[1000mp] Mark V Push to Talk RF Spike

[Tom McDermott]

Mike:

	You don't mention what kind of mic, or the circuit,
so I have to guess here, but it sounds like the PTT switch
is completing an audio circuit (in addition to grounding
the PTT line). If so, the PTT switch make cause a coupling
Capacitor in the microphone or mic input circuit to suddenly
become connected, and thus generate a huge spike while it
charges up.

	Using VOX, you might not close the PTT switch, so no
coupling transient in the audio input would take place.

	Don't know if this is right, but it would mimic your
symptoms exactly.

	-- Tom, N5EG




> Hello Yaesu Fans:
>
> I have found that when operating PTT, that my Mark V
> spikes RF each time I key the microphone.  It does this
> with each microphone I have tried.  It appears that
> the spike is caused by noise input to the microphone
> preamp as the microphone cartridge is always in the
> circuit, so as to be able to be used for VOX operation.
>  With the microphone gain turned full CCW, there is no
> spike during PTT.
>
> I normally use VOX, so this is not always an issue,
> but I would like to find a possible solution to the
> problem.  The spike is greatly amplified by my linear,
> and needs to be eliminated.
>
> Has anyone experienced this issue?
>
> Thanks for your input.
>
> 73 and Happy DXing,
>
> Mike Schatzberg
> WB2AJI