Make sure that your converter has wide enough bandwidth.
I built a turnstile antenna but found it almost useless. If you have
time, check out the web for quadrafilar helix designs. I used this one:

http://perso.wanadoo.es/dimoni/ant_qha.htm

73, Kevin


JIMMIE wrote:
I want to built an antenna to receive weather images. I have done this
before using a simple dipole antenna. This time I was thinking of using
a pair of crossed dipoles and wanted to know if it would be best to
configure them as a circular polarized antenna feeding them 90 degrees
out of phase or as a turnstile antenna with both elements fed in-phase.
I have an old vhf aviation band converter that I think I can optimize
for 137Mhz use. I think the only thing else I need is a PC with a sound
card and the right software. This is the first time my daughter has
ever asked me for help with a GS project so I had better do this right.