Richard Clark Inscribed thus:

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.

Hi OM,

What you call fluorescent, I assume, must mean a small NE2 neon
indicator bulb which would be suitable to what you describe.

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.

It is going to be an indication of "something."


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

Within close proximity (about 3 to 5 times the wire separation), you
still have a sense of each wire. Further away, there is so little
difference in distance to either of them, that they both add with
cancellation.

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.

This must be the cobwebs you speak of. Other than LEDs (and I think
you would have specifically said so if your indicators were these),
lamps have no sense of current direction. Example, what would happen
if you reversed the plug to your table lamp? Would it suck light?
Have you ever put in a fluorescent bulb with the wrong polarity?

73's
Richard Clark, KB7QHC

I have vague recollections of a reflectometer using diodes, lamps and
300ohm twin feeder. Maybe in an old copy of Radcom...

73's
--
Best Regards:
Baron.

When I feed twinlead, seems I might use a small fluorescent bulb to
show how it's doing.
....[snip]....

See:

"The Eyes Have It; Making S.W.R. Measurements with the Twin-Lamp"
on page 50 of the October, 1948, issue of QST.

"The 'Coax Twin-Lamp', A Simple S.W.R. Indicator for Solid Line"
on page 25 of the November, 1948, issue of QST.

"Measuring Center Impedance of Antennas with the 'Twin-Lamp" on
page 67 of the May, 1950, issue of QST.

"Old Reliable" on page 67 of the April, 1958, issue of CQ.

--W0PBV.

--
-- Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member & Certified Instructor for Rifle, Pistol, & Home Firearm Safety
Also Certified Instructor for the Kansas Concealed-Carry Handgun (CCH) license