Regarding ==>
From: topband-bounces@contesting.com
[mailto:topband-bounces@contesting.com]On Behalf Of Ken
Sent: Sunday, July 18, 2004 10:41 AM
To: Topband
Subject: Topband: Switch for 160 meter antenna
Hello,
I am building a 160 meter vertical antenna, and perhaps incorporate
a 80 meter antenna within the same structure.
I would like to switch out a top section of the of the antenna by
means of a switch to break a connection leading to the rest of the
above antenna circuit.
I could easily do this with a relay, but I don't want to rely on any coil
failures either due to voltages drop out or weakness of the coil of the
relay.
What I would like to fine if possible, a type of wiper or knife like
switch that can be activated by a servo or similar type mechanical
devise.
Does anyone know of such a switch, and where to fine it?
Thank you,
Ken
K3YI
==============================================
Several things come to mind using sliding metal collars or coaxial tubes
with spring-finger-stock contacts (like the coil-shorting structure in a
screw-driver-antenna) that could be mechanically positioned to connect/
disconnect the various sections.
The mechanical driver could be:
- pulley-rope driven where the conducting collar has enough weight to allow
gravity to position it across the junctions with rope pull-back
disconnect.
This would be external to the conducting sections and could jam during
freezing WX if rainwater was present in the sliding gap.
- again a sliding collar with spring-finger-stock inside the vertical pipes
and
held in position in the upper-section by a spring. A rope exiting from
the
bottom could pull the sliding tube-contactor down to connect the sections
together. This would be a weather-proof installation and most likely free
from frozen water jamming.
- a pressure or vacuum driven plunger - or a motor-driven screw - to
position
an internal sliding switching collar or a coaxial combination of a
finger-stock
lipped-pipe receiving an insulator-led section of smaller conducting
tubing. The
insulating guide section could be a section of hard-wood stock boiled in
paraffin
or Teflon partially inserted inside the sliding contact.
73 de Dick - W7WKR
Stehekin, WA
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|