How does the Elk Dualband yagi work as a satellite antenna in a base setup when you are not elevating it? Is it better to mount it for vertical or horizontal polarization to get maximum coverage of satellite passes? Still trying to figure out the best FM sat setup here after some station redesign.
73s John AA5JG
John, here is an alternative often overlooked. Works pretty good for me on a mast.
http://www.antennas.us/store/p/229-UC-4364-328-Amateur-Satellite-antenna.htm l
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Geiger Sent: Monday, December 20, 2010 7:43 PM To: Amsat-Bb@Amsat. Org Subject: [amsat-bb] Elk dualband antenna experiences
How does the Elk Dualband yagi work as a satellite antenna in a base setup when you are not elevating it? Is it better to mount it for vertical or horizontal polarization to get maximum coverage of satellite passes? Still trying to figure out the best FM sat setup here after some station redesign.
73s John AA5JG _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
I'll add my two cents.
I've used the Elk exclusively for the last few months operating "portable" in my backyard (and while camping, etc). The Elk sits on a photoraphic tripod, and I use a little netbook computer to display the satellite plot and aim the Elk accordingly. I absolutely love the antenna, it assembles/disassembles quick, doesn't take up much space, and has more than enough gain to work all the FM and SSB sats in this configuration.
What I *have* noticed is that I do have to aim the Elk where the sat is. If I lower the antenna to horizontal, I notice a significant fading. That much is to be expected, so if you are in a situation where you can't elevate the antenna, just aim it up a certain number of degrees (maybe 15-30 depending on your horizon) so that it's close enough for low passes, and the high passes (where sat is much closer) should also work.
As for polarization, I've noticed that I get much better performance out of the Elk by rotating the antenna to match the polarization of the satellite at any given instant. I have the PVC mount swivels fairly loose, so it doesn't take much to flip the antenna back and forth a little to find the best match. When polarization is matching, I can have better than S8 sigs, and rotating the polarization 90 degrees will often decrease my sigs to S2 or below. So ... for a fixed installation, with fixed polarization, you'll likely encounter some deep fades in the passes, no matter which you choose. So far I've found that I typically use "almost vertical" polarization compared to less frequently using "horizontal" polarization, so if I had to choose between the two, I'd go vertical ... but it may not make much difference!
One thing I've seen on the lists has been the recommendation to add a pre-amp to the antenna. Typically people will do this with an Arrow, since it has separate VHF / UHF outputs so it's easier to config for preamp. Those that use this method report great results, since the preamp overcomes much of the signal loss on the UHF downlink. Since the Elk has a single dual-band output, you may have to look into duplexers to split out the UHF signal for the preamp.
Hope that helps! That all being said, I've been putting together an outdoor antenna system over the last few weeks (it's hard to sit in the rain with the Elk and the twin FT-817's!) ... new system is a 4-el VHF yagi and 15-el UHF yagi with preamps, on an az-el rotator. Initial testing seems to indicate that it works pretty well -- so I'm looking forward to staying dry during satellite contacts for a while!
73 de Dave KB5WIA / CM88
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Geiger Sent: Monday, December 20, 2010 7:43 PM To: Amsat-Bb@Amsat. Org Subject: [amsat-bb] Elk dualband antenna experiences
How does the Elk Dualband yagi work as a satellite antenna in a base setup when you are not elevating it? Is it better to mount it for vertical or horizontal polarization to get maximum coverage of satellite passes? Still trying to figure out the best FM sat setup here after some station redesign.
73s John AA5JG _______________________________________________ Sent via AMSAT-BB@amsat.org. 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 AMSAT-BB@amsat.org. 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
On 12/21/2010 4:40 PM, David Palmer wrote:
As for polarization, I've noticed that I get much better performance out of the Elk by rotating the antenna to match the polarization of the satellite at any given instant.
Absolutely! Even circular downlinks are more elliptical, and have a preferred polarity. The same principles apply on the uplink too!
See http://www.youtube.com/watch?v=XTqjQ9xIQQE for a 29 second demonstration of this effect.
73, Drew KO4MA
I like my Elk yagi also, as like mentioned, breaks down for transportation quite nicely. Attached photos are of my Elk yagi carry enclosure. Made from ABS plumbing materials. I store it in my truck toolbox, along with my HF coils in another ABS tube so they wont be damaged.
http://i863.photobucket.com/albums/ab199/W6ZKHJOHN/Vacation2009033.jpg
http://i863.photobucket.com/albums/ab199/W6ZKHJOHN/Vacation2009034.jpg
John W6ZKH DM06
________________________________ From: David Palmer dave@zdap.com To: Ted k7trkradio@charter.net Cc: "Amsat-Bb@Amsat.Org" amsat-bb@amsat.org Sent: Tue, December 21, 2010 1:40:27 PM Subject: [amsat-bb] Re: Elk dualband antenna experiences
I'll add my two cents.
I've used the Elk exclusively for the last few months operating "portable" in my backyard (and while camping, etc). The Elk sits on a photoraphic tripod, and I use a little netbook computer to display the satellite plot and aim the Elk accordingly. I absolutely love the antenna, it assembles/disassembles quick, doesn't take up much space, and has more than enough gain to work all the FM and SSB sats in this configuration.
What I *have* noticed is that I do have to aim the Elk where the sat is. If I lower the antenna to horizontal, I notice a significant fading. That much is to be expected, so if you are in a situation where you can't elevate the antenna, just aim it up a certain number of degrees (maybe 15-30 depending on your horizon) so that it's close enough for low passes, and the high passes (where sat is much closer) should also work.
As for polarization, I've noticed that I get much better performance out of the Elk by rotating the antenna to match the polarization of the satellite at any given instant. I have the PVC mount swivels fairly loose, so it doesn't take much to flip the antenna back and forth a little to find the best match. When polarization is matching, I can have better than S8 sigs, and rotating the polarization 90 degrees will often decrease my sigs to S2 or below. So ... for a fixed installation, with fixed polarization, you'll likely encounter some deep fades in the passes, no matter which you choose. So far I've found that I typically use "almost vertical" polarization compared to less frequently using "horizontal" polarization, so if I had to choose between the two, I'd go vertical ... but it may not make much difference!
One thing I've seen on the lists has been the recommendation to add a pre-amp to the antenna. Typically people will do this with an Arrow, since it has separate VHF / UHF outputs so it's easier to config for preamp. Those that use this method report great results, since the preamp overcomes much of the signal loss on the UHF downlink. Since the Elk has a single dual-band output, you may have to look into duplexers to split out the UHF signal for the preamp.
Hope that helps! That all being said, I've been putting together an outdoor antenna system over the last few weeks (it's hard to sit in the rain with the Elk and the twin FT-817's!) ... new system is a 4-el VHF yagi and 15-el UHF yagi with preamps, on an az-el rotator. Initial testing seems to indicate that it works pretty well -- so I'm looking forward to staying dry during satellite contacts for a while!
73 de Dave KB5WIA / CM88
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Geiger Sent: Monday, December 20, 2010 7:43 PM To: Amsat-Bb@Amsat. Org Subject: [amsat-bb] Elk dualband antenna experiences
How does the Elk Dualband yagi work as a satellite antenna in a base setup when you are not elevating it? Is it better to mount it for vertical or horizontal polarization to get maximum coverage of satellite passes? Still trying to figure out the best FM sat setup here after some station redesign.
73s John AA5JG _______________________________________________ Sent via AMSAT-BB@amsat.org. 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 AMSAT-BB@amsat.org. 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 AMSAT-BB@amsat.org. 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
participants (5)
-
Andrew Glasbrenner -
David Palmer -
John Geiger -
John Neeley -
Ted