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![]() "Short Wave Sportfishing" wrote in message news ![]() Based on yesterday's GPS discussion, I tried a little experiment today using an Yaesu FT-726 satellite communications transciever to monitor signal strengths on the L band navigation signals for GPS satellites. I picked four satellites to monitor - one from Block II, one from Block IIA and two from Block IIR. This gave me a decent sky area to work with with one at polar orbit and the other three at different declinations and acensions to the horizon in approximately 12 degree segments. It was interesting in that the navigation signals were fairly consistent until I got to the last two towards the horizon - the signal strength was significantly reduced as compared to the sats at higher acensions. I need to do some more comparisions with other satellites, but I'm wondering if there isn't something to this latitude thing I've been ruminating about for the past few years. Not to be a wise-ass, but isn't that what you'd expect? :- I have a satellite dish pointed at a bird parked at 61.5ºW over the equator. Dish Network swore that I would not be able to see that bird, and wanted to give me the HD package that was on 129º. The one at 129º does not carry NESN in HD, which was my whole reason for moving to satellite tv in the 1st place. My main dish is pointed "up" maybe 45º from the horizon. I get strong signals off those birds no matter the weather. The NESN dish however, is pointed almost horizontal (5º if memory serves), and is subject to "rain fade" and other glitches. I'm not concerned since baseball is a fair weather game, and it doesn't rain here from May thru October. I want my Sox in HD. So, my point of this whole drawn out story is, YES, the signal will degrade as you approach the horizon. The greater angle adds more atmosphere to interfere with the signal. --Mike |
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On Tue, 6 Jan 2009 19:12:48 -0800, "Mike" wrote:
"Short Wave Sportfishing" wrote in message news ![]() Based on yesterday's GPS discussion, I tried a little experiment today using an Yaesu FT-726 satellite communications transciever to monitor signal strengths on the L band navigation signals for GPS satellites. I picked four satellites to monitor - one from Block II, one from Block IIA and two from Block IIR. This gave me a decent sky area to work with with one at polar orbit and the other three at different declinations and acensions to the horizon in approximately 12 degree segments. It was interesting in that the navigation signals were fairly consistent until I got to the last two towards the horizon - the signal strength was significantly reduced as compared to the sats at higher acensions. I need to do some more comparisions with other satellites, but I'm wondering if there isn't something to this latitude thing I've been ruminating about for the past few years. Not to be a wise-ass, but isn't that what you'd expect? :- I have a satellite dish pointed at a bird parked at 61.5ºW over the equator. Dish Network swore that I would not be able to see that bird, and wanted to give me the HD package that was on 129º. The one at 129º does not carry NESN in HD, which was my whole reason for moving to satellite tv in the 1st place. My main dish is pointed "up" maybe 45º from the horizon. I get strong signals off those birds no matter the weather. The NESN dish however, is pointed almost horizontal (5º if memory serves), and is subject to "rain fade" and other glitches. I'm not concerned since baseball is a fair weather game, and it doesn't rain here from May thru October. I want my Sox in HD. So, my point of this whole drawn out story is, YES, the signal will degrade as you approach the horizon. The greater angle adds more atmosphere to interfere with the signal. I knew there would be some attentuation, but I didn't expect quite that much. And this transciever is fairly sensitive - I used it for ultra low signal work like moon bounce, meteor scatter and once bouncing a signal off an airplane. I'll have to dig out the oher antenna today seeing as how we're in the middle of an ice storm for some further experiments. I think I'm also going to do a hard count on what SVNs are in the sky and which ones for a few days. I don't know what I'm trying to prove other than I'm bored. :) |
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