[email protected] wrote:
At 10/22/2009 19:15, you wrote:
I disagree that an audio delay board negates the positive effect of a
MICOR squelch.
...and let's not forget that many simply don't like ADMs. Ever try to
operate full-duplex with a quarter second delay on the repeat audio? Also
if the squelch chops the signal at all, an ADM set to a long delay can turn
those muted valleys into muted peaks, creating a problem with the squelch
where none existed before.
Bob NO6B
This is where the MICOR squelch shines. If you ever heard a UHF
repeater with a poor carrier squelch (kendecom comes to mind), no matter
how loose the squelch is set, mobiles in deep flutter chop up the
audio. The human brain is not as good at putting broken words together
where the break is a total dead absence. On the contrary, if the broken
word is bridged with noise, the brain can fill in the blanks, and a
severely broken sentence can make sense. While this problem is worse on
UHF where close spaced deep nulls can occur more frequently, the
situation exists on VHF as well.
Motorola did a lot or research on this subject during the Space Program
of the late 1960's. The result is the MICOR squelch many try to
replicate. If anyone that is interested in this subject would like to
learn more about the what the Motorola engineers take on it was, I
suggest you get a copy of a MICOR manual and read the theory.
Kevin Custer
