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Old April 25th 15, 03:25 PM posted to rec.radio.amateur.antenna
highlandhamFrank highlandhamFrank is offline
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First recorded activity by RadioBanter: Apr 2015
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Default A Top Band 1/4 wave vertical?

On 24/04/15 02:43, Allodoxaphobia wrote:
On Thu, 23 Apr 2015 11:56:18 -0700, Oregonian Haruspex wrote:

How about a tethered helium balloon instead? This way you don't have
to worry about powering the thing. Bell wire will handle 100 watts all
day without turning into smoke.


Then (for a full sized Top Band vertical) you'd better be
prepared for some VERY SERIOUS static electricity issues.
(And, it won't be vertical. It'll be a "slooper", I believe.)

One Field Day we threw up a cross-valley long wire (running horizontal,
of course) and, after the violent static display made itself known
inside the Field Day trailer, several fellas got knocked on their asses
trying to get it disconnected and away from all the other gear and
antennas around the site. That sucker was approx. 2200 feet long.
(Could've gotten 100 pts for "Natural Power", I s'pose...)

The Colorado Rockies: Low humidity - steady breeze -- sure was exciting
for awhile!

Jonesy

================================
To the matching box (tuner if you like) attached to my twin-feeder
dipole I have added a 47Kohm carbon resistor from 1 of the feeder
connections to chassis (ground) to avoid static build-up ,since the
attached inductor inside the box is not grounded.
Of course this does NOT protect against a lightning strike .
The 47 KOhm or higher resistor does NOT affect the antenna matching.

Before adding the resistor I had a flashover (due to static build-up)to
the primary inductor connected to the transceiver input. Fortunately
there was no transceiver damage ,but the solar panels /wind generator
13.8V set voltage controller was knocked-out.
Since adding the resistor ,many years ago, no more problems.

The above shows that (for a home brew matching box of the E-Zee type) it
is important that the centre of the inductor connected to the twin
feeder is grounded , alternatively a carbon resistor in the 47-100 kohm
range connected to one of the feeder connections, is grounded.

Frank , GM0CSZ / KN6WH in IO87AT