[Elecraft] K3 hand mic

[Don Wilhelm]

Bill and all,

One reason for "noisy PTT switches" is that the microphone is wired for 
VOX operation - which means that the mic element is always 'live'.  If 
the PTT switch closes before the PTT button travel is complete, you will 
hear a 'pop' as the PTT button contacts the microphone case.  In other 
words, I do not think the switch itself is the problem.

If you examine the Shure PA mic specs that was mentioned, you will find 
that the microphone element is normally open - in other words, you have 
to depress the PTT button to activate the microphone element.  Depending 
on the relative contact times of the PTT switch and the mic circuit 
(both on the same switch), if the mic element switch is activated after 
the PTT is closed, no 'PTT noise' will be present.

Many ham mics are wired so the mic element is always 'closed' which 
allows the microphone to be used for VOX without pressing the PTT 
switch.  That arrangement can cause noise as the PTT switch is depressed 
since the PTT button parts are still rubbing on the mic housing after 
the PTT switch has closed.

73,
Don W3FPR

On 4/9/2015 10:39 AM, bill wrote:
> SHURE 514B
>
> http://cdn.shure.com/user_guide/upload/423/us_pro_514b_ug.pdf0.pdf
>
> the switch will outlast anyone .... human or otherwise,
>
> the ptt assembly is not noisy ..
> my kewood mobile hand mic  squeaks as the button is pressed,$@!%$^*
>