|AO-40 S-band circular polarization|
First attempt at circular polarization - I just hung the helix on the standard dipole. This reduced fading caused by satellite spin, somewhat.
Next attempt at circular polarization - I replaced the standard dipole with the helix. This seemed to reduce fading even more.
This helix was wound around a 1 1/4" PVC pipe then I opened it up to around 1 1/2" - this is 10 AWG wire from Home Depot.
Same process used on this helix, but with 4 1/2 turns. Someone suggested I was under-illuminating my 90cm dish - they suggested that I needed 4 1/2 to 5 1/2 turns to fully illuminate the dish. This did not receive as well as the 2 1/4 turn above.
Same process used on this helix, but with 5 1/2 turns and testing on my 18" DSS dish. This worked much better than the 2 1/4 turn - I will try this same helix on my 90cm dish soon..
(c) 2002 KD4APP
Last updated: August 11, 2002