Motorised Installation: Is My Satellite Installer Correct About A Vertical Pole?

[rpm123]

To give some background, I have a 1.1m motorised Triax dish at my old house on which I receive a pretty good signal across the arc despite the fact that my dish was on a pole attached to my chimney. I use the dish quite a lot for feedhunting, and the signal strength for feeds is generally lower than for channels on the same satellite, so getting the setup right is crucial.

At my new place (again in London, just 4 miles away from my old) I am in the process of installing a 1.1m motorised dish, this time mounted on a pole attached to the wall up on the roof (it's a terraced house)

Nearly all of the setup guides I have read have stressed the importance of an exactly vertical pole. However, some mention a vertical bracket.

Today we struggled to get a good signal consistently across the arc. Astra 28 and Arabsat 26 were stronger than at my old place, but then we lost Hispasat 30. When Hispasat was adjusted to give a strong signal, we lost signal east. Meanwhile, for most of the satellites in the middle, including important feed satellites such as 1W, 12.5W, 7E, 10E, the signal was worse than my old place (I measured signal on most of the satellites with the same receiver, with similar weather conditions at time of measurement).

I pointed out to the installer that the pole wasn't vertical. He told me that it's not the pole that has to be vertical, but the bracket holding the dish. Also, he said the leveller to measure the uprightness of the pole should be used in the middle of the pole , and we couldn't measure this because of the dish and the cables being there. He said you don't measure the straightness of the pole at the top. But I thought surely if the pole is straight at the top, it is also straight in the middle, unless the pole itself is bent?

Furthermore, he said another reason I might get weaker signal in my new place compared with old is because of possible interference from police transmitters, wifi, mobile phone networks and so on (there are no trees or physical obstructions). He also said the night-time and daytime signals vary a lot and the signals can be much stronger at night.

So my questions:

(1) Is he right about the pole? Does the pole HAVE TO BE 100% straight or is it the bracket & clamp that really matter
(2) Is he right about the effects of possible signal interference from other sources and also significant difference at day and night.

I've known him a few years, and he did spend a lot of time adjusting.

To give you an idea, in my old place I get 86% signal on RTVGE on 7E which is enough to give me a decent signal on 7E feeds, but at my new place only 69-75% which isn't. When the dish was adjusted to give 75-80% on 7E, we lost signal on other satellites.

Any advice would be appreciated

 

[rolfw]

Pole should be plumb where the dish motor is mounted onto it.

There's always a possibility of interference, is this the same dish and LNB you had on the last property?

 

[rpm123]

Pole should be plumb where the dish motor is mounted onto it.

There's always a possibility of interference, is this the same dish and LNB you had on the last property?

OK, but if it is plumb where the dish is mounted, surely it should also be plumb along the entire length of the pole?

It is not the same dish as previous house (that one is still there), but same size and manufacturer (1.1 Triax). The LNB is not the same, in fact it's a higher quality LNB at the new place. We tried changing the LNB but there was no gain. The other difference is the new installation is with a Diseqc motor. (The old one has a 36v motor controlled by a Manhattan receiver with 36v positioner). Actually the old style motor I found much easier than the Diseqc, with the latter being very hard to fine tune when moving between satellites.

I can confirm that high quality WF100 cable has been used, and the length of the cable run is not signifcant.

Just can't work out why my signal is worse than the old place. I would have though I could get a much better signal than I got with the dish on my chimney. Something doesn't strike me as right about the top of the pole not being plumb vertical (and couldn't measure the middle because of the dish/cables), but when I pointed this out the installer was offended at me telling him how to do his job :-(

 

[Huevos]

1) For me your question doesn't make a lot of sense. How is it possible to get the bracket straight if the pole is not straight? Like Rolf says the pole needs to be plumb. East/west is the most important as there is no way to adjust out any error. Once the motor is facing due south just rest a spirit level east/west across the bracket and this will confirm if the pole is vertical.
2) Local interference normally shows as a spike on the spectrum and will only affect a handful of transponders that have a similar IF, not a whole satellite.

BTW, if you are nailing the satellites on one side of the arc but not the other that means the width of the arc is not correct. Also even if the width of the arc is wrong the central satellite should still be perfect as this is the first to be adjusted.

 

[Captain Jack]

I always make sure that the pole is 100% vertical. I have never measured the bracket itself (I am assuming you are talking about the sides of the motor housing?). But yes, the pole has to be 100% vertical - if it's vertical everywhere, the chances are that the rest of the system will be vertical too. Is it vertical? Put the spirit level on 4 sides of the pole to check this.

The width of the arc is governed by the motor's elevation settings and the dish's inclination. How was the dish/motor transported? If the dish and the motor were not separated then the adjustments to inclination should be minimal.

 

[rpm123]

1) For me your question doesn't make a lot of sense. How is it possible to get the bracket straight if the pole is not straight? Like Rolf says the pole needs to be plumb. East/west is the most important as there is no way to adjust out any error. Once the motor is facing due south just rest a spirit level east/west across the bracket and this will confirm if the pole is vertical.
2) Local interference normally shows as a spike on the spectrum and will only affect a handful of transponders that have a similar IF, not a whole satellite.

BTW, if you are nailing the satellites on one side of the arc but not the other that means the width of the arc is not correct. Also even if the width of the arc is wrong the central satellite should still be perfect as this is the first to be adjusted.

The pole is visually (to the naked eye) slanting \ - in this case West to East (only slightly but clearly noticeable), and the spirit level confirmed this.

I always make sure that the pole is 100% vertical. I have never measured the bracket itself (I am assuming you are talking about the sides of the motor housing?). But yes, the pole has to be 100% vertical - if it's vertical everywhere, the chances are that the rest of the system will be vertical too. Is it vertical? Put the spirit level on 4 sides of the pole to check this.

The width of the arc is governed by the motor's elevation settings and the dish's inclination. How was the dish/motor transported? If the dish and the motor were not separated then the adjustments to inclination should be minimal.

Yes I meant the sides of the motor housing which is attached to the pole

. Funnily enough at the moment, I have a very good signal on Hispasat, and pretty decent on Badr 26E, but down the middle pretty much from 10E to 15W it's significantly less than I was getting before.

The dish and motor were packaged separately.

I think you guys are confirming what I thought, but he was insistent that his way was the right way and that I shouldn't tell him how to do his job.

How would it be possible, in terms of the arc, for me to be on the arc at 26E and 30W but not down the middle?

 

[Channel Hopper]

The pole is visually (to the naked eye) slanting \ - in this case West to East (only slightly but clearly noticeable), and the spirit level confirmed this.




. Funnily enough at the moment, I have a very good signal on Hispasat, and pretty decent on Badr 26E, but down the middle pretty much from 10E to 15W it's significantly less than I was getting before.


I think you guys are confirming what I thought, but he was insistent that his way was the right way and that I shouldn't tell him how to do his job.

How would it be possible, in terms of the arc, for me to be on the arc at 26E and 30W but not down the middle?

I think the change in the 'verticalness' of the pole has led to a difference in the elevation of the motor bracket, and your installer may have adjusted the elevation of the dish to compensate, which actually alters the declination, and therefore the arc tracking. You really should get him back. Is the dish in a difficult location to set up (at the end of a long ladder )?

 

[rpm123]

Well I'm actually having 2 motorised dishes installed at the new place- he came back to do a channel master 1.2 today - and will have another look at redoing the 1.1 tomorrow. The dishes are pretty easy to access to be honest. Much better performance on the 1.2, though 1 or 2 problem satellites which I am creating another thread about.

 

[rpm123]

Some pictures of the new 1.1m motorised setup. I hope these illustrate what I meant about the pole being straight versus the motor:

 

[rpm123]

and more pictures:

 

[sonnetpete]

Well......in the first photo with the spirit level, I'd say the pole was quite a way off vertical.....the motor housing may be very slightly off.....the pole being inclined like that would lead your motor arc to be tracking a bit off the actual satellite arc I think, probably slightly over the top of it.....someone else will confirm if I'm right....

 

[Lazarus]

Has the correct Scale (Motor bracket has "Elevation" on one side and "Latitude" on the other) been used? The Elevation Scale should be ignored and only the Latitude Scale used.

And

Even if the correct Scale has been used, has the Datum mark been correctly identified?



To be specific, the correct scale to use is the one illustrated by the pics and it should be set to 51.5 (ish)

It looks suspiciously to me as if it's set to the wrong figure.



If I'm right, then setting the motor bracket correctly will mean that the dish elevation bracket will need adjusting to bring the dish back to the correct actual elevation again.

 

[rpm123]

I have attached the elevation and latitude settings below ...

 

[Lazarus]

I'm only interested in the Latitude Scale, and it is set to 55, which is 3 or 4 degrees too high for London.

The Elevation Scale shows the same 4 degree error, as it must. Should show 39.

So ............... raise the Motor so it's set to 51 vs. Latitude (or 39 vs. Elevation)

Then lower the dish elevation bracket by three or four degrees to compensate.

That should improve your tracking.

 

[Channel Hopper]

It is almost impossible to get the DiSEqC motor clamps to 'bite' on a pole like that. If you can get a short length of scaffold pole to replace it with you will have a much better chance of the system staying where it is once you have tightened everything up.

 

[rpm123]

So I should be looking at the tiny straight line after the circle, rather than the edge of the circle, when setting latitude?

In terms of the pole, what is the best diameter pole to use?

 

[Lazarus]

So I should be looking at the tiny straight line after the circle, rather than the edge of the circle, when setting latitude?

Yes - it should be reasonably easily discernible. Certainly in your pics the datum on your Elevation scale is very clear, so although I generally advise people to ignore it, it might be more expedient to use it on this occasion and to set it to 39.

Then drop the dish elevation 3 or 4 degrees to compensate.

 

[Channel Hopper]

So I should be looking at the tiny straight line after the circle, rather than the edge of the circle, when setting latitude?

In terms of the pole, what is the best diameter pole to use?

3 inch is ideal, but in your case stick with 2" as you can keep the existing u-bolts on the T/K brackets

 

[Captain Jack]

I still don't understand why the pole is so far off vertical though....

 

[rpm123]

we are going to redo the pole.

Just to confirm, in terms of setting the latitude/elevation, should I be using the green or yellow circles I have drawn in my picture below?