[Boatanchors] Microphone cables and shields

[Brian Clarke]

Hi George,
>From your description, it sounds like you have some professional microphone cable,
which always has a twisted pair inside the shield. If the PTT line has the slightest 
possibility of carrying noise from the PTT circuit, eg, from a 12 V car battery, don't 
pair it inside the shield with the mic signal wire that's carrying only mVs.
It's better to look a bit harder for the correct cable.
73 de Brian, VK2GCE.
  George asked:

  I want to replace a mic. cable for a high-z mic. The cable that is on the 
  mic. has a shielded audio mic lead and an un-shielded PTT control lead. The 
  audio and PTT share the shield as a common ground.
  I have a length of mic. cable that I wanted to use as the replacement but 
  its a different type cable.
  The audio and PTT control are both encased in a common shield. Is this type 
  of cable for low-z applications or something else? I had never seen a mic 
  cable that had both leads in a single shield.