Re: Gordon Gibby Digital Interface

Gordon Gibby <ggibby@...>

Since you aren’t getting transmit power, I would change that 47K to 4.7 K. 

The other one I would leave alone. 

If the rig goes in the transmission, and the only thing you have to do is provide enough audio to get the output that you want.  BitX’s need a bit more audio, as does the line input of icoms.   It all depends on what the transceiver requires.  

If you still don’t have enough output, change the 4.7 K in the audio path to 1K!!!

On Oct 19, 2019, at 18:48, Sascha Bohnet | DL5SMB via Groups.Io <saschabohnet@...> wrote:

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Still fighting to get the interface working.

I did make direct solder connections to the usb sound card - but the problem was something else. I did not pick the hot end of the poti but the wiper. So the RX path is pobably okay now.
But if i try to go to TX mode, the radio switches to transmission (vox) but I do not get any output out.

Comparing Davids schematics with Gordons original circuit, I noticed a change of resistors, probably  a confusion:

R3 which connects the sound cards left left output channel to the 500 Ohm Poti before the tranformer is a 47k resistor in Davids kit,
in Gordons documentation this resistor is 4,7k oder 10k (depending on the signal level) and is referenced to as R12.

In the vox circuit of Gordons documention the signal of the right audio channel is led through a 47k resistor to the base of the transistor Q1 -
in Davis kit this is a 4,7k resistor.

I will check tomorrow if changing both resistors helps in my case. And then I will give some feedback to Rob about the C60 tapping :-)

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