[Elecraft] ALC overshoot

[Tom W8JI]

> An undershoot of ~ 20% for the first few seconds of 
> transmission on a
> new frequency might be an irritant but an overshoot or 
> aggressive fast
> acting ALC leads to spatter on peaks, this is very common 
> issue on the
> bands today
> An undershoot of  ~20% on peaks (it's less on my K3) is 
> negligible in
> terms of the receiving end signal strength and a small 
> price to pay for
> a cleaner transmitted signal.


I think overshoot on SSB is greatly overplayed in most 
radios. There are some truly bad radios, but even in them 
the overshoot is very short duration. It often won't even 
show a regular peak reading meter. It is generally a few 
milliseconds at most from a "cold" start with no ALC, and 
then it is gone until the next nearly zero ALC drop. The 
result from ALC on SSB is an occasional very short syllabic 
tic. A couple milliseconds of spit or tic once every few 
seconds is not a big deal breaker. The real annoying crud, 
and bands like 20 are full of it, is caused by improper 
loading of amplifiers, poorly designed amps, and overdriving 
amps. It's the constant spitting and sputtering that wipes 
out entire words that is damaging, and I don't see the real 
damaging stuff changing much with work on ALC systems.

There are also the occasional phools who get inside radios 
and crank the power limit controls up. I know this because I 
repaired the FT1000MP's of a contester, set the power pots 
back to 100 watts where the radio was about -35 dB PEP  on 
3rd order, and six months later when I was doing a filter 
mod to the same radios the power pots were back up to 140 
watts where the radios have -20 dB PEP on IM3.

Someplace between the two is probably a good compromise, but 
don't bank on 20 meters and other bands cleaning up if all 
the ALC's in the world were fixed.

73 Tom