[Elecraft] RFI in audio chain

[Jan Ditzian]

I have followed Joe's directions: I found a two-conductor-plus-shield 
cable in the junk box (aka hamshack) and wired it as he instructed.  It 
works properly as a microphone, but still has extreme RFI on 75 phone.  
I rechecked my other microphone, a Ten Tec Model 705 with a home made 
adapter from 4 to 8 pins.  That microphone shows the same RFI.  I know 
that my IC-730, tested last week, did not have any RFI on 75 meters, so 
I am still stuck as to why this is happening.

Both the "ugly" baluns (coiled hardline chokes) in this feedline are 
about 50 feet in length, and both are spiral-wound, not scramble-wound.  
I will try to do a radial survey on Sunday.  I believe that I already 
tried removing all other feedlines from the antenna tuner, but I will 
assess that again on Sunday.

A field-strength meter in my shack shows RF on 80 when I transmit, but 
there is some RF on 20 meters as well; there is less RF on 20, but there 
is absolutely no sign of audio problems.

73,

Jan, KX2A