Yes, that's exactly what I had in mind! So it very well may be a viable design, then.
-- Matt -jonny 290 On Fri, Feb 28, 2014 at 2:51 PM, Matthias Bopp <[email protected]> wrote: > Hi Matt, > > are you referring to a turnstile antenna like the one available from WIMO > here in Germany ? > > Please see the following link: http://www.wimo.de/download/ta1.pdf > > Best regards > > Matthias > > www.dd1us.de > > > -----Ursprüngliche Nachricht----- > Von: [email protected] [mailto:[email protected]] Im > Auftrag von Jonny 290 > Gesendet: Freitag, 28. Februar 2014 20:50 > An: [email protected] > Betreff: [amsat-bb] Inverted-V turnstile idea > > 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 feed > > 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 construction -DK7ZB match > is constructed out of inexpensive 75-ohm coax -Phasing line length would > only affect phase, instead of phase and impedance. > > 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 > polarization? > > Thanks for any tips or discussion! > > --Matt > KC4YLV > _______________________________________________ > Sent via [email protected]. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
