PSK with no Interface

Perhaps you have heard about PSK31 and the many other digital modes available to today’s ham radio operators.

You have gone the next step and know you need to, somehow, connect your computer soundcard with your radio’s speaker and microphone.

Many devices exist to help you do just that including US Interface, BuxComm, SignaLink, etc. I have my eyes set on the US Interface Navigator product to be my sound interface plus mop up a WinKey CW Keyer and rig control (CAT) in one box entirely powered by the USB port. Nice.

However, I am enjoying the digital modes today with absolutely no interface. How?


I was given a small computer microphone. This one is the type that is meant to sit on the table and pick up conversations nearby. I have it sitting directly over the speaker hole of my Icom 746. I fire up my MixW and easily decode the PSK31 signals in the waterfall.

What about transmitting?

That’s a little less polished, but functional. All I did was take the voice microphone off its stand and lay it next to my laptop. The computer’s internal speakers provide more than enough sound to send a PSK31 signal literally over the air in the shack to the microphone and out the radio. In fact, I had to turn the audio gain of the transceiver down a bit to make sure I was not over-driving the modulation.

I use my foot-switch to put the rig into transmit and then tell the software to begin sending PSK31.

From Virginia I have made easy contacts with Mexico, Kansas and Indiana using PSK31 in just two nights.

So if you are saving your money for a built interface or collecting ideas for a home-brew approach, GREAT, but go ahead and get on the air now using your rig’s microphone (TX) and a cheap computer microphone (RX). Remember to keep the transmitted audio levels lower than you think are needed. If you don’t you will splatter your signal all over the PSK range.

I am quite surprised how sturdy PSK31 is to make a trip in the air of my shack, but it works remarkably well.

Coordinating the foot-switch with the computer program transmission is getting old quick, but for the low price it buys you time and gets you into digital modes today.

1 thought on “PSK with no Interface”

  1. Another Method Idea:

    If you have an Ext Speaker Output Jack, you can use a cable from the speaker/headphone/audio output on your transceiver directly into the LINE/MIC Input on your computer.

    This will allow a direct audio stream without any ambient background noise or annoying PSK and general radio "noise".

    You will need to adjust the audio level from the transceiver output way down to a much lower "line level" volume. (usually by turning down the speaker volume on the transceiver a considerable amount…) You can see how soft or loud you need to adjust it by looking at the waterfall display on the PC running the PSK software.

    If your transceiver has VOX (Voice Operated Transmit) you can place your desk mic (or hand mic) in close proximity to the PC speaker (or ext. speaker) and turn on the VOX function on your transceiver, carefully setting the threshold to automatically key the mic when the PC is sending PSK tones out of the speaker(s). You can also adjust the level of the PC speakers to your liking as to allow for normal talking without keying the mic.

    This will also allow for you to hear the actual PSK tones for the entire length of the transmission with monitoring so it doesn't "get stuck in transmit mode" and overheat your transceiver.

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