[Elecraft] Using iMic with KX3 and mains freq interference

[Richardson Brian]

Reply to Julie KT4JR, 

I use iMic with KX3 and it appears as another audio source to the PC which you select in FlDigi or Mix-W or whatever you choose to use.  

I did however suffer from power line frequency bars on the trace due to ground loops via the PC power supply but they were eliminated by inserting a pair of miniature audio transformers into the I/Q lines from the KX3 (taking care to maintain the relative phase of these signals).

With the transformers in place everything worked perfectly.  I used transformers recovered from other equipment so ran a frequency response/impedance measurement to satisfy myself of their suitabiity and the ones I used had a frequency response from < 20
hz to > 150KHz and I tried 600:600 ohm and 150:150 ohm transformers and it did not seem to make a difference.  A friend offered some which when checked had a frequency response way outside the audio band as they came from digital modems and were unsuitable.  If you are not sure then purchase new ones.  

Regards,
Brian  VK3CCRRegards,
Brian



Regards, Brian - VK3CCR