"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

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. :)