[VHFcontesting] ft100 pwr reduction

[w8zn at comcast.net]

Folks,

This has been a favorite subject of mine for about 30 years. Most HF rigs have room and accessibility to low level drive that can be brought out to the back panel with SMA's and for HF operation a jumper can be installed. On a FT990 I set up for my dad, I used a relay that in the nomally open position, about +13 dbm was routed out the back. When the relay was energized, it routed the RF back to the fianl amp for normal HF operation.

TS-850's can have an RCA on the rear panel routed to an internal circuit that disables the finals when a DC voltage is applied. FT1000MP's have an internal switch.

For FT100's, you can reduce the drive via a menu (same with the IC706) and you can further reduce the output by lowering the "tx gain" settings. The problem comes in when it's 3 AM and you've be roving for 12 hours and seeing 4 lines in the middle of the road and you forget to reduce the power when QSYing from 2m to the microwaves, been there, done that, have MANY smoked devices to prove it!!!

Using ALC voltage to control the output IMHO is NOT the way to go. Some rigs still can spike the output due to R/C time constants when tx is first applied. DEM has a nice unit that will take up to 25w continuous and give you a low level out, it has RF sensing and hard keying. 

In my current rover setup I use a FT100 for 6, 2 and 70cm. I have the power turned down on 10m to drive a transverter for 222. I use a second FT100 with the 2m output set at 1w to drive 903 and above. This has two advantages, first, I never have to touch any drive levels during the contest. Second, having a separate rig for 903 and up enables a second operator to operate or yo can use the lower 4 bands for coordination of Q's above 903.

Terry