Couldn't find it/never heard of it.Same like PC-122 mentioned on HandyAndy webpage.
Mike
The way I do it is to put variable resistor inside the radio between mic socket and mainboard to adjust maximum input modulation level, so user can't overdrive
I did that paralel to C169 - as on EPT boards. Looked better on scope. Slight diffrence when listened on another radio.
Only diffrence is, that I used 100ohm resistor. Of course you can use variable, but 100ohm is just what we need. Higher resistance, less NPC efect. If went below 100ohm, it becomes distorted, so 100ohm for me was a sweet spot
To do it complete there is a need to remove AM limiter (r153 in TRC) and put 13.8V to final as in EPT-xxxx based radios. Than adjust AM power and modulation level to get nice, clean signal on the scope. The way I do it is to put variable resistor inside the radio between mic socket and mainboard to adjust maximum input modulation level, so user can't overdrive and power is set around 2W carrier. It works perfect.
Mike
Im real bad @ reading elec plans...
Even if do the mod as described in that diagram on the first page; you will still need to remove the AM limiter, and volt the final transistor. Oh yeah; and put a variable pot on the incoming mic wire in the mic preamp. Then adjust that pot with a scope for best waveform shape. Not exactly easy to do right. And if done wrong; it will sound like crap. Be real careful!
I know some will poo poo on removing the limiter (i dont care myself if i do) but i did in my 465 and i NPC RC modded the radio and it works well..
I have done the NPC MOD on one of my 465 that I sold a long time ago and forgot whrer I got it from either from Defpomʻs site or somewhere else. I had it DK around 1.5 watts and it would swing 12+. All I did was add a diode and resistor.
Thanx guys. Too complicated to do that Mod. Maybe Yanking the limiter would be my best bet but I also run SSB too so contemplating on it.
Mahalo james.....