| K6SDW |
Rating:  |
2023-12-04 | |
| Basic transceiver ok |
Time Owned: 3 to 6 months. |
As LnxAuthor just reviewed I'm in agreement with most of what he wrote....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
The uSDX is a good choice for occasional field use like SOTA/POTA.
GL/73 |
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| KB3NWU |
Rating: |
2023-02-22 | |
| Not bad at all for the $! |
Time Owned: 3 to 6 months. |
| Plain and simple - I like it. No, it will never be anyone's main radio and will not even replace my 817nd. But, it is a totally self-contained radio (internal speaker, mic, swr & rf meters, and battery that last a long time) that is small (brick sized) and puts out respectable power for such an inexpensive QRP rig. It really is amazing how well the CW decode works! It takes up so little space, I just take this and an EFHW whenever I go away even if I don't plan to do any radio - just in case. I don't even bring the external microphone as audio reports are "you sound fine" with the internal microphone. When I received it, it was only putting out ~1W as the PA Bias max was factory set to 128. Turning it up to 180 I now get anywhere from 9 to 1 W according to the band (higher bands like 10M drop power). Your radio may vary but I've noticed a few quirks in mine: 1. 160M does not receive. 2. 6M TX power is 0. Yes, I know the radio is made for 80-10M but 160 & 6 are options in my radio, at least. 3. Mode will stay on whatever you choose for every band (if you are on 80M LSB & switch to 20M the radio stays on LSB & you have to go into the menu to adjust - annoying). 4. Can't adjust Tuning Rate @ 10k w/out going into the menu (shortcut doesn't work for 10k). 5. SWR & TX PWR meters only work in CW mode. 6. Noise Reduction settings go back to 0 whenever turning off/on radio, & even when switching bands or modes within a band (that one is a pain). 7. Backlight OFF does not work (light stays on). 8. Both ATT's act like RF Gain, increasing S-meter readings. In spite of the quirks, I really like this little radio and can recommend it. Also, at the price, it won't break you heart if you loose it or break it on a camping trip. |
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| K3TS |
Rating: |
2023-01-08 | |
| Not ready for prime time, despite the low price. |
Time Owned: 0 to 3 months. |
My friend Bill, whose call sign shall remain concealed to protect him from further predation, parted with 165 of his hard earned dollars in order to acquire this fine piece of Chinese engineering, and then handed it over to me at a club meeting and said, "Here, try this out". So I get it home, and the first thing I see in the box is no instructions, and no power cord. The second thing I see is that it has a fully charged internal battery, so I figured I would give it a try, at least until it goes dead on me.
This tiny radio covers 8 HF bands, all modes, and has an amazing compliment of features, including an internal keyer, and a code reader that works better than the one in my TS-590sg. In fact, I could not find a readable CW signal that it could not decode, which is simply amazing. The built-in keyer supports Iambic A and B modes, but was oddly wired backwards, so I had to turn my paddle upside down in order to send code with it. Perhaps there is a way to reverse it. The other thing that was backwards was the tuning knob. Turning it clockwise tuned down the band instead of up. Very strange indeed.
With all the features that are built in to the radio, it is operated almost entirely by one knob and one button, which makes for some interesting ergonomics. While you might eventually get used to it, there will likely never come a time when operating it will become either easy or convenient. But neither will it be impossible. There are many different parameters which can be set, and the resulting performance is surprisingly good. There are some strange issues that may not be easy to overcome. A good example of this is steady series of clicks and pops as one tunes across the band. When using the tiny internal speaker, they are merely an annoyance, but plug in pair of headphones and it sounds like someone firing a pistol in the vicinity of your head. That is a problem.
On CW, I was able to see an indicated 8 or 9 watts on my MFJ-870 wattmeter, but on SSB, the meter barely deflected at all. Perhaps there is a mic gain setting that I missed. I admit I did not spend much time trying to get it to work on phone. The radio worked so well on CW that I decided to try it out on that mode and see if I could make a contact. I hooked the radio to my tri-bander, a Force 12 C19xr, and started tuning the 20m band. The strongest signal I heard was EA9ACE calling CQ, so I sent my call ONE TIME with my upside-down paddle, and BAM, he came right back to me! Well I'll be, this little piece of kit actually works! The variable bandwidth DSP filter is really quite good, and I found that set to 500 Hz it was actually pleasant to listen to.
While there is no denying that this thing can actually make contacts, I think that a certain amount of operator skill (and a good antenna) are needed to overcome the shortcomings of its design, or maybe more accurately, its execution. I would not suggest this radio for a beginner, as it is just too hard to use. I also cannot figure out what you might use it for. Maybe as a cheap backpacking rig that you could leave behind on some island to let future explorers know you were there, though they may laugh at you if they are hams!
My theory is that two Chinese twin brothers, one an engineering school dropout, and the other a business school dropout, designed and built it in their basement. The engineer was nowhere near finished with it when the business guy rushed it into production. It is an ages-old story in the technology world, no matter what continent it occurs on. The clicks and pops in the speaker were the next thing he was going to work on, right after he figured out how to make the dial work in the right direction. His brother just thought he was taking too long and acting like a typical engineer. No problem, they will fix it in a revision later. Product Marketing 101.
I finished up my evaluation of this fine little piece of junk before the battery went dead, but Bill did eventually come up with a power cord and charger that worked, sort of. Would I suggest that anyone actually spend their money to buy this for any legitimate purpose? Not on your life. Using it is just too difficult, despite the relatively low price. The performance was not bad, so maybe if they fix a few of the problems on the next revision it might be worth another look. But not right now.
de K3TS
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| W5GNB |
Rating:  |
2022-05-12 | |
| Keep Looking, THIS isn't what you want ~~ TRUST ME !! |
Time Owned: 6 to 12 months. |
| Junk ~~~ Mine found a permanent home in the TRASH CAN ~~~ LOL !! |
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| LNXAUTHOR |
Rating: |
2022-04-30 | |
| an exercise in the management of low expectations |
Time Owned: 0 to 3 months. |
this radio comes in various forms, but all are clones of a QCX design using code from PE1NNZ's uSDX transceiver project (found on github):
Here are some facts: the rigs are of good to poor quality; you must tailor your receive audio using various settings, but it will still only be fair (tip: use headphones, as the built-in speaker, which can work in a pinch, is not the best); there are key- and encoder clicks; transmit audio is not the best, but works if you alter the PA drive setting; documentation is best from Guido's github site; there is purported ts-480 CAT support, but most sellers are liars - CAT needs to be compiled in, and room is tight for the extra code; forget AM BCB, not gonna happen, but SWL reception is best using LSB; no charging indication or voltage indication on the rig's LCD
my rig had firmware is R1.02v, while the latest is R1.02w;
muffled but copyable audio
CW decoding works very well! there is a single CW message slot w/editing; the 'practice' mode is nice for training w/o transmit
using solid carrier (CW), i found the following power out
160 - 6W; 80 - 7W; 60 - 10W; 40 - 10W; 30 - 6W; 20 - 9W; 17 - 6W; 15 - 5W; 12 - 1.75W; 10 - 4W; you can dial down to QRPp milliwatt levels use PA transmit max Bias
practice freq entry, band changes, filtering and noise reduction, and volume manipulation
i set up FT8 for wsjtx using a $7 Sabrent usb audio dongle; a 3.5mm 3-pole stereo jump from the rig's SPK jack to the dongle mic input; then built a 4-pole to 3-pole cable for the dongle output - TIP of 4-pole to TIP & RING (tied together) of 3-pole, GND [PIN 2) of 4-pole to GND (SLEEVE) of 3-pole; i used a rig VOL of 8+, and a NOISE GATE of 50, with a 50% vol output from PC and 35% input for the incoming signals for wsjtx - your PC, sound card may be different... start with a NOISE GATE of 150, then work down until VOX triggers transmit...
caution: always transmit into a dummy load for testing and a 1:1 or 1:2 resonance or you will pop the finals... the rig does have a FWD/SWR readout - a nice feature... you must have the s-bar selected for the meter
if you are looking for a rig that you can use at home or in the field to make a lot of contacts, this rig is not for you: it is not a kx2, 817, 705, or tx-500; there are many other much better qrp transceivers on the market; but if you want a rig you can play with or experiment with using different antennas, you may find a bit of fun at this cost point; i slapped on a silicon bicycle seat post cover (25-30mm) on the vfo knob |
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| WA6MOW |
Rating: |
2022-02-14 | |
| For $150 with a built in battery its great! |
Time Owned: 0 to 3 months. |
| I have the newer version. Mine has the red protectors on the corner and ergonomically its not as good as the one pictured. They both use the same circuitry. There are no instructions and they have a lot of hidden features. The most important one I found was that if you push the tuning knob in it acts as a volume control. I only use mine on cw and I have worked the world with it. The internal battery holds a charge for a long time. It does a great job reading code Mine puts out about 7 or 8 watts. The dsp is useless but the receiver is usable without it. Keep in mind this is a $150 radio. Its not even close to my KX2 but it is still great fun. I leave it outside on my patio with a wire strung in a tree and I have made numerous contacts. Perfect radio for learning code without spending much money or trying QRP. For around $150 bucks I highly recommend it. |
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| WT2W |
Rating: |
2022-02-13 | |
| Good for the money |
Time Owned: 0 to 3 months. |
'Cheap fun' would be the two words I'd use. I know others that have another two words for this xcvr.
I have had this little rig on CW and on SSB and it's a lot of fun. The audio sucked, but I overcame that by plugging in a decent hand mic. The built-in mic is worthless.
I see anywhere from 3w to 5w output on the bands.
Hey, it's QRP. Just today I was on 15m SSB and had many fine reports, signal strength and audio.
It's not a KX2 but it's also not $2000 either.
My other rig is a KX-3. If this little Chinese radio quits, I'll toss it in the recycle bin. But for now...
No Regrets. Jim
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| W8IJN |
Rating: |
2022-01-27 | |
| Toy Radio: Needs Re-engineered |
Time Owned: 0 to 3 months. |
This is an addendum & rewrite/revision of my review of the Chinese "controls on top" uSDX transceiver of October 2021.
The first one, which was the subject of the first review, was pretty doggy. I have since gotten another of these beasts and have decided to modify my review. There appear to be two different versions of the same box floating around on eBay and Aliexpress. The quality of these radios -- and this applies to the other designs/builds that I've tried as well -- varies from unit to unit. Thus what can be said about the spectral purity of one unit can't be said about the next one out of whatever assembly camp these radios come.
One thing is certain: The "controls on top" with a battery but sans the red end bumpers is probably the best of any of them as a receiver and transmitter. That said, if you purchase one, you will find that a simple modification will improve the radio's audio/receive quality.
. . . What I did was remove a resistor at the input to the LM386 AF amp and replace it with an edge-mount 1k variable as a volume control. Wired this up in the standard configuration for an old-fashion volume control. That way you can run the internal AF gain at somewhere around 10, with the ATT2 set at 1 or 2 and control the AF output with the new volume control. This one simple change makes the radio a radio instead of a frustrating toy.
It's important to realize that (a) this is a fancy direct conversion receiver and (b) the original design and now presently available semi-kit is probably better than any of the so-called Chinese clones. The controls-on-top w/ battery version, for all its shortcomings, seems to be an easier radio to modify & use than the ones that have the colored toroids, even the one that has a built in battery.
At any rate, you end up taking your chances of getting a good one, no matter which of the various "clones" you try. At least the one presently under discussion seems -- in this instance with this particular unit -- be be a reasonable purchase. Thus the upgrade from two to three stars
----
I bought this little radio before DL2MAN posted a YouTube video comparing it to his "sandwich" uSDR transceiver. In that video Manuel ran the radio through various tests showing transmit efficiency and spectrum analyzer plots of the operation of the LPFs on various band. In some ways, after viewing those videos and reading online comments on the groups.io uCX list, I regretted my purchase. But the dang thing showed up on my porch anyway. So here are my views on it after a week some of use & fiddling.
The SSB transmit audio is horrible. In fact, I am barely able to call it SSB transmit. It sounds more like digitized FM or some such. And researching these Arduino micro radios, it should be obvious that SSB is a dreamland afterthought. Those who have such radios and are able to get real SSB out of 'em are lucky souls.
The receive audio at low volume levels is horrible. The AF output is digitally derived and then fed to a standard LM386 AF amp. The input to the AF amp is controlled in the processor and at low levels any signal just below audible is sent to the AF amp as hash, noise that is annoying as hell to anyone with tinnitus. Probably folks without that affliction as well.
. . . To fix this problem I run the digital AF gain full tilt after modifying the input network to the AF amp so that it does not overdrive the AF amp. After that, the sole control of AF levels is through a set of earbuds with an inline volume control.
. . . That said, the radio needs a real volume control. A knob and a potentiometer feeding in the input to the LM386 as any normal radio would.
. . . And the CW sidetone, well, you have to crank it up to full-tilt to get it to sound like 700 Hz. Any levels below that are digital buzzing that is not only annoying but way off frequency from the intended sidetone frequency.
Not having a spectrum analyzer as DL2MAN does, I am not able to comment seriously on the output cleanliness of the signals above 20m. (See link below)
. . . All in all, the rig appears to operate very strongly from 75m through 20m. Output power is in the order of 5 to 10W, depending on battery power versus 13.8VDC external supply. I've had a couple QSOs with this radio on 40m, 20m and 30m and have listened around on the higher frequency bands. Properly modified so the AF isn't scroungy, I can hear lots of signals on all the bands and have gotten decent reports on the bands I've tried using a 4BTV vertical antenna. Above 30m, however, power drops quickly to something less than 5W. Usually around 2W to 3W. DL2MAN blames this on the choice of output transistor (IRF510), which he says is too slow to be efficient above 20m. Between that and what may be bad design in the LPFs, I'd tend to believe Manuel is on the right track.
The radio's keyer seems to work very nicely. Speed adjustment is, of course, one of the buried menu items that prevent changing keyer speed on the fly. There appear to be some sort of message memories but I haven't taken the time to figure those out yet. If they work, cool, but I suspect the message memory operation is as klunky as that of the X5105 (which is a much better radio).
. . . The internal battery -- which I'm betting is about the same physical size as the one in the Xiegu X5105 -- seems to last pretty long, even with the display backlit. I've had the radio on for hours at a time and have pulled a few QSOs on the battery with no appreciable change in operation or output power. The radio comes with its own charger -- at least in the eBay version I ordered -- and with the Maoist sounding admonition that use of any other charger is forbidden. Forbidden. I guess if you use another charger the Organs will come to struggle you in some dark corner of the security apparatus.
The radio comes with no instruction manual or schematic. Various uSDR groups have scrounged up a couple versions of the manual and a board lay out with schemos. You're basically on your own with this one unless you have the digital resources and can find the source info online.
So would I spend this money again? Nope. There is another version of this same radio that comes without a battery, a different set of toroids in the LPFs and a different physical layout. That one and its recently introduced "with battery" clone might be interesting to investigate but after this experience, I'll stick with radios that seem to work better even if they do cost considerably more.
. . . This is basically a poor man's POTA/SOTA rig for those who want their ears blasted out and who enjoy trashy sounding receive audio plus dubious SSB transmit. It's a toy. A cheap toy that could do with serious rethinking and rehab. If you want to experiment with uSDR style, Arduino-based radios without going through the joy of building one yourself, maybe this is a good place start. But don't expect much. And yes, I'm being outrageously charitable giving it two stars. It transmits. It receives. It needs serious modification. And it ain't a SSB rig by any means. Two stars and my own less Maoist admonition to give it a pass.
Here's a link to Manuel's review: https://www.youtube.com/watch?v=Q1bTomgTMhQ&t=600s
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| WB0GAZ |
Rating: |
2021-10-22 | |
| Multiple manufacturing defects, no schematic - advise caution |
Time Owned: 0 to 3 months. |
Two updates 22 Oct 2021: (1) This unit was shipped Sept. 2021; other versions are appearing on china-based marketplaces since then. (2) An incomplete schematic/parts layout PDF was received from an ebay seller and has been archived at https://groups.io/g/ucx/files/usdx-controls-on-top-oct-19-2021. My review rating for this device is unchanged (=good and clever design, but terrible build quality.)
Before you buy one of these on ebay/aliexpress/etc., I recommend perusing the groups.io group below where the official (open source) project is discussed.
https://groups.io/g/ucx/topics
My unit - reviewed here - has internal battery, controls on top rather than on front, and is also based on (appropriated from?) the underlying open source project linked above. This unit arrived with a number (6 and counting, one appears to risk internal DC power bus electrical short circuit) of manufacturing defects I've documented in postings on the groups.io group above. Correcting these has been an effort as no schematic was forthcoming (EDIT - the schematic that is mentioned above is consistent with, but does not completely document, this version of the radio.)
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