CPI CP2000 AM modulation limiter modification
Posted: Wed Feb 08, 2017 11:55 pm
CPI CP 2000 AM modulation limiter modification.
This mod got me from 80% mod (tops) to 110-115%
4 more watts PEP as well.
Communications Power, mod limiter, clip, cut, diode
make R232 higher in value.
R232 is at the top in this shot, above the red line (resistors in series)
I've wanted to figure this out for years. The board/soldering is very fragile on these radio's. I used solder braid and a small 25 watt iron.
Lifted one end of R232 (2200 ohm) and added another 2.2K, 1/2 watt in series with R232 as seen in the right of the third and top of the second. This gave a total of 4.4K.
I tried adding a 4.7K first but it went overmod and got choppy, so I lowered it to 2.2K. It was at %150 and was peaking past 20 watts though... lol
This mod got me from 80% mod (tops) to 110-115%
4 more watts PEP as well.
Communications Power, mod limiter, clip, cut, diode
make R232 higher in value.
R232 is at the top in this shot, above the red line (resistors in series)
I've wanted to figure this out for years. The board/soldering is very fragile on these radio's. I used solder braid and a small 25 watt iron.
Lifted one end of R232 (2200 ohm) and added another 2.2K, 1/2 watt in series with R232 as seen in the right of the third and top of the second. This gave a total of 4.4K.
I tried adding a 4.7K first but it went overmod and got choppy, so I lowered it to 2.2K. It was at %150 and was peaking past 20 watts though... lol