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[W1VT]

A mic input signal is on the order of 10 mW, which should be detectable on a 200mW digital scale.  A scope can better identify the signal so that you aren't fooled by noise.

Zack W1VT

[K0UA]

I would prefer you attempted to listen for the very weak signal coming from the soundcard interface into the rig.  Set up your pc and soundcard to transmit, and listen for the signal on pin 11 (audio input) and ground pin 2. with your earbud.  You should be able to hear it I believe.  though it may be pretty weak.   Remember this is a very poor way of detecting the signal, but I realize you don't have much in the way of test equipment, and with just a voltmeter, while you may get a reading, there can be a question of what that reading is.  Is it the signal from the soundcard or just noise pickup.  At least if you hear the signal you will be able to identify it and know it is the signal.

[5A1AL]

Jim K0UA I just sent you an email with an attachment.
I found out that the ground is on pin 3 not pin 2 as you mentioned by the forum. I measured the voltage on pin 11 using my digital voltmeter by 200mV scale both AC and DC, AC voltage on pin 11 was 12mV and DC voltage was 2mv!
I will added a copy of this message by the online discussion.

[K0UA]

Jim K0UA I just sent you an email with an attachment.
I found out that the ground is on pin 3 not pin 2 as you mentioned by the forum. I measured the voltage on pin 11 using my digital voltmeter by 200mV scale both AC and DC, AC voltage on pin 11 was 12mV and DC voltage was 2mv!
I will added a copy of this message by the online discussion.

Well, everything I can find is that pin 2 is the ground and pin 11 is the audio in to the transmitter.  Pin 3 is the Push To Talk Line.  I may be grounded if the radio is placed into PTT by either CAT or other means.  But it will have a voltage standing on it when it is idle, and if you take that voltage to ground (Pin 2) it will key the radio.

Again I don't know for sure if audio is going into the transmitter or not.   Anyone else want to weigh in here?

[5A1AL]

When I measured the values where the tune function is on by the software WSJT-X. Or there is a nother way to measure the output audio signal which supposed to be sent from the interface into the radio?

[K0UA]

When I measured the values where the tune function is on by the software WSJT-X. Or there is a nother way to measure the output audio signal which supposed to be sent from the interface into the radio?

Either using the tune function of WSJT-x or just starting a cq sequence, either way should work.
The idea is to see if the audio is making it to the radio or not. Then you will know which way to continue troubleshooting, the radio or the interface.

[5A1AL]

Hello again
Now I am using Signalink USB modem and still have the same problem. I can hear the audio signal which leavs the modem via the MON plug.
This time I am trying the FT8 and again I can recieve and decode FT8 signals without any problem.
Any Idea please