On Wed., 27 Nov 2002 "Tom Branch" <tom@k4nr.org> wrote:
> Subject: [VHFcontesting] 6 Meter Antenna
>
> I'm adding a 6 meter antenna to my farm to play around on 6. I have two
> options: 60 feet in the air on my tower with 200 feet of coax, or at 25 feet
> with 40 feet of coax. The tower mount is clear in all directions--the lower
> height is not. I'm guessing the loss on the coax far outweighs the height
> advantage.
>
> Thoughts?
>
> 73 de Tom
>
> tom@k4nr.org
> http://www.k4nr.org
>
- - - -
Tom,
With 6 Meter F2 just about gone for this solar cycle most of your
6M DX will probably be via Es, M/S or AU, with most signals coming in at
a relatively high angle. A yagi at 60 feet will work well but with almost
3 db of coax loss, you will miss out on those weak signals. Remember that
the loss affects both receive and transmit.
I can speak as someone who ran a 6el yagi at 70' for solar cycle 22 and
the same antenna on the roof of our suburban Maryland (DC area) house at
the 30' level on cycle 23. At 30' the antenna looks into trees taller
than it within 70 ft in all of the main DX directions (NE, E, S, SW & W).
As far as F2 performance, with this antenna the 6M DXCC totals climbed
from 113 to 146 from Oct. 2001 to Oct. 2002. The DX was worked with a
single 4X150 running 200W max output. I can't say that if the antenna was
on the tower instead of on the 30 ft level that any new 6M countries would
have been worked.
If I had the choice that you have, unless you can afford much lower
loss coax over the 200+ ft run, I'd put the antenna on the roof.
If you can reduce coax losses, then put the 6 Meter yagi on the tower.
Users of the Magic Band are still hoping beyond hope that the December
solar flux shoot beyond 200 for one last shot at 6 Meter F2 DX. We
should know by mid-month if 6M F2 DX is history for this cycle.
73 de Rich - K1HTV
dz@voa.gov
|