SatSig topic:

Linkstar pointing tool

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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

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

Jan 12^th, 2009 at 12:10pm

Copy that.

Thank u very much Eric.

Jan 28^th, 2009 at 6:04pm

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

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?

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.