The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

I used to make a variable power mod on some of the Cobra and Uniden mobile radios using a transistor (rat shack part #TIP 120), a resistor, the RF gain knob or other comparible pot. Installation was pretty close to the same in them all!

I would like to do the same or a similar mod to my 139XLR....
does anyone have any ideas?

Also, if you know of any variable power and or super mod ideas for a
Uniden Grant... the old one with the MB8719 PLL... you can post it here as well! I have one of those I'm going to play with when I'm done with my 139XLR!

Well the a.m power VR pot is where you usily put or pull out , for the wires for the gain (power) veribal vr-8.

Do the modulation swing first ,
adjust vr-6 , and vr-7 for the most modulation swing
Forward on a meter you can get...

Thanks for the help! I already figured it out for the Grant and the 139xlr..

I now have 1/2 watt to 8 watt dead key on the Grant with swing up to 25

and 1/2 watt to 7 watt dead key on the 139xlr with swing up to 20 watts!!

The way I make the variable super mod with the rat shack TIP120 and a 100uf cap and a 100 ohm resistor and a variable pot such as the RF gain knob I end up with an input wire and an ouput wire! I wound up tracing the output path of the audio output to the collecter of the driver and tied into it! It works much like the way I installed it in the old Cobra AM mobiles!!!