Steve,
In nearly every case I can remember, a buzz or hum in an audio circuit
could be traced to a ground loop. The predominance of unbalanced audio
cables used to connect the components means that some AC leakage currents
will flow over the shields and thereby become part of the audio signal.
The easiest way to correct a ground loop is to convert the audio source to
a balanced output with a high-quality transformer. Use shielded
twisted-pair cable to connect the audio source to the load, floating the
shield on the source end. Ideally, balancing transformers should be used
at both ends.
73, Eric Lemmon WB6FLY
knightdriver20042004 wrote:
> I seem to be having a problem involving a kenwood tm701 with a Doug
> Hall RBI-1 on the link port of my Mastr II VHF repeater. It seems to
> have a buzz in the audio, or the dtmf regenerate feature of the RC-210
> controller. It seems to be so bad, that the Echolink program will not
> decode the dtmf. There is no problem at all when going direct to the
> Echolink radio which is located remotely. Is there an audio filter
> that I might be able to use to put in line of the transmit audio or
> does anyone have any other suggestion.
>
> Thanks for the input
>
> Until Next Time
> Steve...
>
>
> Yahoo! Groups Links
>
>
>
>
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