Batboard

Hi,
Not sure where to adress this but couldn´t find a better place for this question about the Super-Turnstile antenna also known as the Batwing antenna. My question is has anyone ever seen one used for LMR say on a repeater system?

Famously:

https://kd2sl.wordpress.com/2012/03/18/the-antenna/

One downside of the kd2sl antenna is that it is horizontally polarized as are all "turnstile" type antennas. Horizonal is normal polarization for TV broadcast and also for typical Ham fixed operation but not mobile. Cross polarization can cause major degradation, especially on higher frequencies and for mobile use. The issues are discussed on the link in the previous post. Also, this is a low band antenna and LMR repeaters are usually VHF/UHF.

If this is for ham radio you could run horizontal polarisation for mobile.

It was very popular years ago for 6m mobile, see:

http://www.macnaughtonart.com/halo.htm

However, I've never seen commercial LMR using H-pol.

Thanks for the informative replies. I see that the H-pol issue makes the Batwing antenna little useful in an average LMR antenna system. That´s probably one among a few good reasons for using the stacked folded dipoles antennas instead. I have a bunch of folded dipoles that I´m about to put into service (again) and in that proces I thought about building a Batwing antenna mostly for RF links which may also be possible. Question is if there´s an actual good reason for doing so as a beam antenna might be at least as effective if not even better for the job.

k2hz wrote: ↑

Sat Feb 06, 2021 6:18 pm

One downside of the kd2sl antenna is that it is horizontally polarized as are all "turnstile" type antennas. Horizonal is normal polarization for TV broadcast and also for typical Ham fixed operation but not mobile. Cross polarization can cause major degradation, especially on higher frequencies and for mobile use. The issues are discussed on the link in the previous post. Also, this is a low band antenna and LMR repeaters are usually VHF/UHF.

I chatted with the guys about that repeater...they seem to disregard that V vs H pol is a 20DB difference...The Batwing (NOT a Motorola design BTW) was designed for lowband TV because of the wide bandwidth needed (a typical lowband antenna would give maybe 5% bandwidth for 2:1 or less SWR. A Batwing does more like 10- 20% BW which at 54-88MHz was needed for the 6MHz signal of TV). It uses the concept of the slot antenna where the wings are fed in the middle and since most current flows in the outer ends of the wings, the middle is brought in to reduce windloading. Hence it looks like a wing on its side. Most lowband TV stations are now using CP or EP designs that can cover the 6MHz channel so batwings are no longer the favorite. For 6m SSB, they would GREAT....ATV on 430 really loves the wide bandwidth and H pol operation...but for FM, they are a waste of time to use. 6m rptrs have been quite common as well as lowband LMR rptrs (used to have to show a NEED for one but now its easy to get a license). 10m was same way in the 70s...had to show the FCC WHY a 10m rptr was needed. The rules changed in the 80s and allowed ANYONE with a General or above to put one on....(if only we could get certain rptr ops to agree to things like CTCSS on IN and OUTPUTS, put the CTCSS tone in the ID anad hangtimes no longer than 3 secs...but some folks are jerks and refuse to cooperate.)

Chris
"MOTOROLA, you may find better, but you'll NEVER pay more!!" (old Entergy saying)

That's why we have regional repeater coordinators. They are there to work out the stubborn operators of those repeaters causing problems.
Jim

HAHAHAHA!!! No they don't....the TX VHF FM Society has gone to crap...coordinating 10k splinters on 2m with 16K0F3 emissions!! Something the membership NEVER voted on...I'm a former BoD member (twice) life member since 1979 and former coordinator....NEVER got notified as REQUIRED by the bylaws of this.....Neither did several other Life and regular members...we are considering legal action now...
LA's group, the LCARC, has made changes to the bandplans without votes by the members....several rptr trustees are pissed and no longer consider the LCARC the coordinating group. Cant blame them...I had an issue when I lived in New Orleans...wanted to put a UHF DMR rptr on a 750 ft bldg downtown with a DSTAR on 12.5k away 60+ mile distance...the coordinator refused....YET, there was an ANALOG on the other 12.5k side of the DSTAR on ANOTHER downtown bldg top and it WAS coordinated...NOW WTH ??? I was Narrow band yet couldnt get coordinated but a WIDEBAND the other side of the DSTAR COULD??? BS!!!!
TX has been coordinating 6m rptrs in the 52.00-52.8MHz OUTPUT range.....again, never voted on/passed by the membership..I proposed in 97 Texas go to the -1.7Mhz offset....never voted on...yet this 1MHz crap was NOT voted on but is coordinated???
Yeah I have had talks with Riley Hollinsworth about this.......and other Society members/trustees.....its GONNA stop.....we have had enough....the Society QUIT publishing a newsletter, the meetings announcements are NEVER mailed (or EMAILED!) so they can get away with this kind of crap.....NO MORE.......I was involved with the NFCC and NFCB group....they fell apart because there was no national consensus. ARRL had screwed up 6m and 2m bandplans by IGNORING technical data.....and giving in the POLITICAL pressure from the VRAC..

Its all a joke now....