I just put up an inverted vee that is cut for 80 CW.
I have a 250 pF series capacitor on the coax side
of the balun. A set of normally open relay contacts
are across this capacitor. When energized, the
capacitor is shorted out and I can operate on CW.
When non energized, I can operate on phone. There
is about a 300 kHz difference, which agreed with EZNEC.
The DC for the relay goes up the center of the coax
via RF chokes. The capacitor is one of those big
WWII transmitting micas I got at a hamfest (NOS
marked 1943 :-)
Rick N6RK
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com]On Behalf Of Cqtestk4xs@aol.com
> Sent: Friday, November 04, 2005 5:29 AM
> To: TOWERTALK@contesting.com
> Subject: [TowerTalk] 80 meter quad loops
>
>
> For the last few years I have been using four sets of rope
> supported quads..a
> two element facing JA, a two element facing VK, a two element
> facing SA, and
> a four element facing EU. All are tuned for the SSB part of the band.
>
> To operate CW contests, I lower the ends of the ropes supporting
> them screw
> in the extra pieces of wire, and raise them again. It's a pretty
> simple method
> but it doesn't solve the day to day excursions into the CW band.
>
> The loops are actually flattop delta loops so the pointed end
> faces toward
> the ground. The ends either have coax at the bottom or a rope at
> the bottom to
> keep it from blowing around.
> So what I would like to do is to put a relay and a coil at the
> bottom of each
> element to make the element resonant around 3725. They are currently
> resonant around 3775.
>
> Any idea of what kind of inductance would be required to make
> this happen? I
> know I would need to choke the relay wires. Would the old "coil it up"
> method work on the relay wires? Any special caveats on using this system?
>
> The system kicks butt on 80, but I would like the ability to
> switch back and
> forth between SSB and CW. Just using a tuner doesn't work, since the
> reflector isn't a very good reflector when you go down 250kHz. Any ideas?
>
> Bill K4XS
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless Weather Stations", and lot's more. Call Toll Free,
> 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|