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Highland Ham · June 20th 08, 05:28 AM posted to rec.radio.amateur.homebrew

wrote:
I am currently building a radio - sound card interface for my IC-730
so i can use PSK31. AIUI, the mic that came with the rig contains a
preamp, so presumably the radio is expecting an audio level above a
usual mic. Does this mean I can simply use the audio level from the
sound card straight into the Mic input on the radio via a 1:1
transformer for isolation, with no need for a voltage divider to bring
the level down?

Thanks.
====================================
Transformer does not need to be 1:1 exactly
Suggest you include an approx 1000 Ohms trimpot to fine adjust the mic
port input from the transformer. Assuming the radio audio input
impedance is in the order of 500 Ohms.

Frank GM0CSZ / KN6WH