Weird USALS problem

J

jpsr

Regular Member
My Satellite Setup
1.2 channel master, cm polar mount, 12 inch actuator, Andrews feedhorn, Inverto lnb, Superjack positioner, Dreambox dm 500s, Protek 9600ip, 1m channel master with black ultra & 1m gibertini with technomate twin output lnb on astra 1/2, TM 5200 & 1000
My Location
Mullingar, Ireland
After a few problems installing my motorized dish a few weeks ago i got it woking to its best.
I am using a 1m gibertini, technomate 2300 motor, technomate 5200 super+ receiver and andrews feedhorn with inverto lnb.

When i set the motor up using my longtitude of 7.3 w it was perfect getting 98% quality on most sats and 78% on mbc's on 26e for the last few weeks.
The other day i moved to 26e and there was mostly no picture with breakups, all other sats were fine at 98% apart from 1 or 2 that dropped a couple of db, notting major.

I decreased my longitude and at 6.6 and got 26e back to between 74 and 78%.
But can anyone answer why after setting my motor up on my long of 7.3 with 26e @ 78% quality, then a couple of weeks later loose 26e and then have to change long to 6.6 w to get it back.

I just find it weird, can usuals go out of sync.
 
jpsr said:
can usuals go out of sync.
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USALS is just a bit of maths. The receiver works out what angle the dish needs to point to receive from a certain satellite and then sends a DiSEqC 1.2 command up to the motor to move to that angular position. The motor does not send feedback to the receiver so the receiver doesn't have a clue where the dish is really pointing at any particular time.

A motor can get "lost" but if you do a "send to reference" that will sort that out. Other problems could be the dish has slipped around the motor stub or the motor has moved around the mast... Or that it's got a load of backlash.

BTW: you will pick up a load of signal if you ditch the feedhorn and fit a Black Ultra.
 
One answer (from personal experience) is not USALS going "out of sync", but the dish shifting half a degree or so around the pole due to wind, motor backlash etc.

I have two motorised dishes, an 80cm and a 1.1m and the latter often needs a tweak to my USALS Longitude setting. It sure as hell beats going out in the wind and rain to improve mechanical stability!

Edit: Sorry, Huevos, didn't fully read your reply before diving in. But take it as wholehearted agreement :)
 
There was a bit of wind the other night but i did'nt think it would be enough to shift the dish as i made sure the bolts were tight enough.
I had a look at the dish out the window as its a few meters away and the wind was moving the dish a bit.

So is this normal for anyone with a motorized dish to fine tune there dish, does movement effect everyone.
I dont really want to climb the ladder and fix the problem in this weather, I'll leave it as it is.
Maybe i will change the lnb to the black ultra as i heard its good.
 
jpsr said:
So is this normal for anyone with a motorized dish to fine tune there dish, does movement effect everyone.
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They move because of the leverage, not because it is motorised. The dish is 100cm in diameter and it is attached to a 5cm diameter stub. That's a lot of leverage, so it doesn't really matter how tight you do it up if the wind is strong enough it will either move it or brake it.

Try reseting the motor to zero first though as it may be that.
 
I reset my motor to 0 and no difference.
I re alligned the dish to my longitude of 7.3w and i got all sats back perfect and tightend the bolts a bit more, and then there was more wind last night.
So today i had to change mt long to 6.6w again.
There is heavy rain here at the minute so that could be some of the signal loss, but a bit much, would rain fade cause the signal to drop from 98% to 80%.

This is the 3rd time i re alligned the dish, thats including the first installation.
 
Is the house moving :eek:





Sorry :p
 
Sounds like the wind has caused the dish to move a fraction to me. it is probably not as noticable on some of the closer satellites because they have a broader angle at which you can recieve them, whereas something like 26e really needs to be exact so the slight shift has not changed the rest... I had a similar experience recently due to high winds on my brothers system and he kept 19.2, 28.2 and 13e but lost quite a few others.
 
It,s just a bit strange to me that the 3 times i have re-alligned the dish, and this is only in the last 4 weeks, as its when i first installed the dish,
Them 3 times i have had wind shortly after and not vey strong wind either and it seems to have moved the dish.
And each time i have to fine tune the longitude its always 6.6w which i find strange.

Could there be a bit of play in the motor,
 
I'd say that's a definite yes.

A backlash problem with my motor was highlighted when I upgraded to a lightweight 1.2M dish. It will get worse, and having a large Triax acting as a sail may bring it's useful life to an end sooner rather than later. If you want to keep to a diseq motor can I put a word in for the Clarke Tech I now have? It hasn't budged thus far, although the dish is fibre, it's in a sheltered position and we haven't really had high winds since I installed it. Up to now though, I'm very satisfied.

Edit: just noticed you have a Gibertini not a Triax. Same thing applies though. I had a Gibi on the motor before my Laminas.
 
I have heard of backlash, but what is it and how is it caused.
 
jpsr said:
I have heard of backlash, but what is it and how is it caused.
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Basically excessive play in the motor gearing. Usually caused by what I posted in reply #10
 
The technomate 2300 that i have is ment to be anti-backlash, and its only new.

Does this mean my motor is on the way out.
 
I moved the dish side to side and the motor shaft moves a couple of mm each way.

It's not really loose, but enough for the wind to move it.
 
I guess it depends on what that 2mm (or 4mm if the correct setting is at one side of the movement) equates to at the LNB end of the dish arm. Logically it will be more than 2mm. Just another thought, have you tried tightening the bolt and nut that secures the motor stub to the actual motor drive? There could be free play in that.
 
jpsr said:
It's just a bit strange to me that the 3 times i have re-alligned the dish
Click to expand...
Can you give us a quick rundown of your alignment proceedure?
 
It was the bolt that connect the motor shaft, I moved my motor to zero and could see the motor and dish were not lining through, which was because of the free movement of the shaft,moved it slightly, tightened that and re-alligned the dish.

The movement seems to be gone when i move it side to side, and have all sats back sa good as could be got.

The big test is when the wind comes back.
 
That sounds like good progress - the fitting of the stub needs to be done with some care, as you've found. Can be quite tricky to get it all positioned so that the bolt can be inserted and correclty tightened. Let's hope your hardware limits are wide enough, or you'll be demounting the stub again!





Just kidding - the hardware limits are usaually pre-set quite wide.
 
Well, let's hope that solves things. I did have a similar loose bolt when I changed over from a Triax to a Gibertini. However it only affected elevation. They're not the easiest to tighten up I have to admit.
 
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