[Elecraft] RF in Microphone

[Jim Brown]

Hi Jim,

RF feedback is most often caused by improper termination of a cable 
shield. The only good termination of a cable shield is to the shielding 
enclosure (that is, the chassis). I know nothing about Heil mics, so 
can't offer advice about their adapter. I would take this issue up with 
Heil.

But don't assume that RF is the only possibility. The mic gain and/or 
the compression may be turned up too high, both of which can make you 
sound pretty awful. And the adapter may be mis-wired -- every brand of 
JA radios uses a different pin-out for their mic connectors. Elecraft 
uses a pinout that's close to one of them (or may be the same). So 
connector wired for one radio is usually not right for another. Some 
people complain about "different standards," but this is an example of 
there being NO standard, and each manufacturer throwing his own darts at 
the board.

If it is a wiring issue, all you need to fix your problem is a few hand 
tools and a soldering iron to open up the connectors and rewire them 
according to the manuals for the respective components (the mic and the 
radio).

The Yamaha CM500 is widely used by K3 owners. I've used one since a 
local ham introduced our contesting club to it seven or eight years ago. 
Both mic and headphones sound very good and it's quite comfortable. It 
plugs straight into the jacks on the rear panel. It's an electret, so 
you'll need to turn on  bias.

73, Jim K9YC

73, Jim K9YC

On Sun,3/26/2017 9:31 AM, Jim Kutsch wrote:
> I am a new K3S owner and very pleased. However, on SSB, I am getting reports
> that my audio is distorted sounding like RF is getting into the microphone.
> I'm using a Heil PR-781 with the XLR3 to 8-pin microphone adapter cable. I
> had some RF microphone issues earlier using the PR-781 with a KX3 but a
> better shielded mic cable and a common mode choke resolved it. Any
> suggestions before I go in search of a different mic? Also, any
> recommendations for a boom mount microphone that would be a better choice
> for the K3S than this PR-781?
>
>   
>
> Thanks and 73, Jim, KY2D
>
>   
>
>   
>
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