Measuring dish elevation

**TiminMb** · 09-23-2005 12:28 PM

Can dish elevation be read off an inclinometer and be directly related to the elevation of a satellite? Or is there some focusing factor which this doesn't take into account?

**Iceberg** · 09-23-2005 01:22 PM

offset dishes are at 20 some odd degrees offf what a prime focus would.

So a 45 degree angle on a prime focus looks like 25 on a offset. That's why the dish can look like its aimed at a tree, or the house but you get a great signal

**Anole** · 09-28-2005 05:46 AM

Originally Posted by TiminMb

Can dish elevation be read off an inclinometer and be directly related to the elevation of a satellite?

That really got me thinking!
I have one. It has a magnetic base.
They're $2 to $5 for a cheap one. (and a cheap one is so much better than none!)

If you could clip it onto the flat back of your dish (like there's a flat space back there), you could take a reading, add in the offset angle, you'd know how high you were pointed.

dish........offset angle
Fortec 80 = 22.75
Fortec 90 = 24.62
Fortec 100=24.62
Fortec 120=24.62

Horizontal is zero. Vertical is 90. You read 25 degrees.
Add 22.75 for the Fortec 80 = 47.75 elevation.

Likewise, if you could get the inclinometer to mount into the front center of the dish, you could take readings there, too.
Or, maybe take a level and lay it across the dish, vertically, then take an inclinometer reading of that.
All of the above suggestions are not very user-friendly.
Not for real-time, anyway.

However , if you could find the offset angle of the arm holding the LNB, then magnetically hang the inclinometer from the arm (close to the dish to avoid distortion), you could read actual elevation in real time.

You'd just have to get one correction factor.
That should be a trivial exercise, and is best left to the user.

I really gotta go try it.

edit: or did everybody know that already??
Did I just rediscover the wheel?

.

**TiminMb** · 09-28-2005 11:03 AM

I asked this because I was so surprised at how vertical my dish is for the highest elevation setting. At 6 degrees of inclination from vertical, I get peak signal on a satellite that should is at 32 degrees elevation. I measured with a inclinometer, not because the number had some meaning, but that it would allow repeatability should I have to change the setup.

**PSB** · 09-28-2005 11:18 AM

Here is an explanation of the angles on an offset satellite dish from a GREAT Scottish satellite web site.............

http://www.satsig.net/22-deg-offset-dish.htm

**Anole** · 09-28-2005 12:58 PM

Originally Posted by TiminMb

I asked this because I was so surprised at how vertical my dish is for the highest elevation setting.
At 6 degrees of inclination from vertical, I get peak signal on a satellite that should is at 32 degrees elevation.
I measured with a inclinometer, not because the number had some meaning, but that it would allow repeatability should I have to change the setup.

You didn't say what dish you had,
...and if I may restate the problem, you meant 6 degrees up from horizontal...

6 + x = 32, so...
32 - 6 = 26
26 degrees offset for your antenna sounds possible.

"up" is 90 degrees elevation, and I was going nuts trying to do the math with 84 or 96 degrees!
Silly me.

edit: after thinking about it some more, I see the error of my ways.
the LNB arm is only useful if the dish has no skew, ie: pointing due south for FTA.
what a shame.