Building a Turnstile Antenna for UHF

Building a Turnstile Antenna for UHF

I have been told by my VU friends that they can hear my signals on the satellite transponders, but I am not replying them. Due to my local conditions, I am unable to operate outdoors and my operations are restricted to vertical antennas as I do not have an antenna rotator. I have been able to have a few VU QSOs through the transponders at International Space Station and Tevel 7. I did miss many others because I could not hear them, while they were hearing me, as confirmed on our LEO Satellite Repeater Contact WhatsApp Group. VU2WMY had some time back suggested Turnstile antenna as a starting point for receiving satellite downlink. I found a detailed description by SP9ALI for 435.500 MHz, to be used for SatNOGS network.

Even though it is below the downlink frequency of International Space Station and Tevel 7 which I have been successful at so far, it is near the uplink of AO-91, which is 435.250. As this is my first attempt to homebrew a Turnstile antenna, I do not want to modify the centre frequency, even though I am using surplus 3/8 inch aluminium pipes instead of the 4 mm stainless steel rods which SP9ALI used. Today I have finished cutting the 3/8 inch aluminium pipes for the driven elements and reflectors. I have also cut the coax pieces for quadrature phasing. I am yet to figure out how to fix the driven elements and the reflectors at 3/8 lambda spacing as I do not have the 3D printed clamps which SP9ALI used. Planning to come out with an innovative idea using surplus material available in my store!