[Boatanchors] DX40 Mic input

[Walt Cates]

Dave,

Question #1)  I am replacing the rear mic connector with a two circuit 1/4
inch audio jack so I can add PTT.  I decided to replace the old coax with
new, probably RG174 (or is it 175?).  May I ground both ends of that coax
shield?

Question #2.  The reason I want to ground both ends is that I am adding a
shunt potentiometer from mic to ground at the rear connector to control the
mic "gain".  Actually it will be a mic attenuation.

I am not really familiar with the DX-40. However, that is most likely not coax but shielded microphone wire.

It is not grounded at both ends to prevent surrounding voltages from inducing currents in the shield. Leaving one end of the shield open has a definite design function. You do not want current flow in the shield.

 Walt Cates, WD0GOF
https://wd0gof.com/Hallicrafters

A majority of acceptance is not proof of correctness.
https://wd0gof.com/bible-study/commentaries/


________________________________

wa at msn.com