Chinese uSDR/uSDX Clone

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1

There are many variants of transceivers labeled as or related to “uSDX”. These radios use different connections. For some of them there are store cables [1, 2], for others there are no pre-made cables available in store at this time.

The radios in the pictures below will need homebrew cables:

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uSDR Clone Manual.pdf (378.0 KB)

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uSDRplus_red_corners.pdf (223.6 KB)

According to the information in the manuals the pinout for the mic connector looks like this:

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Would love to hear the logic behind the decision to use ring 1 for ground connection. Anyway, based on this pinout the audio cable to Digirig will look like this:

3.5mm TRRS tip (MIC) → 3.5mm TRRS ring 1 (RIG_AFIN)
3.5mm TRRS ring 1 (GND) → 3.5mm TRRS sleeve (GND)
3.5mm TRRS ring 2 (PTT) → 3.5mm TRRS ring 2 (RIG_PTT)
3.5mm TRRS sleeve (SPK) → 3.5mm TRRS tip (RIG_AFOUT)

Please report your results if you end up building the cable.

2 Likes
2

I have the red corners, I will build the cable the next days. I have a standard digirig, it will work with the cable configuración?
73s from Costa Rica

3

Yes, the cable described here is for audio and PTT. It should work with Digirig revision 1.6 or later in with any configuration of the serial port.

4

This is an update, I follow your instructions and I was able to make the cable to work with the Digirig, Indeed, I was able to make 1 contact ( solar storms are affecting propagation) I’m attaching some pictures here as a proof that is working.

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Something that I have to informed is that you still need a cable to connecto SPK output of the USDR+ and I connect the other side to the SERIAL port

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This is the homemade cable with the MIC connection

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I added a ferrite to the homemade cable as I have read in FB groups that this radio could generate RFI in the lines.

This is the setting being in used in JTDX :

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Let me know if you need something else, I will glad to help you to test any other cable in the usdx+

73 de TI3GB

5

Additional info:
PSK reporter in 12m at this hour:

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Several stations worked in FT8:

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I hope the pictures helps, let me know if you need any other testing or help, I will glad to help Dennis!

PD: I have a video I recorded with the usdx+ in action txing, let me know how can I send you.

73 de TI3GB

1 Like
6

Congrats on the successful cable build!
In your WSJT-X settings you can change PTT method to RTS over Digirig’s COM port. It’s more reliable than VOX. I look forward to seeing your video.

7

Is there anywhere for someone to buy the set up needed to get the USDR+ working on FT8?

8

The homebrew build for this cable is trivial, but if you prefer not to solder you can use one of these connector breakouts:

(pick 4 pin option)

1 Like
9

I have one of this chinese uSDR/uSDX and use it for FT8.
With DIGIRIG Mobile I work without VOX.
Pinouts are different from documentations. So I made cable myself.
See the pictures below for model of radio and pinouts.

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And cable pinouts are like this

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Thank You K0TX for the great job! :grinning_face:
73 de LZ2VN

1 Like
10

Vesko,
Thank you for sharing the cable pinout!

1 Like
11

I can’t figure out which type is best for the Mike and which type for the Audio, and there’s no schematic between the old and new transceivers, with the connection to the PC with the two jacks.

12

Does anyone have the schematics for USDR USDX Cat cables that terminate in a trrs compatible with digirig? Specifically, how should I connect the TRRS that goes into digirig cat port if the trrs out of the radio is wired as rx,tx,nothing,gnd?

I have made my own cat cable using an ftdi board that runs trrs to usb c (see screenshot), but it would simplify things for my pi zero setup if I could use the digirig for both cat and audio so I only need one usb port on my computer.

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13

i have the rig in the picture above.
(mine was marketed as uSDX+ v2 with battery)

it is a ‘straight shot’ with the trrs to trrs radio to digirig mobile.
ring2 is not used nor connected at either end in my cable
:slight_smile:

good luck
kb0wlf

14

For interfacing SDX+, check out this discussion:
Cable for Chinese uSDX+ V2 - Digirig Forum

15

Thanks both! yeah, after I asked this I found that other post about how a regular TRRS to TRRS cable should work, so I have one ordered now.

1 Like
16

If I only have the audio jack to connect, and if I need to use the microphone with the two jacks, how can I use the audio jack and the data jack?

17

K0TX I have an ASUS PC, what connection should I have?

18

Ok tank you