"Owen Duffy" wrote in message
...
On Tue, 11 Oct 2005 16:32:59 -0500, "Steve Nosko"
wrote:

[ clippers active...]

Owen,
Though this is not antenna talk...

Thanks for the confirmation of my half experience, half
judgment-based-on-knowledge based understanding.


Unfortunately, there is a growing common belief that unless the ALC
meter is high upscale, then the rig isn't being talked up enough (the
dumbing down of ham radio). snip... My thought is that if you want
audio compression, use a speech processor, not the ALC.

Interesting misconception. I'll remember this when I find that some
clarification is needed on ALC.
A good explanation "tool" is to say that the ALC "meter" deflection is an
indication of how much over drive you are trying to give due to too much
audio. I understand that it is an indication of the gain reduction being
applied to keep the PEP at the design max. If it is done correctly, it
should provide no compression effect at all.



Mentioning speech processors. A correctly adjusted speech processor is
proably better protection against overdrive than depending on ALC
alone. The peaks are contained (clipped) and the distortion products
filtered off, before getting near the PA which does not have effective
post filtering for clipping distorion.
Owen
--

I'd be careful in saying it this way because it appears to connect the
compression concept with the over drive concept and they are independent
concepts. The purpose of ALC is to set the proper PEP level (highest, but
not "too much") and the purpose of compression is to improve "talk power /
intelligibility" by increasing the average envelope power ( AEP ?) while NOT
changing the peak (improve peak-to-average-ratio of speech).

73, Steve, K,9.D;C'I