Satellite Internet forum

Satellite Internet forum
https://www.satsig.net/cgi-bin/yabb/YaBB.pl VSAT technology and installation >> LinkStar Forum: VSAT hubs and terminals >> Linkstar pointing tool https://www.satsig.net/cgi-bin/yabb/YaBB.pl?num=1231759143 Message started by satnew on Jan 12^th, 2009 at 11:19am

Title: Linkstar pointing tool
Post by satnew on Jan 12^th, 2009 at 11:19am

Anyone have idea what's the use and how to use pointing tool in Linkstar modems?
Please help.

Thank you

Title: Re: Linkstar pointing tool
Post by Eric Johnston on Jan 12^th, 2009 at 12:00pm

Use command tcmp

Note the QPSK BER figure. This the the bit error rate on your received outlink carrier, prior to FEC being applied.

QPSKBER= 0.1 �is very bad
QPSKBER= 0.00001 is good

There is no 'good enough' value after which you can stop working; what is important is that you get the antenna peaked to centre minimum value. � Adjust pointing to the minimum.

You will need to type tcmp perhaps 50 - 100 times. So the command rep tcmp may be useful; it re-displays the information every 5 seconds. �Average several readings to improve the accuracy.

Best regards, Eric

Title: Re: Linkstar pointing tool
Post by satnew on Jan 12^th, 2009 at 12:10pm

Copy that.

Thank u very much Eric.

Title: Re: Linkstar pointing tool
Post by anietiejohnjames on Jan 28^th, 2009 at 6:04pm

Thanks Eric. I needed this for a long time now.

Title: Re: Linkstar pointing tool
Post by satguru2k2 on Jan 31^st, 2010 at 6:51pm

eric, thanks a million for this i love u !but-just 2 push my luck, can we make it any faster than every five seconds .i.e can we actually use it to point a signal?

Title: Re: Linkstar pointing tool
Post by Eric Johnston on Feb 1^st, 2010 at 11:54am

I don't know if it is possible to speed it up. If you did shorten the time, the readings would vary more from one to the next. I suggest you wait 20 seconds and average the four readings in your head to get some accurate idea of the bit error rate.

When peaking up, I mispoint the dish slightly till I get a distinct lower reading and note this reading accurately. �Then I move the dish, counting the turns and flats on the nut, till I get exactly the same low reading on the other side. �Then move the dish back to the exact centre by halfing the turns and flats.

This method works perfectly in elevation as there is no backlash. �In azimuth it is necessary to always approach from the same direction. �Marking one flat on the nut with black felt tip pen helps with the counting.

Best regards, Eric.