[amsat-bb] attic antenna

Thomas Doyle tomdoyle1948 at gmail.com
Mon Mar 7 16:38:06 UTC 2016


I have been using an inside antenna for many years. The rafters in the
attic made it difficult to install anything but a ground plane up there so
I converted an extra bedroom into an antenna farm. This enabled me to put
in beams for 2M and 70cm with a Yaesu rotor. I am able to copy beacons down
to the horizon. The house has vinyl siding so that might help. Older homes
with aluminum siding might have more problems. There are also special
"energy saving" shingles around that have a layer of aluminum embedded in a
conventional asphalt shingle, these might also be more of a problem. Like
you I also found that at my location I believe the performance of
the inside antennas is very close to outside antennas on 70cm and below
with LEO satellites. This is empirical data. It is also nice not to have to
worry about wind, snow, ice and rain or climb around on a tower to make
adjustments.. My antennas and preamps look like new.

I suspect that in the unlikely event we ever have another HEO satellite
or on frequencies above 70cm  the inside antenna might be more or a
problem. All my work with HEO sats back in the glory days used outside
antennas so I do not have any empirical data.

If the signal strength is high enough almost anything can work. I Think
about that every time I use my smart phone in an elevator to check my email.

W9KE Tom Doyle

On Sun, Mar 6, 2016 at 6:18 PM, Pete Parisetti <peteparisetti at gmail.com>

> Having read about some mighty satellite antenna installations in the attic
> - one in particular... - I wanted to run a few tests of my local conditions
> before going ahead with a similar project.
> I built a GP for 146 MHz using wire hangers (SWR flat across the entire 144
> and 430 MHz bands....), placed it in my attic and fed it with 45' of
> Ecoflex 10.
> On a dry day, today I could hear the FO-29 beacon from about 10 degrees to
> about 10 degrees. I find this extraordinary. I don't know if ther roof
> slates will attenuate more when wet (this may be a urban legend...), but on
> a day like today I think the difference attic/outside is almost negligible.
> 73 Pete MM0TWX
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Sent from my computer.

tom ...

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