[Elecraft] [K2] Transmit Audio Problems

[Jim Brown]

On 6/3/2014 4:54 PM, Michael Eberle wrote:
> It is adjusted as low as it will go with the carrier balance pot on 
> the SSB board.

I suspect a simple problem with the audio interface. Study my tutorial 
on this.

http://audiosystemsgroup.com/HamInterfacing.pdf

What sounds like inadequate carrier suppression could be AC hum/buzz due 
to failure to bond the chassis of the computer to the chassis of the 
radio. You also need a "pad" between the computer and the mic input.

A "pad" is another name for a simple voltage divider. It takes a series 
resistor plus a parallel resistor across the input of the mic. Values 
are not critical, but I would start with a 10:1 ratio, with the series 
resistor being the larger value. 1K ohms series and 100 ohms parallel 
would work fine. So would 470 and 47. There's no power being dissipated, 
so small wattage resistors work fine. Exact values are not critical, so 
you can use 20%, 10% or 5%, whatever you have.

Setting levels both at the computer and at the radio are critical. Study 
the tutorial for more detailed advice.

73, Jim K9YC