i have been looking at and playing with the ver3 and ver3.1 of this radio for a few days,
stock mic is very poor,
the cartridge only makes about 5-6mv if you scream into it and there is no bass response,
don't let the thin sounding stock mic fool you, the radio's tx audio passband is wider than many cb's, a change of mic makes a world of difference,
the stock mic is moulded for either the dynamic cartridge or an electret condenser cartridge,
running an electret from the 4.5v up/dwn/asc pin4 works but it is a very noisy supply and not one id use, sending dc up the audio wire is one option, changing the mic socket is another option,
a cheap electret condenser cartridge sounds much better than the horribly thin stock dynamic cartridge,
there is an alc circuit in the mic preamp stage that limits maximum audio, adding a power mic brings average audio up and background noise up but you don't get much louder without internal alterations,
it sounds like the pumpy audio from kenwoods ts570 480 2000 when using an amplified mic, all background noise and no peaks with obtrusive time constants,
keeping the mic input down so at least some of your audio is below the limiter helps preserve some dynamic range,
imho the mic alc needs its time constants and threshold changing for best results,
some power mics work ok and some don't, the astatic 575 thumps out over 150mv when you key up which pounds the mic limiter causing a long delay of about 8 seconds before you get audio,
adding an attenuator to the mic output solves the delay, the moded 575 sounds much better than the stock mic,
also tried the kenwood mc80, theres no alc pounding delay but it has too much bass imho, a series polycap about .022- .033uf cures that issue and makes the mc80 sound about 10x better than the stock mic,
fm receive sensitivity is good for a cb but audio is too bass heavy/muffled to my ears, some locals like the wooly fm receive and some don't, it should be easy to fix with a couple of cap changes, i can't fix peoples ears,
ssb receive
,
this IS the main issue, some people say turning the rf gain down makes it sound ok but i don't agree,
the ssb agc timing is screwed up,
i will change the ssb agc time constants, hopefully this will stop strong stations popping and farting the receiver and minimise the s-meter jumping around like a mod meter,
i have the feeling that there is something else not right with the ssb receiver that fixing the agc won't cure but first i must fix the agc and see what my ears tell me,
am sounds acceptable so long as you lose the stock mic but its no out of the box screamer,
i don't see why it can't be made to swing like the other exports using irf520 finals if thats your thing, it uses very similar circuitry,
ssb tx is pretty good if you use a decent mic,
frequency stability is decent for a cb radio, not a lump of driftwood like magnums ect,
i can hear the inverter squeeling but thats not unique to this radio and many people won't notice it
i bought my anytone for experimental purposes
