[Elecraft] Power Amps and AGC

[Paul Christensen]

> 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