RM KL203-P

[Holydvr]

Nothing was burned up trace wise. At least two of the original mosfets had actually blown out, but they popped the side out and did not damage the board (thankfully!)

Shadetree, I had read (I dont believe everything I read though) on the defpom forum that the best replacement is the 13n10. I just figured the worst thing I could lose would be 9.99 even though I would only potentially fry four of the 20. I do not have anything else to use them in is why I say that. I just dropped them in, and I was seeing about 85 watts PEP on a whistle on SSB. This was with the radio turned down to 8 watts output PEP at the time. I have since turned the radio back up to 12-13w peak. I would have to measure the output again now due to that change. I can only be happy with the results overall, especially with the mileage I have gotten thus far.

 

[Holydvr]

Probably does not matter, but I was using a 100w Bird slug in a Bird 4391M meter to measure the peak power.

 

[aeromojito]

I would love to know what the power output is with the 13n10 replacements.

I added an attenuator to mine. It's a pi attenuator that cuts the input in half. My meter won't measure peak or PEP correctly but the deadkey is 30W with 4W input. I'm still having issues with oscillation but I think the Tram 3500 antenna is to blame for that. I'm going to try some ferrites and different jumpers when they get here.

 

[aeromojito]

I received my order yesterday. I tried ferrites on power and coax cables with no change. The 30Mhz low pass filter did the trick. SWR with the amp on is good on all 40 channels.

 

[ForestRunner98]

Awesome...enjoy the heck out of it!!!

 

[aeromojito]

Here is my 1/2 power mod on a KL203 (not the P) The input trace from the relay to the transformer is cut. An 18 ohm 3W resistor is in series. On either side of the 18 ohm resistor is a 300 ohm 1W resistor to ground. This gives a deadkey around 30W from a stock 4W radio. It was 60W before this mod. The modulated power reading doesn't mean much from my old second hand Dosy but it is a good reference. The radio keys 4W and swings to 8W. With the KL203, it keys 30W and swings to 70W.