Stab HH120 only moved 30* W or E..

[Cham]

I have a Stab HH120 on a 4' Fortec Star dish with SNH-031 Universal LNBF, works great except... Doesn't seem to move more than about 30 degrees east or west (60 degrees total rotation). Is this normal?

Tried to get a couple of the satellites east of AMC-6 and was having no luck. Tried re-aiming, re-tuning, bumping the azmuth back and forth and no signal. Strange since AMC-6 is really strong on this dish. Was trying to get the PBS feeds at 63 deg and maybe some Ku on 58. Then I noticed the dish only moves about 2-4 degrees past 72 when I switch to the 63 deg satellite. If I try 58 deg it just sits there. I can go back to 72 or any satellite west of 72 just fine and try going back to 63 degrees it maybe goes back to 70. It seems like there is an internal limiter or not enough cogs on the sector gear...

It also seems not to move past 127 deg west but have trees in the way and I don't expect much after 125 deg anyway.

Checked the USALS menu in the Pansat 3500 and re-set the unit, no change. Even tried a second receiver (that was used on an SG-2100 that gets 63 and 58 at another location) and no change.

Any ideas?

TNX in advance!

-C.

 

[Lak7]

Possible that Limits are set?

 

[Cham]

Checked that several times... Don't THINK so... unless there is something programmable in the HH-120. I use one Pansat 3500 on my SG-2100 and it gets the eastern sats, tried it on the HH-120 and same result; nothing east of 72.

 

[Sadoun]

Cham

HH120 should move +/- 60 degrees on (East/West).

It is possible, you have the limits set in your receiver. Go to the DiSEqC 1.2 menu and disable limits.

 

[guapoharry]

Can you post a picture of the dish mounting from behind? (where the dish mounts to the motor)

I suspect the dish is imbalanced. It is possible to assemble the parts so that the dish is very top heavy...

 

[Cham]

Sadoun,
Will check again on the disable limits. Tnx for the having the manual on line, it has more info than the one that came with the unit.
Guapoharry,
I can post pictures tomorrow, bit dark tonight. Dish is quite heavy...

Pictures to come soon..

-C.

(edit) Picture is before the rotor was added to the installation, it is pointing at G28.

 

[Cham]

Here are some pictures from the back of the dish showing motor, mast, dish mount, etc.

Mast (motor) mount is set for 49 degrees (my latitude).
Most south satellite is 97 degrees (dish location is 97.1W)
The dish (in the pics below) is pointing at AMC-9 for the RTV mux. Signal (Q) is around 85%

How does it look?

Tnx!
-C.

 

[guapoharry]

It's too dark now to take a picture of my dish, but here's a picture and diagram.

The picture shows a 100 cm dish, This looks like my dish was when first assembling it.

My motor had problems going back to true south from positions toward the east and west limits

Ok, Here's what worked for me. First I flipped beam "A" behind the dish end for end so the long part was on the bottom instead of on the top. The dish would move farther before stalling.

Then, I flipped bracket "B" upside down as well while keeping the long side of "A" down as well. Things improved again. The dish could move even farther before stalling.

It makes sense if you look at the diagram. the red part represents the point where the dish pivots on the motor. The farther the pivot is from the center of mass, the more force it takes to move it back to the vertical position. (bottom row)

The "dishes" on the top row are balanced better...

 

[Cham]

Yes that makes sense... but it looks like my "beam A" is a bit different than the 100cm model in that "bracket B" is centered, there is no longer or shorter side. I could turn "bracket B" over though that might help a bit. I should move "bracket B" farther down toward the motor, that might help to lower the center of gravity a bit more. I have the longer mast on this motor, and I thought when I installed it it might be up too high which causes more moment force on the motor bearings. There seems to be a fair amount of clearance to do this.

This is a roof installation so access is a bit tricky with snow on the roof and all. Supposed to be a really nice day today, might have to do some shoveling and make some changes.

Think I am going to remove the dish and see if the rotation is still limited... would eliminate the "overbalance issue" if it still won't move beyond 30 degrees without the weight of the dish on it.

Thanks for the ideas Guapoharry!

 

[guapoharry]

I stuck a ruler up to the screen and measured between the nut on the top of the adjustment to the nuts on the top of the beam. Then I measured from the nut on the bottom of the adjustment to the nut on the bottom of the beam.

You are correct that the offset is more on the one metre dish than the 1.2 metre dish.

However, my measurement says that the beam on the 1.2 metre dish has an offset, albeit less pronounced...

Good luck.

 

[Sadoun]

On bracket "A", the long side should be towards the bottom. That is the right way of setting up the dish. Bracket "B" is fine.

Also, try using a Horizontal transponder when moving the dish. The receiver will send more power to the motor that way.

Over all, I would recommend using the Sadoun PowerTech DG380 over the HH120. It is a stronger and faster motor.

 

[Cham]

I took off the dish yesterday and tried the motor with no load. Same result. Must be a limit switch shutting off the motor. Had someone switch satellites while I was on the roof watching, and it just gets to the 30 degree mark and stops. No motor effort. Ran out of time so maybe I'll take down the motor and try it inside, maybe disassemble it and see if I can figure it out on the weekend.

On a separate but related issue; the PBS mux at 63 degrees seems weak even on my 10' dish. On my 33" signal is marginal (15-25Q on my Pansat 3500). Is anyone else getting poor signals from this satellite?

Tnx..
-C.

 

[Lone Cloud]

I have a stab120 turning a 1 meter Winegard dish and have had similar problems - in my case mostly its balkiness at moving back to due south zenith.

In looking at my mount setup, I noted that the Winegard mount had an offset on it that looks like it favored a motor where the strut comes out the bottom - like an SG 2100, With the Stab strut coming out the top of the motor, the balancing point of the dish was higher on my setup than where it pivots on the motor, Ideally, I think where the strut angles off is where the weight center of the dish should be.

It looks therefore like you may have the dish attached too high on your strut.

i had to fabricate a steel adapter to get mine closer to the center of gravity. Solved some of the issues, not all.

I also had issues with the VS 9000 receiver I have connected to it. It's just a bad receiver all around.

 

[turbosat]

That satellite at 63 probably should be weak considering where you are. I don't have the footprint map handy, but I have problems getting a good signal on those PBS channels too. Part of my problem is possibly line-of sight obstruction, have a big tree very near that sat's direction.
Lately I've been getting only about 30signal/53 quality or close to that.

 

[Cham]

Well I got it working! Took it down and took it apart... Nice heavy gears etc... Didn't see a problem. Put it back together, put it up, and now it works. Go figure :|
Maybe it just needed to be powered off for a few hours to re-set the memory? Maybe one of the switches was sticking?

The existing lube was clean but I added some new Lubriplate 105 (works excellent in cold weather, I use it for other outdoor gadgets & rotators).

I moved the dish down a bit on the motor mast when I put it back.

Now... As Turbosat indicated, the signal from 63 degrees is rather poor but I get a lock and picture only breaks up once in a while. I might be able to get another dB or two if I replace some old RG6 and eliminate two or three connectors... What we do for fun!!

Thanx to all who responded. Great forum!

-C.

 

[turbosat]

Good work Cham, glad you tickled it into working again!