Hey Bill,
Your comments about construction, location, etc., are right one, based on my experiences here. I actually move from one side of the house to the other depending on whether passes are to my east or west.
A couple of other things affect the performance I'm getting, too. One of the most important is that my decision to continue using a handheld antenna means I have less than six feet of coax from the radio to the antenna. I'm still getting some loss, but not nearly as much as I'd get by putting antennas in the attic and running much longer feed lines to them. Another is a little trick K4DLG in Florida passed along to me a while back.
He has a log periodic for HF, and the coax runs from the antenna feedpoint along the main boom to the back of the antenna before heading down to the shack. Taking that lead, he did the same thing with the Elk he bought. Doing so mitigated any significant changes in SWR due to moving the antenna around while hand-holding it during a pass. I tried it here and have observed the same thing. For me, at this location (inside or out), 8 degrees of elevation was the best I could hope for with the Arrow I had. In all the months I used that antenna, I made only a few contacts when a given satellite was below 8 degrees here. When I started using the Elk, that "bottom line" immediately dropped to 4 degrees. And when I tried K4DLG's suggestion of running the feedline parallel to the boom, the 4 degrees dropped to 3.
And, as you point out, depending on the location and relative path of a given pass, I can work even lower and make contacts, as I have with some stations in Europe on AO-7.
All of that being said, I also still lose the satellites due to obstruction, as you have observed with your Arrow. When it comes to the FM LEO satellites, only the ISS transmits back to us using more than milliwatt power levels. I know that AO-51 is capable of 1 watt or more, but it generally is not configured to transmit at those levels. Drew or someone, please correct me if that statement is inaccurate. The published stats on AO-27 report a nominal output of 500 mW, and SO-50 is reported to operate with a nominal 250 mW output. I believe both of them also use quarter-wave vertical antennas, which are 0-gain.
Given those power levels, it doesn't take much to begin affecting reception, especially for handheld stations. From here at my home, that quarter of azimuth from 90 degrees to 180 degrees is my worst. For really consistent reception in that part of the sky, I need upwards of 30 degrees elevation when I'm standing outside at ground level. On the second floor of the house, I get reception good enough to facilitate contacts with about 15 degrees of elevation at azimuths from 90 degrees to about 130. I still need close to 30 from azimuth 130 to 180 no matter where I try to operate from - in the yard or upstairs.
I hope you're able to come up with a solution for your location that works even better than you expect!
73 to all,
Tim - N3TL
-------------- Original message from Bill Dzurilla billdz.geo@yahoo.com: --------------
Tim, Yes, your QSO with F2IL is becoming famous, congrats. I think the performance of indoor antennas must be heavily dependent on the location of the shack and the construction materials used on the house. I moved my Eggbeater and ground plane to the attic from outside and noticed a sharp drop in performance. Also tried the Arrow here inside the shack and it did not do too well. And noticed that, even outside in the yard with the Arrow, I lose the sats at low elevation, when they drop below the level of nearby roof lines. On my DXpeditions to Swan Island and Jamaica, where there was unobstructed view over the ocean, I could easily make contacts with less than 1 degree of elevation with the same HT and Arrow.
73, Bill NZ5N
--- On Fri, 4/17/09, n3tl@bellsouth.net wrote:
From: n3tl@bellsouth.net > Subject: Re: [amsat-bb] Re: Homebrew Elk-style 14/435 mhz log periodic for
sats?
To: "Joe" , billdz.geo@yahoo.com Cc: amsat-bb@amsat.org Date: Friday, April 17, 2009, 10:19 PM Bill and all,
Joe is right. F2IL gave me a 569 report on AO-7 Mode B Thursday evening - and I was hand-holding my Elk on the second floor of my house, pointing it to the northeast at a spot on a windowless wall. When we worked, AO-7 was at roughly 3.5 degrees elevation here.
I wish I had decided to try these low-angle passes months ago!
73 to all,
Tim - N3TL -------------- Original message from Joe : --------------
You'd be amazed at what you can do with an indoor
yagi also..
My first 2 meter ant was a 3 ele quad on a photo
tripod that sat right
next to me on the floor in the shack,
Joe WB9SBD
Bill Dzurilla wrote:
Are there plans anywhere for a homebrew version of
the Elk duo bander? After reading through the prior thread about the poor performance of Eggbeaters and other omnis, I'm ready to risk the wrath of my Homeowners Association and put up
a small beam.
Or, anybody have an Elk for sale?
73, Bill NZ5N
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