From: Doug Scribner
To: towertalk@contesting.com
Subject: [TowerTalk] 80M Inverted V - CW and SSB
After completing my newest tower, 66 feet of Rohn 45,
I added an 80 Meter Inverted V @ 62 feet.
I'd like to find a quick way to switch between the CW and
Phone portions of the band. I know I could just set it for
SSB and then add a short section to each leg for CW and
that works for dedicated contests but is a little inconvenient
for everyday use.
Short of using a tuner are there any suggestions?
TU...
Doug – K1ZO
## Sure, use a fan dipole. Build one inverted vee for say 3820 khz..and
another one for say 3525 khz.
Join at the feedpoint. Spread the far ends apart by apex 1-2 feet. Then
you will have a dead flat swr
in both the CW and SSB portion of the band. Simple, flat swr on 2 x feqs,
and no stubs to mess with.
Use 10 ga wire...and they will each be really broad. All you are doing is
stagger tuning each inverted vee.
You could also use 3 x vees, cut to 3 x diff freqs..and tune the entire band.
## Or use a single inverted vee.....and cut it for 3650 khz....... then use
BIG ga wire...like 6 or 8 ga.
## For you folks with 80 foot and higher towers.... the shortened rotary
dipole works good too. Capacity hats,
aka.. T bars..that resemble a 10m ele..are installed half way out, or a bit
further on each side of the shorty dipole.
The balance of the loading can be done with a seco systems tornado drive. It’s
a motor driven pair of compressible
one quarter inch tubing coils.. made of plastic coated copper tubing. Uh can
be varied in a 2:1 ratio. Like 6-12 uh
per coil.
A simple 5 turn tubing coil is installed across the feedpoint.....and is the
helical hairpin. SWR is then dead flat from
3400-4100 khz. 14 db FS on dx signals.
Jim VE7RF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|