On Tue, 25 May 2004 16:12:05 GMT, "Henry Kolesnik"
wrote:
Before it came down my 20 meter antenna had a SWR approaching 20:1 and I was
running a Collins 30S-1 and no tuner!. I did that for several years and
would be still doing if the roofers hadn't destroyed ~130 ft. dipole. One
of these days after my back improves I'll put another one up.

Hi Hank,

I used to teach this Collins equipment in the Navy. I presume yours
had a finals tuning circuit still in it? Hard to imagine it
otherwise.

Tubes are different from transistors only by approaching the Source Z
with an inverted ratio of transformation. Ever hear of plate
resistance? It is literal resistance. Ever see a plate glow when
under the stress of hi SWR? It is literal heat. The same heat is
generated irrespective of it being explained by wave mechanics or
lumped equivalent circuits. Choose the model you are comfortable
with, and then tackle the SWR if you care about efficiency.

If anything, tube sets prove the problem of reflected power through
your ability to directly observe the heat generated and experience the
cost of new finals tubes through their degraded life span. This stuff
is all rote teaching; and my students were given practical tests to
troubleshoot, tune, and repair against such scenarios.

I've had hands-on experience with this topic both academically and at
several benches - the sophistries that deny these points are amusing,
but remain amateur scribblings.

73's
Richard Clark, KB7QHC