On 05/31/2010 03:51 PM, Bill Baka wrote:
On 05/31/2010 03:39 PM, Fred McKenzie wrote:
In ,
wrote:

Memory has usual cob webs. Help clear it.......

When I feed twinlead, seems I might use a small fluorescent bulb to
show how
it's doing. If a small fluorescent bulb will do this, do I just tune for
"max smoke" while holding it near the twinlead? Can't recall if a small
flourescent bulb will do this or not.

If radiation is cancelled, not sure how it would fire.

I vaguely remember we used to use twin lamps, wired backwards for this
purpose. One way you had SWR on one side; the other way you had SWR on
the other side. Neither light being lit meant good SWR.

RB-

My cobwebs are probably worse than yours. As a teenager back in the
50s, I used a "Full Windom" antenna (off-center-fed-dipole) fed with 300
Ohm TV twin lead.

The SWR measurement circuit I used probably came from an ARRL
publication. It consisted of two 6 Volt dial lamps connected to each
end of a section of twin lead. I think it was two or three feet long.
The whole thing was taped to the transmission line. There was a
connection at the center of this on one side to one side of the
transmission line.

As I understood it, one lamp was supposed to glow and not the other. I
think both of mine glowed, but one was definitely brighter. Of coarse I
did not know what I was doing and had no real understanding of SWR. I
made contacts, so never worried about it!

Try this.. I had an Ampex tube amplifier driving a high voltage
transformer and as the music danced (in my head) the patterns were
dancing to the same beat. I just drove the input of the Ampex with the
output audio line. Yes, that was in the 70's and yes we were all stoned.
I don't think that anyone else tried that combination, but it was way cool.
Bill Baka

Using a fluorescent tube, I would expect it might glow at points along
the transmission line where voltage was high and extinguish where
voltage was low. With a low SWR, there would be no high voltage points.
Or maybe no nulls?

Fred
K4DII

Whatever it was it was sure pretty and tube had ripples from both ends
that we could just watch. You would almost have to see it to believe it.
Kind of like visible standing waves going the length of the tube.
I think that kind of thing would kill any new solid state amps.
Bill