The PSK31 saga continues

Tonight I made an interface between my PC and the FT757.

It consists of a potentiometer in the TX audio line between the line out on the sound card,  an opto-coupler to control the PTT via the RS232 port and a direct connection from the AF out port into the line in on the sound card.

With all this in place PSK31 should be a breeze.

I made a few CQ calls on 20m and tried answering a couple of calls but I had no success.

I am not sure if the FT757 has the TX and RX frequencies correctly aligned. I guess any misalignment between these would see me receiving at a different place to where I am transmitting. Given the very narrow bandwidth of PSK31 this may also be causing me a problem.

At least I have sorted out the audio levels, or so I thought. It turns out when I input audio through the PATCH connector it is paralleled with the microphone socket on front and, with the microphone connected to the FT-757 the transmit signal is less than with the microphone disconnected. The microphone is also ‘live’ when the rear panel PTT is closed.

I will try making some more contacts tomorrow night.


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