[amsat-bb] NASA Helical Antenna Question

[MICHAEL WILLIAMS]

John (vk2fak), 


You said "Is there any details on the web about this type of helix, have never seen
it with a ring reflector in books."


I've also never seen a helix ring reflector design in any antenna books. My first home brew helix followed  AF9Y's design exactly from his site http://www.af9y.com/helix.htm which used a ring reflector. 


My second build did not use PVC boom (too heavy) or copper tubing (too expensive) but a 1 in. square metal boom and aluminum clothes line wire. I kept the ring reflector.


This is the first time I've seen two reflectors used. It would be interesting to discover who NASA's supplier is for this antenna and see the spec's.


Regards, Mike