Here is a good web site for building a quadfilar helix antenna

http://www.qsl.net/kf4cpj/qha/

"Thierry" - wrote in message ...

This is to receive WX APT signals broadcast on 137 Mhz and sometimes to
listen to
the aviation band or work VHF (144 - 146 MHz - amateur allocation).
Should I select a discone instead of the helix ?
Are there any advantages of using a discone, or drawbacks, versus a
quadrifilar helix
antenna, except the price ?

Thierry


"Roy Lewallen" wrote in message
...
A discone antenna is a vertically polarized, broad bandwidth antenna. A
quadrifilar helix is a circularly polarized, relatively narrow bandwidth
antenna. About the only thing they have in common is that both are
omnidirectional in azimuth. A quadrifilar helix is a more suitable
antenna for receiving the circularly polarized, relatively narrow
bandwidth signals from a weather satellite.

Roy Lewallen, W7EL