One of the things I see that is different, as I have watched videos of the
bigger transmitters firing up, is that they can bring the driver stages online,
and have them drawing plate current, tune them, and then engage the final.
Obviously, there is not tx/rx relay for a plain transmitter. So, where does
that drive power go while the driver(s) are being tuned, and the final is on
standby? There are plenty of such videos out there that are exciting to watch!
FM of course, does not have any 'swing", so you crank the carrier where you
want it to be, and it just sits there. AM on other hand of course, is set for
about 25% of max carrier, and them modulation takes it up and down from there.
Based upon that description, when WLW was running a full 500KW, I'd assume the
engineer would set the carrier around 125KW, and then 100% modulation would
peak at 500KW.
Any way you slice it, that is a bunch of RF up the feedline!
Don N8ECH
In our case, we engage the tx as a unit, and then tune for appropriate
readings, and/or maximum smoke, lol.
On Monday, September 12, 2022, 03:19:34 PM EDT, Peter Voelpel
<dj7ww@t-online.de> wrote:
Yes, no difference, just bigger and more powerful.
73
Peter, DJ7WW
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Kim Elmore
Sent: Sonntag, 11. September 2022 03:36
Don Fox raises a question I've wondered about for years: how are these very
high power amplifiers initially placed in service? Today, we have VNAs we
can put in the palm of our hand, how is it done now and how was it done when
there was nothing but vacuum tubes? How adjustable are the PA output
circuits? It can't possibly be done the way we tune our puny 1.5 kW amps.
Kim N5OP
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