You could mount a SCREWDRIVER antenna either to the roof or maybe on a leg
of the antenna support structure if they have one for the regular FD
antenna!

"Bob Dixon" wrote in message
...
Our local fire station would like us to provide an HF station to be
operated by hams during an emergencies. They have offered to pay the
cost of this. We already have an VHF station there. The problem is the
antenna. It cannot be visible (or at least not be at all obvious; they
are allowing the VHF antenna on the roof now.). The most likely needed
band is 75/80 meters, for in-state communications. So we need high-angle
radiation, and a vertical does not seem to be a good choice.

The roof is metal, so putting an antenna in the attic will not work.
The building is a fairly large 2 or 3 story structure, and in the
country with no other buildings nearby.

Here are some ideas I have:

1, A horizontal loop, running all around the building up near the top,
but somewhat below the metal roof. Would likely be non-resonant,
although perhaps we could choose the length. Mount it on stand-off
insulators just off the wooden siding. Use white insulated wire and
paint all hardware white, to blend in with the white siding. Feed it at
some convenient point, perhaps with a 4:1 balun and then coax into the
building. Open wire feed would be better, but we cannot get that into
the building and down to the station. Use a coax antenna tuner in the
station. The SWR would not be good, but the losses of RG/8 at 75M are
not that high. Maybe we could use some kind of outdoor automatic tuner
directly connected to the antenna, but I don't know of any offhand.

2. Use the rain gutters as an antenna. I did this long ago in a house
and it worked fairly well on 40M. Bridge all the joints with copper
braid, painted white, to endure reliable connections. At one of the
corner downspouts near the ground, connect the center conductor of a
coax cable to the downspout. Bury radials extending out from the
building an appropriate length, in a 270 degree sector, and connect to
the shield.
I don't know if the gutters are connected to the metal roof, but if so
that might or might not rule out this approach. Use a coax antenna
tuner in the station. I know this is basically a top-loaded vertical
antenna, but the choices are limited.

Comments on both these ideas, and other alternative suggestions, would
be greatly appreciated.

73,

Bob W8ERD