Close but no cigar ..extreme East still eludes me

[Vipersan]

Hi friends ...I've been up and down my ladder till the arches of my feet ache ...
..but Im still having probs at the extreme East of the arc..
As mentioned in a previous post
Im using the following :-
SG2100 not the (a) version

Triax 110 offset dish.

My location is Lat 53.5N Long & -2.35W

I've set the Elevation and declination for max signal at the top of the arc ..peaked using a meter at 1W

and much tweaking later I have the dish getting 70% signal from Intelsat 707 (53degW)
and all sats and channels to 1W including a watchable stable picture early evening ..vertical transponders only ...from that elusive Nilesat 7W (Dubai 1).
Sweeping Eastward ...all signals are excellent to about 19E ...but degrade a little down toward Astra 28 deg ~(60% signal).
On a 1.1mtre dish this sat should be pumping nearly 100% ...
From here on East the signal degrades further until the last sat I can receive is Eutelsat W4 (36deg E)
Signal strength is now down around 25% and breaks up in the late evening.

Beyond this point I cannot get a lock on Hellas 39 deg or Turksat 42 deg..
I have no obstructions to reception until about 56East ...and I did used to be able to reach these 'birds' before the winds last year ..

So I have near prefect tracking of the western arc
The dish was peaked at 1West
Usable signals for most of the Eastern arc ...and a very rapid drop off around 36degrees and onwards..

I plan to give this another go to try and get it perfect ...but would be better armed if one of you experts could work out from my lengthy description where the error lies ..
Elevation /Declination / dish rotation around the motor mount ...true south misaligned ..etc ..
The amount of error must be less than a degree ..but its sure frustrating...and acuracy is all the more critical because it a fairly large dish.

..if you stuck with me this far ..I salute you
rgds 2 all
VS

 

[satelliteman]

Check the following: pole is dead plumb, motor inclination is correct and dish is centre on motor shaft.

Did you motorise the dish to 1W prior to alignment?

 

[Robbo]

I think that you have more than one thing wrong with the setup, and the effects you see could be caused by a variety of factors.

So, you need to check that you have the basics right,

Like getting the pole spot on vertical, and making sure that the dish is on the centre line of the motor shaft.

 

[Vipersan]

@satelliteman & Robbo....
My intial setup involved making sure thhe motor pointer read zero ...and the dish was at right angles to the zero position ....
I then rotated the motor and dish combined to true south as indicated by dishpointer dot com ....I further checked true south using calculation tables for the suns zenith ..and the shadow cast on that day at 1:12 pm ...
It was bang on ...
I then entered my long.lat into the receiver and drove the dish to 1W ...where I then used a meter to monitor signal strength and fine tuned Elevation ..previously coarse set with the motor scale ...and dish declination for max strength

ref ..to pole ...
I have checked with a magnetic inclinometer (within 0.5 deg of vertical all round )...and futher checked with a small spirit level ...
..looks good to my old eyes ..

I can't use diseqc to move the motor to 1W as my receiver only supports usals..

There is one further complication in that my motors 'zero' apparently isn't fixed ...
..the old SG2100s can have the zero position moved or possibly corrupted ...and has to be reset by moving the motors pointer/scale to zero ..and then use a pin to push a hidden reset button.

I did have to do this once after a power failure whilst the motor was being driven..

rgds
VS

 

[wod]

as your using usals positioning you just need to move the dish to 1west and move it around the pole to align up on 1west, no need to have the motor on zero degrees

then drive the dish to 42e and 30west etc to check the dish elevation and you should be good to go

 

[Vipersan]

Thanks for your input Wod...
Im sure I've already tried that ...but I'll give it another go ...
I assume the long lat offset is entered into the receiver before driving to 1West ...and the rotating the whole assembly around the pole.
rgds

 

[Robbo]

Thanks for your input Wod...
Im sure I've already tried that ...but I'll give it another go ...
I assume the long lat offset is entered into the receiver before driving to 1West ...and the rotating the whole assembly around the pole.
rgds

Yes, that is correct.

Also if you look on the motor shaft there will be a vertical seam down the front, this should be right in the centre of the dish bracket, guessing that having the dish at 90 degrees with the motor on zero would get this, but worth double checking anyway.

 

[Vipersan]

Thanks Robbo...
Yep ..I spotted the seam down the shaft ..
I lined it up with the hole in the back of the dish bracket ...but of course this may not be acurate if the bolts were to be tightened unevenly..
I made sure to apply the same number of turns to each nut in turn so the action of tightening didn't rotate the dish..
Problem is its in place and viewing the clamp/hole/seam from the front isn't practical.
I'm confident I have this correct within reason...short of taking the whole assembly down to check..
I don't fancy that as its so heavy..

Given some fine weather ...I'll give the alignment another go..
Cheers for all your help
VS
;)

 

[Lazarus]

Even if you are sure the Dish is correctly positioned on the Stub, do recheck as you tighten off the clamps.

When I first stuck my TD110 on a motor, I also had an inexplicable tracking error - made all the more curious 'cos the rest of the installation had previously been used with another Dish with no problems.

After a while, I discovered that upon tightening the clamps (which had those little right angled cutouts on the bitey bits) that the Dish had slipped very slightly out of true and was being gripped assymetrically, despite me being convinced I'd tightened them equally. The weight of the Dish certainly the crucial factor and will remain a potential problem for installers until the human race grows a third hand.

Loosened, re-tightened with care and two minutes later tracking was perfect.

Edit: Just to clarify, the slippage was not so much rotation around the stub, but effectively a slight twist (or skew, to coin a phrase) ie Motor Stub Datum mark vertical but Dish a tiny bit out of vertical alignment with the mark.

 

[Vipersan]

Thanks for your reply Tivù ...most interesting ..
I hadn't considered the dish might be vertcally out of line with the motors stub mount..
In fact I hadn't even thought it possible ... as the 'right angled bitey bits all make contact with the stub what looks to be evenly.
Now I'll have to count teeth to make sure is the same tooth both sides and on both clamps..
..couldn't lend me that third hand could you ;)..
Can I also ask ..since you have the same dish ..
Did you notice how accurate the declination scale was ..
My calculations for my location say it should be approx 23 deg..
..when in fact I don't get signal until its set around 25 >26..
another triax quirk ?
cheers m8
VS

 

[satelliteman]

Yes, start with the motor on zero, enter your location details and motorise the dish to 1W; motor will move to the calculated position based on your details. Then align up the dish for reception of this satellite by adjustment of the motor/dish together around the pole and declination using the dish elevation adjustment.

If you send the dish to the far East where you have no signal, spring the dish in all directions and see if the signal improves. This will tell you where the problem is.

Elevation scales are not accurate enough to use for declination settings when setting up a motor installation.

 

[Lazarus]

Did you notice how accurate the declination scale was ..
My calculations for my location say it should be approx 23 deg..
..when in fact I don't get signal until its set around 25 >26..
another triax quirk ?
cheers m8
VS

Elevation scales are not accurate enough to use for declination settings when setting up a motor installation.

Yup. What da man said.

Sorry for not replying sooner - been picking Gooseberries. Blood everywhere. Now can I have my third hand back?

 

[Vipersan]

Yup. What da man said.

Sorry for not replying sooner - been picking Gooseberries. Blood everywhere. Now can I have my third hand back?

Sorry m8 ...my need is the greater...
You can have it back when I can see everything from 42E to 53 W..

cheers

 

[cocker80]

I did not use the elevation scale on my dish because it is totally cocked up. I set my dish use using 12169v 28000 on 1w (CityTV), for me it is a weak transponder but between 7.00am – 9.00am I usually get a good signal. I tweaked the dish position and elevation to match that transponder and I would say it spot on the acre now.

I did experience the same problem as Tivù, when tightening the bolts on the dish clamps it through the dish ever so slightly out of position so watch out for that.

 

[satelliteman]

Self tap screw threw the El bracket before tightening up the bolts. Nice little tip that Robbo had mentioned previously

 

[cocker80]

I’ll give that a go Satelliteman. Every now and again I have to re-align, I can only assume that the weight of the dish is moving it slightly on the motor.