Problem with STAB HH 120. "3 degree offset ?? "

digib

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22
Hi all,

I have a 110 cm dish mounted on Stab HH 120 rotor. It has worked perfectly for half a year ( it is still quite new ), but recently there was a lot of wind, really extreme in my region and I lost almost all SNR from 100% (100% on 19.2E, about 95% in 13E, 90% on 28.2E, 95% in 30W....) to 65-70 % in 19.2E and almost no signal in the rest of positions.

I thought what happened was that some of the screws and nuts weren't tight enough (what I doubted because I tend to tight them very well) but after lot of test I discovered that all the satelite positions have got about 3 degrees offset to the east, but the Clarke orbital track of my rotor is perfect because if I apply about 30 clicks of steps to the west in the Diseqc 1.2 stored settings for every position (every manual step means 0,1 degree as stated in rotor user manual), I will recover all the lost signal from every East to West position, in my case everything from 28.2E to 30W, which is my full usual testing bench. Obviously USALS is not working anymore with this offset.

I have tried the GO TO 0 option from my enigma2 receiver but nothing seems to reset my rotor.

With this situation, it doesn't seem that anything from the dish arms, brackets or screws have been blended or moved, no problem with orientation nor elevation, clarke orbital is perfect and it seems like if the stab HH 120rotor, being powered off, has been "jumped" 3 degrees to the east but the rotor itself has not "detected" this jump so it will fix the offset doing a GO to 0 reset.

Does anyone know if this behavior of the rotor can be solved, it is really strange :(
 
Last edited:

Robinson74

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558
I'm not sure if I understand you correctly but since you mentioned wind I think your rotor was moved slightly to the east on the pole. This is what happened to my Famaval 110cm some time ago.
See here: https://www.youtube.com/watch?v=1kbw7FJw21c
If so, as a temporary measure you could change your longitude in the positioner USALS menu by 2-3 degrees to the east. So if your real longitude is 10E, change it to 12-13E.
 

digib

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Thanks milan58 and Robinson for replying.

The rotor is correct.The error is in the firmware of your receiver.

But if that was the case, why it is not working well after Go to 0 function (that usually fixed any kind of positioning malfunction) using USALS???

USALS should work perfectly if the rotor is perfectly mounted and the coordinates are well configured in STB, as it seems to be...


I'm not sure if I understand you correctly but since you mentioned wind I think your rotor was moved slightly to the east on the pole. This is what happened to my Famaval 110cm some time ago.
See here: https://www.youtube.com/watch?v=1kbw7FJw21c
If so, as a temporary measure you could change your longitude in the positioner USALS menu by 2-3 degrees to the east. So if your real longitude is 10E, change it to 12-13E.

In your video all I can see is the dish vibrating because of the wind, doesn't seem to have rotated to east or west.

If the rotor had moved on the pole (from the wall mounting) to the east because of the wind, the Clarke orbital would have been modified and the result would be that when moving to a position in the east half, the dish would stop too far east and with less elevation; while moving to the west would result in stoping too early and too much elevation.

But rethinking everything together again, I belive that if the dish has rotated 3 degrees (from the rotor pole) to the east because of the wind, maybe the Clarke orbital is intact but just with this 3 degrees offset to the East. I belive it is either this case or the internal gear of the rotor has jumped 3 degrees to the east while it was power down under extreme wind....


I think I have a protocol to check both cases.

A)If I do a GO TO 0 reset from my STB and check degree indicator in the rotor body, it should stop right in the 0º mark. If it stops in the 3º mark, then the problem is in the internal gearing of the rotor (this would be the worst, because I would end with a faulty rotor very hard to reallign in future)

B)If I do a GO TO 0 reset and rotor stops at 0º, I have to check if dish mounting center mark and brackets are perfectly alligned to rotor pole.

In any case my full set of rotor and dish is mounted in a very hard to work environment, that's why I'm trying to discover as much as I can about the issue before preparing my tools and jump to the roof :mecry:
 
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milan58

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1,646
Not a problem to separate the rotor and see if the gears are a
little worn out!I have the rotor for 10 years and still works well
some gear is a little worn out.Optibox Alligator drives really bad
antenna,DvbDream the computer still runs fine antennae.
I hope you manage to find a solution.Changing the position of 3°
'll lose satellites in orbit Clark's ring.
 

Robinson74

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558
In your video all I can see is the dish vibrating because of the wind, doesn't seem to have rotated to east or west.
Yes, the vibration does not actually show dish rotation but I just wanted to show you how susceptible Famaval 110 is. By the way, what dish do you have?
Anyway, do you use USALS option (longitude, latitude)? If so, I strongly suggest offsetting your longitude and it should show improvement across the whole arc.
At least it helped me a lot some time ago.
 

empb

SU Team: It's All Good (Fausto v1.45/Newcamd/vplug
Staff member
Administrator
Messages
10,231
I'm not sure if I understand you correctly but since you mentioned wind I think your rotor was moved slightly to the east on the pole. This is what happened to my Famaval 110cm some time ago.
See here: https://www.youtube.com/watch?v=1kbw7FJw21c
If so, as a temporary measure you could change your longitude in the positioner USALS menu by 2-3 degrees to the east. So if your real longitude is 10E, change it to 12-13E.

This is what happened to me recently After very high winds (and to dismiss this solution without trying it seems strange to me). Only 1 degree out and after changing Longitude USALs finds almost everthing fine.... (4W & 7.3W being the ones I have to manually adjust most to get a decent lock, but pretty sure I had to do this before anyway and then store the positions under DiSEqC)
 

digib

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Thanks again.

I don't dismiss the "patch" of modifying longitude USALS coordinate trick to keep getting the max signal available, I know that works. But as far as my knowledge and imagination gets, that doesn't represent the real offset I have got because of the winds. If I'm wrong please correct me:

I mean, it is not the same if you live in Finland than if you live in southern Italy, the add or subtract value you may have to apply to the longitude in Finland will be much more lower than if you live in southern Italy because the azimut to correct is bigger in southern Europe.

So in my particular problem, to get again all the signal available I have had to add 1.2 degrees to the East coordinate in the USALS sections.

But the real offset that my rotor/dish equipment has been pushed because of the wind, is 3 degrees, that is the constant that applying to every stored position in diseqC 1.2 mode succesfully allows to get maximum signal.

Well, maybe it is just the opposite theory LOL

In the end until I don't jump to the roof with a 4 meters portable stairs to check everything, I will not know what has really happened. But I wanted to post it here because maybe someone has had some rotor which its gears have been pushed without its position controller being aware of the movement. It seems to be that case because I have good signal in all the clarke orbit positions..
 
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meho7

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314
OP I have the same issue as you do. A few months ago I bought the stab hh 120 after my moteck died. The first thing that was really weird was when i was setting it up the signal of some sat positions was really low - for instance on astra 19.2 I got really low signal no matter what(70% compared to 100% before with the moteck). I tried to realign the dish - changed the elevation did nothing to help. Then I thought it might be a cable issue, faulty LNB or maybe my receiver tuner going to shit. Thankfully i found this post. Could it be a factory defect? Because this shit is driving me crazy
 

digib

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OP I have the same issue as you do. A few months ago I bought the stab hh 120 after my moteck died. The first thing that was really weird was when i was setting it up the signal of some sat positions was really low - for instance on astra 19.2 I got really low signal no matter what(70% compared to 100% before with the moteck). I tried to realign the dish - changed the elevation did nothing to help. Then I thought it might be a cable issue, faulty LNB or maybe my receiver tuner going to shit. Thankfully i found this post. Could it be a factory defect? Because this shit is driving me crazy

Hi, in case you're still interested in this topic, the fault at the time I wrote all this was wind had moved the dish on the rotor pole, so I had that constant offset. I fixed it by readjusting. Nuts were really tight but big dish is not good to heavy winds.

Later on the rotor died. In the end the experience with Stab has not been good, it was supposed to be a good rotor but lasted less than expected. Since then I own a TM2600, more cheap, works equal or best
 
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