I've seen that issue with other radios, mostly while mobile if transmitting 
on high power with the engine off. It's a low voltage thing I'm guessing, in 
fact the mobile in our car now will do that. If I have the engine on, no 
problem, off it will do that and I've seen that from a lot of Kenwood 
mobiles. I'd check your power supply, power supply connections, clean 
contacts and what not, I'd bet the radio's not seeing the voltage it wants 
to. id' say amperage but I see mobiles do that all the time wired direct to 
the car battery which is full charged so it must be looking for that 13.8 or 
what ever volts and not the 12 you get with the engine off. I'd bet yours is 
not seeing the voltage it wants to.

-----Original Message----- 
From: Tom Behler
Sent: Sunday, November 01, 2015 6:17 PM
To: [log in to unmask]
Subject: Interesting TMV71A Issue

Hi, everyone.



Well, last night, I got rid of the gremlin that was causing issues with my
ability to play selected audio files using Winamp, but now, another gremlin
has appeared in my shack.



This time, I'm experiencing a very strange problem with my Kenwood TMV71A.



The problem occurs mainly when trying to transmit with high power on 440,
but it happens occasionally when trying to do so on 2 meters as well.
Basically, when I transmit with high power, especially on 440, the rig shuts
off for a split second, but then comes back on.  It's almost as if the rig
is not happy transmitting on high power for some reason, again, especially
on 440.



I discovered this issue late this afternoon, as I was doing my usual monthly
tests of equipment, antennas, etc., at least as best as I can from here in
the shack at the home QTH.



In trying to diagnose the problem, I have done the following things so far:



1.  My first thought was that something has gone wrong with my outdoor
Diamond X200 VHF/UHF antenna, which is fed with RG9913 coax and is on the
roof of my house at a height of approximately 35 feet.  I took SWR, as well
as forward and reflected power readings using my TW2.  Both on 2 meters and
440, adjusting the meter for each gand as I went.  my SWR's on each gand are
between 1.2 to 1 and 1.3 to 1.  On medium power, my forward power on each
band is between 9 and 10 watts, and my reflected power is either at 0 watts
on 2 meters, or point 2 watts on 440.



2.  I then tried switching jumpers between my TW2, and the Diamond X200
connection on my MFJ window feed through panel.  Again, no change.
Admittedly, I haven't swapped all jumpers out, but at least the initial
jumper swap didn't change the results.



3.  I then did a V F O re-set on the TMV71A, with again, no change in my
results.  I'm a bit reluctant to do the full re-set, but may do so as a last
resort, since I have the TMV71A programming cable, and also have all
memories and menu settings saved in a data file for the rig.



One other thing I might try is to see if this happens with the TMV71A that I
typically use when camping out at the RV.  It is here in my shack in a box
for the winter.



Before I go too crazy with all this, though, I'd like to know whether anyone
else has experienced this issue, and if there are other ideas out there that
I might want to try.



Thanks as always for the help.



Tom Behler: KB8TYJ