In article , "rb"
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!

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