On Mon, 31 May 2010 15:20:03 -0700, "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.


I have an old '58 copy of the ARRL handbook, and page 534 has the
"Twin-Lamp" tuning indicator for balanced line. It consists of a
couple of low-voltage flashlight bulbs wired to a short piece of
balanced line to insert into the transmission line.

Solder the tips of two flashlight bulbs together, wire that tip joint
to the short length of balanced line, and wire the bulb shells to the
line, too. Insert the device into the transmission line for tuning.

Fire things up. For minimum SWR, the bulb nearest the transmitter will
be bright, the bulb nearest the antenna will be dark. Or if the two
bulbs are glowing with the same brilliance, you have high SWR.

Bob
k5qwg