[amsat-bb] Inverted-V turnstile idea

Jonny 290 jonny290 at gmail.com
Fri Feb 28 11:50:22 PST 2014

I had an idea pop in my head for a simple turnstile antenna, and am not
finding much info on what I want to do via Google searches I wanted to
bounce this off the list and see what people think.

My idea consists of three main points:

-Antenna elements being conventional (non-folded) inverted V dipoles,
tuning the length for resonance and angle to set at 50 ohms each
-1/4 wave 50 ohm phasing line between the sets of dipoles
-Feed via DK7ZB match using a 1/4 wave paralleled 2x75 ohm line section (37
ohms), transforming the 25 ohms back up to right around 50 ohms for final

This approach would give the following advantages:

-Lower SWR than standard 75-ohm parallel turnstiles
-Dipoles could be individually tuned via direct 50 ohm feed during
-DK7ZB match is constructed out of inexpensive 75-ohm coax
-Phasing line length would only affect phase, instead of phase and

My main question, though is: With dipole elements canted down roughly 35
degrees from vertical (what I'm ballparking to get them down to 50 ohms),
am I going to see noticeably degraded performance, especially regarding the

Thanks for any tips or discussion!


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