point dish angles that consider altitude

[i4tas]

I am trying to receive a satellite that is -0.7 degree look angle (elevation angle). I am wondering if anyone knows a tool that will use my antenna height as an input. I am wondering if a location on a hill could overcome the negative angle. Then the other issue would be the height of hills in between, from my estimates my desired location would net about 200 feet over the base terrain height.

It would be nice if the dishpointer website would show the los obstacle with negative heights for satellite below the horizon. Or use terrain data

 

[Mr Tony]

anything negative is below the horizon......no matter how high you put it

 

[i4tas]

Yes a pole would not do anything but mountains and hills might.
Living on the top of an island in the ocean broadens one's horizon, thus more satellites could be seen.
From looking at dish pointer I could drive about 35 miles and have an angle of 0.1, so I am not convinced yet.

 

[FaT Air]

According to http://www.ringbell.co.uk/info/hdist.htm at a height of 1000 ft the horizon is 38.7 miles away. What is the angle? entering 1000 ft base height, 0 ft receiving and 38.7 miles distance computed to a downtilt of .28° at http://www.terabeam.com/support/calculations/antenna-downtilt.php#calc

6000ft altitude = 94.9 miles = -.686°
close but think you're going to get above 8000 ft to get a bit of clearance above the horizon to have any chance at all.

8000 ft altitude = 109.6 miles = -.792°
There we go, got .092° above the horizon if our sat is at -.700° at the surface at your position. (I don't think this amount of clearance is sufficient, I'd go up enough to get a couple of degrees clearance, at least) This also assumes a perfectly spherical earth, which is not true, and no hills or mountains between you and the satellite. Especially, at the horizon.
approximation and should only be used as a guide. No guarantees or warranties are implied

 

[Anole]

Not sure how many 9,000 or 10,000 foot mountain tops there are you could live on,
...but wouldn't you be constantly sweeping the snow off your thingie?
... and if you're moving, could ya just move east and be done with it?

 

[Bongu]

You could always move to an airship tethered 10000 foot above the ground........

Sent from my Timex Sinclair using SatelliteGuys

 

[FaT Air]

Transcript of communications from Airship B.H. Quest (Below Horizon Quest)
12000 ft = 134.2 miles = -0.97 -.7 = .27° above horizon. Q too low for lock.
24000ft = 189 miles = -1.378° - .7 = the air is gettin pretty thin up here.
40k ft = 245.2 miles =-1.77 -.7 = hey, I GOT it, 1sum up-a da horizu, but iz week, Plz up sum moore LP N Oh 2, k-kold an gaw funnel vizshion. gaw zu ge hi heighter
: ... _ _ _ ...

Moral of the story - Move East, Not Up.

 

[mikekohl]

I once used a 14 foot mesh antenna on an offshore drilling platform in Alaska, to receive a C-band satellite that happened to be 0.13 degrees below the horizon. It was shooting out across water at sea level, and the dish was actually about 75 feet above the water. While the entire dish was definitely not illuminated, I would have to say that enough of the top of the antenna was contributing to allow a poor (but watchable) analog signal. It was very strange looking at the feedhorn from the back of the dish, through the mesh, and seeing that it was pointed into the drink, below the horizon...but still getting a picture.
One other thing to be aware of is that even on C-band, you will have problems with ducting of signals when weather conditions change. A real continuous problem when your elevations are less than 2 degrees, by my experience in Alaska. Nowadays you can hook up a free to air receiver, lock in a transponder/channel, and leave the quality meter displaying the signal. Very useful information can be deduced after analyzing a DVD recording of more than a few minutes' length.