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MH2 Modification


w0rw
 

This an old microphone but it was causing me issues.
The mic element was wired so that it was always connected.
That allowed shack noises to trip the Tx on in the VOX position.
i rewired the mic element (white wire) to connect to the unused NO PTT switch terminal.
Now it is wired like a Motorola Mic. The mic element is only connected
when the PTT switch is closed.
Paul    w0rw


Geert Jan de Groot
 

Sorry for being dense, but isn't the point of VOX that you doin't need to push the PTT, and if you don't want the VOX to trigger on shack noises, you switch off VOX and enable PTT operation instead?


David Ferrington, M0XDF
 

Or adjust the trigger point - my VOX only triggers when I speak.
73 de David, M0XDF (K3 #174, P3 #108)
-- 
The lame man who keeps the right road outstrips the runner who takes a wrong one. The more active and swift the latter is, the further he will go astray.
-Francis Bacon, essayist, philosopher, and statesman (1561-1626) 

On 25 Feb 2021, at 15:40, Geert Jan de Groot <pe1hzg@...> wrote:

Sorry for being dense, but isn't the point of VOX that you doin't need to push the PTT, and if you don't want the VOX to trigger on shack noises, you switch off VOX and enable PTT operation instead?


w0rw
 
Edited

When you operate QSK on CW the VOX must be on, K3s manual p.32.
That leaves an open mic.
Paul  w0rw
i have added details of the circumstances that produce this issue:
 i switch between CW QSK and USB frequently,
When i am in the USB mode and the CW VOX is On because i have not turned it off,
but it not being used. (i don't want to push 2 or 3 switches to turn the VOX off or change  Mic gain settings just to operate USB).
In this USB/VOX On condition the  mic trips the Rig to Tx when there are any loud noises around.
   i use the USB mode for FT8 so i am not handling the mic but any loud noise in the shack trips the VOX on. i did try to reduce the mic gain, That of course stops it. i tried setting the Anti-vox up higher but that only had limited effect for noises.
   i could just turn the VOX off when i am on USB,
i just thought there was no reason to leave the mic hot when there was an unused switch right there in the mic to switch it off.
i have not noticed any ill effects of having the mic line unterminated.
If i wanted to use a Studio VOX mic or a headset VOX mic i might
add in a foot switch.
The MH2 is just an old hand mic.
If you don't have this problem you won't want to make this modification.
Paul  w0rw


Bob McGraw - K4TAX
 

I don't find that to be correct.   No audio is available in CW mode.  VOX is the way the internal keyer handles the TX control.   Using a foot switch does the same thing. 

73

Bob, K4TAX

On 2/26/2021 8:35 AM, w0rw wrote:
When you operate QSK on CW the VOX must be on.
That leaves an open mic.
If you don't have this problem you won't want to make this modification.
Paul  w0rw

Virus-free. www.avg.com


Bob McGraw - K4TAX
 

Just to be sure, I fired up my K3S in CW mode.  The VOX automatically comes on in CW mode because that is the way I have it configured.  See page 59 in the manual and CW Weight in the CONFIG menu.    Clearly there is NO AUDIO from the open mike when in CW mode.   Likewise, when the VOX is off in CW mode and I use the foot switch for PTT, there is NO AUDIO from the mike.

Now switching to USB or LSB the VOX is automatically OFF.  Again see page 59 in the manual as reference above.

My mike is either a Shure SM-58 which has no ON/OFF switch or my Behringer XM8500, or my Tentec 709A which does have a PTT switch but the mike is "hot" all of the time. 

Configured correctly, it is no issue and does not require changing any VOX settings when switching from any mode to another mode, including CW.

73

Bob, K4TAX


On 2/27/2021 9:04 AM, Bob McGraw - K4TAX wrote:

I don't find that to be correct.   No audio is available in CW mode.  VOX is the way the internal keyer handles the TX control.   Using a foot switch does the same thing. 

73

Bob, K4TAX

On 2/26/2021 8:35 AM, w0rw wrote:
When you operate QSK on CW the VOX must be on.
That leaves an open mic.
If you don't have this problem you won't want to make this modification.
Paul  w0rw

Virus-free. www.avg.com