At 04:38 PM 8/27/2012, N7CXI wrote:
IF amplifiers fed back some kind of ALC ramp to the exciter on
VSWR fault, then that would indeed be a valid use of ALC for those
purposes, assuming it was set up correctly.
With the help of GOOGLE, I found a few references:
" As soon as a anomalous conditions is met (e.g. the reflectometer
reports a load mistmach), the controller develops a positive ALC
voltage to reduce the drive to a safe level." (
http://www.astrosurf.com/luxorion/qsl-amplifier-solidstate2.htm )
Note - most amps use negative now.
"The purpose of the ALC circuit is ..." "... to reduce drive when the
amplifier's protective subsystem detects an out-of-limits condition."
( http://www.ab4oj.com/quadra/sshfamp.html )
"Should the amp be loaded into a high SWR, the ALC will reduce the
drive level to a safer level." ( http://www.kk5dr.com/Tuneup.htm )
"most of the new series of solid state amplifiers hitting the market
these days, require the ALC to be connected as it is an integral part
of their built in self-protection scheme" (
http://www.eham.net/articles/10183 )
OTOH, many modern amps have built-in protection circuitry that may
not need the ALC connected.
Anybody can test their own amp by disconnecting the antenna
connector while driving it to full output ;-) . That is essentially
how I found out about how useful ALC can be I when I blew up my amp
when a flaky antenna connection went south while operating RTTY at a
full 1500 watts output years ago
Jerry W4UK
On 8/27/2012 12:11 PM, Jerry Flanders wrote:
Many amps rely on that ALC connection to allow them to cut back
on drive in the event of a malfunction such as an intermittent
flaky antenna feedline. A momentarily open/shorted antenna could
be very bad news for some amps under normal drive.
Some argue that you don't really need ALC. I suspect those guys
never had an antenna disaster.
Good luck
Jerry W4UK
At 02:52 PM 8/27/2012, ROGER SCHMITT wrote:
Have a small amp that I want to use on the 1500 but do not see
any ALC output to connect to the Amp, however since the oiutput
is only 5 watts, is this a problem? I intend to connect the PTT
circuit to the amp for on/off control.
Thanks for your help.
KY4RS
rogschm...@yahoo.com
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