Home page of Satellite Internet and Information

Satellite Internet Forum.

Welcome, Guest.
Welcome to this satellite broadband discussion forum. Wherever you are and whatever your problem we are here to help each other. Connecting to the internet via satellite is not always easy but is critically important to those in remote places or with poor terrestrial infrastructure. Both service providers and customers are encouraged to contribute. Register at the bottom of the forum home page if you wish to contribute or ask question. Read the Forum rules.
      Satellite Internet Forum : Home Page          
Pages: 1

AMC 12 installation in East Africa

(Read 2926 times)
Ex Member
Ex Member


Mar 1st, 2007 at 11:57am  
Dear all, am installing a 2.4 m dish in mombassa ( Kenya)and will be pointing to AMC 12. after calculating my Azimuth and and Elevation, i realized my Elevation is very very low. i had -18 deg after subtracting the offset. Can any body advice...
Back to top
 
 
IP Logged
 
Eric Johnston
Senior Member
***
Offline


Personal text from Profile,
Options, Top line

Posts: 2109
Reply #1 - Mar 1st, 2007 at 4:51pm  
If you try very low elevation angles you may find the bottom back edge of the dish hits the mounting post.

You can solve this by turning the entire dish upside down.  The feed arm will be at the top and the feed high up, looking down, so you will need a ladder to access the BUC/LNA/feed.  Take great care.

Think:  When the front face of the dish is vertical the beam elevation angle is either the offset angle (in the normal case) or the beam elavation angle is minus the offset angle and down into the ground (in the dish upside down case).  In the upside down case, tilt the dish backwards by the offset angle and the beam elevation will then be zero, i.e. towards the horizon.  Then tilt it back a further 5 deg, for example, to set the beam elevation to a wanted 5 deg.

Best regards, Eric.
Back to top
 
 
IP Logged
 
Ex Member
Ex Member


Reply #2 - Mar 3rd, 2007 at 3:53pm  
Thanks!!!
Back to top
 
 
IP Logged
 
Eric Johnston
Senior Member
***
Offline


Personal text from Profile,
Options, Top line

Posts: 2109
Reply #3 - Mar 3rd, 2007 at 5:20pm  
Here is a picture illustrating the above.
...
Note that operation below 10 deg elevation angle is not advised for Ku band operation or below 5 deg for C band operation.  The path length through rain is long and you suffer more rain attenuation and noise increase, also you observe tropospheric scintillation where the signal goes up and down all the time like the twinkling of a star near the horizon.

Best regard, Eric.
Back to top
« Last Edit: Mar 5th, 2007 at 5:08pm by Eric Johnston »  
 
IP Logged
 
Pages: 1