Posted by
P.B. Christensen on
Dec 01, 2008; 8:13pm
URL: http://elecraft.85.s1.nabble.com/VGA-cable-beware-tp1595397p1600413.html
> Your research is not complete, if you actually meant ALC. Yaesu's Quadra
> uses ALC as an emergency shutdown method to protect the amp in emergency
> situations. It is REQUIRED.
That's a poor RF design strategy. If a SS amp is so sensitive to input RF
drive level that it requires feedback from the exciter (of all brands) to
protect itself, then the amp should also be smart enough -- and fast
enough --to know when it's being overdriven.
Think about it. Yaesu is relying on a complete unknown from a transceiver.
While they specify the use of ALC from the transceiver for use with their
Quadra amp, they have no idea about "Brand X transceiver's" ALC response
time. A ca.1969 Heathkit HW-100 has an ALC circuit for connection to an
external amp. Are we to assume that a 40 year-old transceiver will have
adequate ALC dynamics as do some (but not all) of the modern transceivers?
The only time that ALC could possibly make any sense is to use a like-brand
amp and transceiver (e.g., Yaesu FT-2KD with the Quadra). This allows a
manufacturer of both the rig and amp to satisfy the proper ALC "meet me
point."
Paul, W9AC
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