Best impedance for sound-card input (mic)??

[aesmith]

Hi,

I think my transmitter is over-driving the sound input. What sort of total impedance should I be looking for when I add some attenuation? I tried a 100R / 1K divider, but that didn't work at all. I assume the transmitter isn't happy outputting into a 1.1K load. (I was checking the signal with the brilliant "Sound Card Oscilloscope" which I assume will see the signal exactly the same as Smartpropoplus).

Does 1K / 10K sound reasonable.

Thanks, Tony S