internal battery (there is a charging port and circuit), but didn't, there was no documentation, no clue about pinouts of jacks, etc. a tiny Kenwood-style mic was included...
features of these rigs can vary: for example, the buttons-on-top versions usually have SWR/FWD/REF readout available via a menu item; some may have a voltage readout; and some sport a UART-labeled port that more often than not is non-functional...
digital modes should work on all variants using VOX, which can be adjusted via a threshold menu setting...
a PC CW keyer, using a 2N2222 circuit will work well with all variants using various logging programs or flrig's keyer dialog
fortunately, my uSDR+, which sports a CAT port, accepts a 'normal' TX/Tip FTDI USB cable for PTT digital operations... my first problem was that while wsjtx worked well for ptt using the radio designation 'TS480,' this did not work for flrig!
the solution: in flrig, select the radio designation 'TX-500,' which supports a subset of the 480's CAT commands, then use 38400, 8N1... voila! flrig works for various functions... you then can run fldigi and choose flrig as the controller... fldigi can then change mode, freqs, etc.
i won't get into the SSB functions of these rigs, which was always meant to be an experimental feature - voice transmissions can be adjusted using TX Drive audio gain, adjustable from 0-8... most rigs come with a default of 4, but perhaps dropping that to 3 or 2 may help with any distortion or muffling - you will have to test your rig to find out... the buttons-on-top model worked best for me using the built-in mic element about 5 inches away - these 'thin' variants do not have a built-in mic, so you are at the mercy of the included mic... one fellow remove the LED resistor in the tiny mic to help with more voltage to the element after replacing a specific board SMD resistor with half-value in an effort to improve audio - but test your rig, mic and menu settings first
these rigs are cheap, and you won't cry if you drop one over the side while kayaking, or off the tailgate of the truck onto concrete... if you pop the finals by transmitting too long into a bad match, the requisite trio of BS170 TO-92 replacements will cost you less than a small cup of burnt java from that evil coffee-shop chain
all in all, this is a fun little rig, but as mentioned on my other review of the buttons-on-top, using one is an exercise in the managment of low expectations - you may be surprised! |
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| WA6MOW |
Rating:      |
2022-01-26 | |
| Works great on cw for $120 bucks!!! |
Time Owned: 3 to 6 months. |
| I own a couple of versions of this design and I have worked DX all over the world with a doublet. It is not a KX2 killer. I only use mine on cw. If you buy one, go to Big Lots and and pick up one of their $6 headsets with a volume control. Without a headset volume control you will not be happy. This rig reads cw as good as my KX2, maybe even better. I paid $120 for mine from an ebay seller in China.. The damn thing works. It has a nice internal keyer, sucks hardly any current, puts out about 3 to 5 watts. I compared the frequency readout to my Ftdx10 and it was right on. The dsp doesn't work but neither does it work on my FT817 lol. This is a $120 screw around radio which is perfect for learning code or getting your feet wet with QRP. Best $120 bucks that I have ever spent. |
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| VE3SIF |
Rating:  |
2021-11-08 | |
| Returned it |
Time Owned: 0 to 3 months. |
I had this radio for three weeks and had a lot of fun with it! It had issues, make no mistake. But I really liked it anyway and had some good success with it.
After three weeks, the receive function went south and in the end I've returned it for a refund.
I don't think its ready.
This video provides an overview of my time with it: https://www.youtube.com/watch?v=o4i7JWiVibw&t=7s
Before considering one of these radios, I hope you will check out https://dl2man.de/
You might also want to look at Hans' site at QRP Labs https://www.qrp-labs.com/qcx.html
Hope this helps someone. 73 |
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| W9WCR |
Rating:      |
2021-11-04 | |
| Wonderful fun radio and at a bargain price |
Time Owned: 0 to 3 months. |
GREAT little radio! 4 watts out on all bands and fits in your shirt pocket.
Amazing value for the $110.00. Worked as far as the Czech Republic from Chicago on 15 meter SSB.
It has a CW decoder which works great and I have been getting very good audio reports on air. Plenty loud for me.
Users have complained of squeals from the audio but this is like a direct conversion RX where the audio amp does the heavy lifting. Online instructions tell you to limit the volume to under 11. If you need it higher use an external speaker.
Like all QRP rigs this is not a beginners radio. QRP is a challenge, and that makes it FUN. Wonderful fun radio and at a bargain price !
Update: There is a VERY easy mod from the manufacture to prevent damage to the RX mixing IC when receiving very strong signals. It can be found here:
usdx-users@groups.io
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| N1IG |
Rating:  |
2021-10-30 | |
| Not ready for prime time |
Time Owned: 0 to 3 months. |
I bought one of the radios pictured above, from one of the many sellers. I was so disappointed that I sent it back after only 8 days.
The radio squealed if I turned the volume above 12. The mic connector was so close to the power connector, that they pushed against each other. When connected to a properly tuned and oriented mag loop, received signals were weaker than those received by a D74 using the internal bar antenna. The emissions coming out on the RX frequency were high enough that they could be easily picked up by other radios in my shack.
This is a knock-off of a design by DL2MAN, (see: https://dl2man.de and https://groups.io/g/ucx), and there have been many mixed reviews on the build quality of the knock-off radios. Some people have had good experiences, but many have not. You should read them before making a decision to buy one.
One thread in particular you should read is:
https://groups.io/g/ucx/topic/84769899#9152
if you have to pretend to be someone from another country to try and promote sales, then you probably already know what you are doing isn't proper.
And here is a YT video from the original designer, DL2MAN that you should also watch before buying anything:
https://youtu.be/LMm5GJhB5Gg
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