STAB: Calculating degrees of dish elevation angle?

[Sadoun]

Hi Guys

We just updated the "Motorized dish Elevation Angle" page slightly. I know a lot of you use this page. Here it is: http://www.sadoun.com/Sat/Installati...ion-Angles.htm

:mozilla_cool:

[videobruce]

If there is a elevation adjustment on the antenna, why is there one on the motor?

[Admin]

Of course. That is what that calculator is for.

[videobruce]

??? #-o

[rray32539]

If there is a elevation adjustment on the antenna, why is there one on the motor?

The elevation setting on the motor should equal the latitude of your location. If you are at 30 degrees north latitude, set your motor to 30 degrees.

[ahoss2000]

I think Sadoun web calculations for HH90 is off slightly. According to STA B, the dish angle = Fixed dish angle - (45 - Lat), for 32714 zip, =52-(45-28)=35 . Sadoun web calls for 40.

On my M1 system, 35 worked, 40 does not.

[wejones]

I think Sadoun web calculations for HH90 is off slightly. According to STA B, the dish angle = Fixed dish angle - (45 - Lat), for 32714 zip, =52-(45-28)=35 . Sadoun web calls for 40.

On my M1 system, 35 worked, 40 does not.

For ANY motor, the dish elevation should be set to:

MSOA - declination

where MSOA=motor shaft offset angle. For the HH90, the bend in the motor shaft is 45 deg . Therefore, the dish angle should be :

45- declination.

Now, you have 2 choices for declination some calculators use the declination of your south satellite, which is a poor approximation. For your latitude of 28, your south declination is 4.7 deg, so the dish elevation should be 40.3 . The better choice for declination (assuming that you have added about 0.6 to the latitude setting on your motor latitude scale) would be the declination of a western or eastern sat, which would be about 4.1 deg for your latitude. That would give you a dish elevation of 40.9 deg.
If your system is giving you better results at 35 deg, then something else is wrong with your system, ie either (1) the dish elevation scale is wrong, (2) the lnbf arm is bent, (3) you have the wrong setting on the motor elevation, (4) the dish elevation bracket isn't assembled properly, (5) etc.

[wejones]

..... According to STA B, the dish angle = Fixed dish angle - (45 - Lat), for 32714 zip, =52-(45-28)=35 . Sadoun web calls for 40.
....

BTW, I forgot to comment on your calculation above.
The "Fixed dish angle" specified in the STAB documentation refers to the elevation of a sat to your south. For someone at a 28 deg latitude, this would be 57.3 deg. So your calculation above SHOULD be :

57.3-(45-28)= 57.3-17=40.3

Ie STAB is also using the approximation of using the declination of a southerly sat. I'm not sure where you got the "52" , but you can see that the 57.3 -(-28) is equal to 57.3 + 28= 85.3 ie = 90-declination.
It took me a while to figure out exactly what that crazy equation was doing.

[ahoss2000]

I did not notice that the STAB calculation is for a south sat. I used IA-5 @97 , and the elevation for a fixed dish in my location is 52.

I do not know why my number is off, but I get good signal all the way to Galaxy10R. I do not see a clear marker where I should adjust the dish angle on my Fortec 90CM dish. Right know I read off the number from middle of the LNB arm as seen in the picture:

http://i77.photobucket.com/albums/j6...Picture004.jpg

It would be nice to know where the error is in my system.

Thanks

[Rico.]

The elevation setting on the motor should equal the latitude of your location. If you are at 30 degrees north latitude, set your motor to 30 degrees.

That number and the calculator number do not match ? Can someone please explain.

Thanks,
Rico