how I set my dish up (long)

[pete_l]

This is a howto on the method I used to align my dish.

I knew I wanted to point at Hispasat (30W), so I used one of the satellite alignment sites
to calculate the azimuth (left/right) and elevation from my location. This returned values of
Elevation=25 and Azimuth=219 (magnetic) degrees. It also told me that I should turn the
LNB 20 degrees anticlockwise (facing the dish, with my back to the satellite).

First of all, I tried using my compass to find 219 degrees. This failed as whenever I moved
the compass near the dish, to align it, the compass needle was deflected by all the metal
n the dish, arm, LNB and cable. This threw me off by over 10 degrees - but never by the
same amount twice, so I looked for another method.

Now, I knew from using the compass away from metallic objects that there was a tree a
few hundred metres away that was pretty much due south. So I painted a small dot on the
top of the dish and another on the top of the LNB and "eyeballed" the alignment to due
south - then a smidgeon to the west, hoping to find the satellite at 1W. This satellite
needs an elevation of 28 degrees.

I also loosened up the elevation clamp on the dish, to make it easier to swing it up and
down. Fortunately there wasn't much wind, but this introduced another problem: see later.

The next thing was to make an inclinometer to get the correct 28 degrees of elevation.
A short google for "protractor" and "template" gave me what I needed. I printed it out
at full A4 size, stuck a pin through the zero-point with a thread weighted down with
a hex-nut - viola!

My dish is a Triax TD88, with an offset LNB arm. The nature of this dish is that the arm
offset adds 22 degrees to the elevation of the dish. So for my case, to get a 28 degree
elevation for Thor2/3, I needed the outer rim of the dish to be at 28 - 22 = 6 degrees
up from vertical.

Since I am using a Skystar2 card in my PC, it was impractical to try for alignment by
viewing the received picture. Plus, the nature of the software I was using meant that until
you scan a satellite, you can't select a station to view - a nice little catch-22. Also, the
daylight was far too bright to be able to see a screen, anyway.

I had previously bought a little sat-finder from Maplin. This is battery operated and has
a meter which shows the signal strength from a satellite. it also has a sensitivity control
so you can back-off the meter reading once you get a satellite, to tweak your alignment
for best signal. This was connected up and I set the sensitivity so that the needle was
reading about halfway on the meter, with no satellite in sight.

My alignment method was to swing the dish left and right slowly until I got a "kick" on the
meter. Once I got this, I'd slowly move the dish back to peak the signal. Once the left/right
position was at its peak, I made small up/down adjustments to get the best signal. Strangely
the optimum elevation wasn't quite where it should've been.
Back indoors and scan the satellite: no channels found. I tried another satellite and found I
had gone too far - I was actually pointing at Nilesat/Eutelsat at 7 or 8 west (I was getting
channels from both satellites)

Now, here's my trick. Once I had identified one satellite, I taped a thread onto the top of
the LNB and weighted it with another nut. I adjusted the length of the thread so the nut was
just off the ground. The point where the nut hung was marked "7W" with a small piece of
tape stuck to the patio.

Back I went to find Thor at 1W. This time I got it. Now with 2 known points on the ground,
I was able to draw an arc centred on my pole and from this, calculate where I needed to
point to get 30W. This got me a strong signal on my meter, but didn't show up any digital
stations (anyone know what I hit?). I tried a little further around the arc, with my dish now
reset to a 3 degree inclinination from vertical. Got it! Mark that point on the ground, too.

The final part of the story was making my loose and adjustable setup into something more
stable. By having the hanging nut just off the ground, and it's position marked, I was able
to reset the dish position quite easily. I found that as I tightened up the nuts holding the
dish to the mount, the position of the dish would change: in both az. and el. I got the
azimuth tightened and pointed through successively tightening/readjusting the position
relative to the marked point on the ground.
For the elevation, I found that as I tightened the nuts at the back of the dish, it moved
up in elevation. So by tightening the elevation nuts and then moving the dish "lower" I
was able to keep the dangling nut at the correct height without having to continuously
go back indoors to check the signal quality.

Oh yes. The LNB polarisation. All this was done with the LNB "horizontal". When all was
said and done, I twisted it by the required 20 degrees and found that it made almost
no difference: the signal quality on the station I was monitoring went from 85% to 87%.

[BGonaSTICK]

Hi Pete.

Very ingenious. Whatever works for you!

In reality, what you describe is what we all have to do by whatever method we find comfortable. The alternating elevation and then azimuth adjustments is good, and also finding some sort of real-world reference to hang your hat on is very necessary. Tightening of the clamp bolts will always throw you out a bit, and it's worth re-visiting your settings to take account of that, as you've done.

I like your transcribing of an arc on the ground Very good. Once you've got your curve, at least you can get a pretty good idea of where everything in between two known points should be

Your logical approach and preparation has clearly paid off. Use all the theoretical tools and calculators to put you in the ball-park, and then make small adjustments (using a meter, if possible) to align theory and reality. The two are never a perfect match in my experience.

You'll probably find that after you've done it a few dozen times, you'll know instinctively where all the satellites are. That's when you know you've been in the garden too long

Thanks for sharing your experiences!

You can carry this game a lot further with a DiSEqC motor. Using the Skystar2 and the MiBi motor plugin you can spend ages fine-tuning your azimuth for each satellite in the software. The plugin really is superb and gives you more flexibility than any other positioning software I know.

STICK

[anthony coote]

I like your ideas on finding the satellites. I have a Fortec Star Lifetime II receiver coupled to a Stab 90 motor. I must be thick or missing something. I went into the menu on the receiver, picked USUALS & found Hotbird, then I went into the menu again, picked USUALS & found Eurobird. Now my question is this, how do I move from 1 satellite to another withour having to go into the menu system everytime. I must be missing something, somewhere. Also where on the dish do you measure your elevation from. Hope somebody can please be of help.

Regards to all on the forum, Anthony Coote

[robbo71]

Originally Posted by anthony coote

I like your ideas on finding the satellites. I have a Fortec Star Lifetime II receiver coupled to a Stab 90 motor. I must be thick or missing something. I went into the menu on the receiver, picked USUALS & found Hotbird, then I went into the menu again, picked USUALS & found Eurobird. Now my question is this, how do I move from 1 satellite to another withour having to go into the menu system everytime. I must be missing something, somewhere. Also where on the dish do you measure your elevation from. Hope somebody can please be of help.

Regards to all on the forum, Anthony Coote

It depends on what receiver it is. On mine for example there are two ways:-

Press the sat button and choose a different satellite.
or
If the channel list is currently showing all satellites, pick a channel that is on another satellite.

For a motorised dish the overall elevation is set in two places:- On the motor body, which is set to your latitude. On the dish back there should be a scale, you can set this according to the manual, or alternatively adjust the dish elevation (declination) for max signal or your nearest to due south satellite.

Robbo