Turnstile construction issues

1

I am currently in the process of building a 435 mhz turnstile based upon the plans of I6IBE.

435mhz-satellites-turnstile-antenna-tb1big

I have however run into some problems with the construction and specifically the distance between the active elements and the reflector.

I am trying to make this out of 32mm pvc pipe and i want all cable arrangements to stay inside the pipe and be terminated with a N connector at the bottom.

Using I6IBE measurements with a 13.8cm distance the reflector will end smack bang exactly where the balun/phasing line is, giving me next to no room for mounting the reflectors through the PVC pipe.

How important is 13.8cm which is 1/5th (?) the wavelength of the desired 435.500 mhz center frequency.

Any good reason why you cant use 1/4 wave at 17.2cm or even a 1/2 wave at 34.4cm?

Jomjom79

2

When building these, the distance to the reflector can be used to tune the frequency and impedance. I suggest building it so the position can be adjusted while measuring with a SWR meter or VNA/SNA to it’s final position.
You can check the Vinnant TUR435 and the last page of its manual.

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