Hi,
Just wanted to say that I have just performed the (resistor) TX instability mod, as detailed on the QRPLabs website and it works.
I had an odd symptom where on key down you would sometime gets 2.5W (20m QCX) and then a second later on key down you would get 0.5W. There seemed to be no rhyme or reason as to which you would get or why. But the 10K resistor mod has tamed it completely. I'm writing this in case anyone sees a similar behaviour and wonders why.
Now I just need to work out why I'm only getting 2.1-2.5W, given I used to get about 3.1W with my first set of BS170s in the PA. These were changed out during the debug phase that saw me eventually replace all the BS170s, the MPS751 and IC3. I guess different batches of transistors may give different results.
I'll leave it for now as I think it has seen enough of the soldering iron for the time being!
Steve G0KYA
