> 2. use the SWR alarm relay to apply cutoff ALC voltage to the exciter; this
> method protects the amplifier's relays, so it's better than just de-keying
> the amp.
I must have misread the original problem.
I thought that the coax between the exciter and the amp shorted.
In this case, the VFD or other type alarm relay must be inserted
at the output of the EXCITER. Why fool around with ALC? Just run the PTT
line through the VFD. The exciter will unkey when pre-set VSWR is exceeded.
A VSWR alarm inserted in the OUTPUT of the amp will protect the amp, but
if the short is in the input, there will be no power out of the amp to activate
the alarm.
I use the VFD at the output of my transceiver, and the P-5000 at the output of
my amp. Sitting side by side, they tell me all I need to know about power out
of each box, and cover any failures or boo-boo's in the heat of battle.
R.F. Applications make extremely fine products; Bruce and the gang are
top-notch folks that are as near as your phone or computer when you have
a question. When an improvement to a product is made, the customers are
notified, and invited to send their units in for upgrade for low/no cost. This
company is truly a breath of fresh air. If you think the VFD is ugly, get an
expensive box and put it in there!
A word about accuracy....do not forget that measurements on 160 meters
with a Bird using a 2-30 mhz slug are not accurate...the readings are several
percent low. You need a slug that covers 1.8 mhz for the Bird to be within
specs. Not true with the R.F. Apps. boxes.
(((73)))
Phil, K5PC
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|