I'm currently building a VHF APT image receiver for my vehicle, and need
a suitable antenna design that is rugged enough to survive the rigors of
being hit by hail and strong winds. It also needs to be relatively
compact because I need to fit other antennae on the roof too. I was
thinking some sort of helical. Anyone got suggestions of what would be
best? Thanks,

David

"David Findlay" wrote in message
...
I'm currently building a VHF APT image receiver for my vehicle, and need a
suitable antenna design that is rugged enough to survive the rigors of
being hit by hail and strong winds. It also needs to be relatively compact
because I need to fit other antennae on the roof too. I was thinking some
sort of helical. Anyone got suggestions of what would be best? Thanks,

David

David

I have some experience with APT imaging and antennas for NOAA satellites.
You can contact me at my E-mail address for more info and pictures.
I wouldnt be optimistic about being able to get good images with an
antenna that is permanently mounted above the top of a car.
Are you aware that Walter Maxwell frequents this news group? He has to
be the best source of guidance on APT antennas *anywhere*.

Jerry

"David Findlay" wrote in message
...
I'm currently building a VHF APT image receiver for my vehicle, and need a
suitable antenna design that is rugged enough to survive the rigors of
being hit by hail and strong winds. It also needs to be relatively compact
because I need to fit other antennae on the roof too. I was thinking some
sort of helical. Anyone got suggestions of what would be best? Thanks,

David

The Quadrafilar Helix (QFH, QFHA, QHA) is regarded as a good performing
antenna. Some web pages:

Dutch site for building your own (at 137 MHz - it will be tall).
http://www.kunstmanen.nl/antenna.htm

Steve Blackmore had a "how to" build QFA web page -- but it is currently not
up (you can e-mail him)
http://www.pilotltd.net/

Bill Sykes (G2HCG) and Bob Cobey (G0HPO)
http://www.askrlc.co.uk/

QFH - DIY (European site)
http://homepage.ntlworld.com/phqfh1/qfh_diy_guide.htm

g. beat
w9gb