David Hamilton Cox wrote:
I live in the Blue Ridge Mountains of Virginia, within range of
FM stations in Washington, D.C., Richmond and Charlottesville. I
can get reasonable reception, usually, of WPFW 89.3 and WCVE 88.9,
if I try various permutations of my dipole antenna placement to
fit the current atmospheric conditions or whatever it is. Reception
of WTJU 91.1 is problematic, with usually at least a little static.
I'm wondering if I can improve this with a better antenna and/or
a better tuner. I read the great discussion in this newsgroup
on this subject (see:
snip
-David Cox
Syria, Virginia

The answer is a yagi antenna.

Most "TV" antennas will work just fine, since the FM band is inbetween
channels 5 and 6, iirc.

Depending on your distance from the stations in question, you want an
antenna that would give you at least good quality reception from TV
stations radiating from the same area. Keep in mind that many FM
stations are *lower* power than the typical city based VHF TV station,
so you may need a bigger antenna = more gain.

A preamp on the pole with the antenna is fine, assuming you have a
signal to amplify. FM works on a principle called "capture ratio" (iirc)
which briefly stated means that if you get enough signal above a
threshold it is quiet and clean.

Use a good quality 100% shield coax down from the antenna.

The higher up the antenna is, the better.
The higher above surrounding solid surfaces (roofs etc...) the better.

Ground the antenna (mast) to a good outside ground for lightning
protection.

Use stainless hardware if you expect it to be around for more than 5-8
years...

There's also goo used by the cable and phone people (and sold in
electrical supply houses) that is sticky and like a sort of putty/tape
that works wonders for water/weather proofing of connectors and other
electrical junctions on an antenna.

The LONGER and bigger the antenna, the greater the number of elements,
the more gain it will have...

You can of course build a purpose build homebrew yagi antenna just for
the freqs of interest which will be smaller and have fewer elements, and
maybe more gain in the FM band... check the ARRL antenna handbook for
that data or any Amateur Radio Handbook for general antenna building
ideas... or your local ham radio club. :- ) (it will last longer too...)

Any yagi will have a good "front to back ratio" meaning it has gain off
the front, and a null off the back, but the sides are pretty much "0"
gain, about the same as a little vertical would be, so you should have
no problem with the much stronger local stations, unless there happen to
be fairly high power stations in the direction you are pointing, and the
ones locally off the back are not very strong in the first place... but
that is what an antenna switch is for - to go from ant A to ant B - your
local dipole to the yagi.

Unless merely getting up in the air will do the trick, then a silly
vertical is pointless. You can test the idea by going up on the roof
with a portable FM or to a nearby hill with the car... that should give
you an inkling if the stations you want will come in with just adding
some height to your antenna...

Oh, if the stations of interest do NOT come in with merely height being
added to the antenna, and they are NOT all in the same direction, you
will need either multiple antennas fixed at the locations or an antenna
rotator.

_-_-bear