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Topband: Fix for ALC induced Key Clicks in FT1000MP MK V

To: <topband@contesting.com>
Subject: Topband: Fix for ALC induced Key Clicks in FT1000MP MK V
From: "Michael Tope" <W4EF@dellroy.com>
Date: Wed, 4 Jan 2006 22:57:11 -0800
List-post: <mailto:topband@contesting.com>
Hi All,

I had reported previously that my despite adding the W8JI
key-click modification to my FT1000MP MK V it was still
clicking on the leading edge character and also on intra-
word leading character (e.g. first character after a word 
space). W8JI suggested this was caused by ALC action
and that it might be mitigated by pre-biasing the external
ALC input with a DC power supply and indeed this turned
out to be the case (~ -3.5V on 160 meters). The external 
supply was not a good solution, however, as the 
adjustment was way too touchy to be useful in practice 
and the optimum setpoint drifted as the rig warmed up
during long transmit intervals.
 
Tonight I decided to get more familar with rigs ALC circuit
in hopes that I might be able to figure out a better fix. In 
doing so, the first thing I stumbled on to is the Mark V's 
TX IF gain hidden menu ("9-2").  This is a scrolling menu
that provides a drive level preset for each amateur band 
(-018 for 160, -035 for 80, -070 for 40, etc). The preset
ranges from "0" to "15" with "0" being minimum TX IF gain 
and "15" being maximum TX IF gain. My rig (as received 
from the previous owner) was set to between "6" and "7" 
for each of the 10 bands segments except for "-290" (the 
29.0 MHz segment of 10 meters) which was set to "8".  
Dropping this setting from "7" to "2"  for the 160 meter 
segment (e.g. "-018" segment) completely eliminates the 
leading edge clicks even when using VOX for the initial RX 
to TX changeover yet still provides enough excess TX IF 
gain to sustain some ALC action (about 1/3 scale) at 200 
watts output. I haven't tried this adjustment on the other
bands, but presumeably results will be similar. Seems 
that the Mark V does have a drive control after all. Its just
in a hidden menu instead of on the front-panel - Doh! 

73 de Mike W4EF............




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