OTHER HH90 out of range

[swyman18]

Hi all,

I just purchased an HH90 to motorize my 90cm dish here in Hawaii. I've done a ton of reading to prepare for this, but I suspect my location is causing a problem. Initially I connected my receiver to the motor and wanted to check the operation to make sure it would be able to move to all the Ku sats I wanted.

My latitutude = 20.08N
My longitude = 155.46W

I entered my lat/long into USALS section and started with my closest sat to true south that I can receive which is 125w. I confirmed the motor moved about 30 degrees to the west.
I proceeded to each sat down the line (121w, 105w, 103w, 99w) and the motor moved as expected. However, when I got to 99w I noticed the pointer on the motor was already at about 65 degrees. Sure enough, when I went to turn on USALS for 97w, I got an "Out of Range" error.

I made sure there were no limits set in the receiver, so it appears it knows that the motor can't continue past 65 degress or so on the motor scale.

So, does this mean I'm out of luck and the motor won't be able to move to anything past 99w?
Or is it possible to point the motor somewhere closer west rather than my true south and trick it to have that be my 0 degree reference point? I'm thinking probably not.

Or, does a motor exist that will allow me to get closer to the horizon from my 155.46W latitude?

Thank you.

 

[a33]

so it appears it knows that the motor can't continue past 65 degress or so on the motor scale

As far as I have read, (some) receivers refuse to do USALS-calculations at extremes over about 60 degrees from center.

So you can try to move further east/west with the commands MoveEast/MoveWest, or how they are called in your receiver.
When you find a more extreme sat, you can store it with diseqc 1.2 (outside of the USALS-part ofyour receiver).

Moving further east/west, you can see where the motor hard limits are set. (Did you already do an Erase Limits command, for the soft limits?)

Edit: BTW. I've no experience with the STAB HH90 myself; only with the HH100.)

Greetz,
A33

 

[swyman18]

Ok thanks... using DiSEqC 1.2, am able to squeeze a few more degrees, but it won’t go past 65 degrees on the motor scale. The HH90 manual says the physical limit is 72 degrees, but I guess my receiver won’t allow it. I’m using a cheapo GTMedia v7s for now.

The Erase Limits command you speak of, is that something that would be issued from eve receiver? I made sure all the limits are disabled, but I don’t see a command to erase all limits.

 

[a33]

Ah! Yes, 'disable limits' is the right command.
Sorry, the (soft) limits are not erased; I used the wrong word.

When you use the MoveEast and MoveWest commands, the only thing that can stop the movement are the hard limit switches, as far as I know.
I don't know if other motors have a wider range, or if you can (easily) change the position of the limit switches in a HH90.


For a sat like 95W (as per your earlier thread), you need to have 68 degrees motor angle, I see from my calculator.

Temporary workaround: As the (modified) declination offset angle for your site is just 3.0 degrees (with modified motor elevation angle of 69.5), maybe you could set the zero-position wrong; that would help, and probably be workable (but I only suggest this, because your declination angle is so small). And that only works, when you don't want to receive satellites at the other extreme.

So, not an easy situation....

Greetz,
A33

 

[swyman18]

Thanks, appreciate it. I may dabble with the temp workaround to try it out.

So, with the motor normally pointed to true south, these are the settings I have per DishPointer.com with HH90 selected:

Motor latitude = 20.1
Dish elevation = 42 degrees

If I wanted to set my 0 reference to 125w, what would I set my dish elevation to? Would I keep motor latitude the same?
And I assume lnb skew can’t stay at 0?

Thanks!

 

[Need2learn]

Ok do this forget the latitude and just put in longitude = 155.46W next with the motor is on zero, turn the dish and whole mask due south and add your magnetic verification that will get your TRUE SOUTH. Next go to your receiver in your house and set your dish limits east and west, next set your receiver to AMC 21 which is 125 west once you find that peak your dish. Make sure your elevation and declination on your dish is correct.

 

[swyman18]

Ok do this forget the latitude and just put in longitude = 155.46W next with the motor is on zero, turn the dish and whole mask due south and add your magnetic verification that will get your TRUE SOUTH. Next go to your receiver in your house and set your dish limits east and west, next set your receiver to AMC 21 which is 125 west once you find that peak your dish. Make sure your elevation and declination on your dish is correct.

Ok, but isn’t what you just described the “normal” motor setup where motor zero is my true south? When I set it up like that, anything lower than 99 west is out of range even with no limits defined.

 

[a33]

So, this is a bit terra incognita for me, so I'll think out loud about how to set this up. (No guarantee that I don't make a thinking mistake.)

First, I assume you only want satellites east of you, and no satellites west of you?
In that case I would set the motor at due south, but the dish already aiming east on the motor shaft.
That way the motor axis rotates still at the proper angle, and I think the dish also follows the eastern part of the arc as it should.

Use the modified motor elevation angle for you site, as I wrote: "(with modified motor elevation angle of 69.5)".
That would mean motor latitude (90 - 69.5) = 20.5 degrees.
Motor on the pole, aiming exactly south.

To reach the horizon, 75W, you'd have to have a motor rotation angle of 89 degrees, so about 25 degrees further than your motor limit of 65 degrees.
So we can indeed try to setup 125 W as your "zero" satellite (30 degrees difference).
Note: with the dish mounted non-central at the motor shaft, it might be that at the east extreme, the dish structure collides with the motor mount! So test how far you can go, without colliding, before you test the extremes.

Dish elevation angle for 125W with motor axis due south: I'm sure it can be calculated, but I'm not sure how, at this moment. So I suggest trial and error.
Needed/calculated elevation of the satellite would be 48.3 degrees.
One hint: due to the fact that the LNB is not at the exact bottom of the dish, the offset angle effect of the dish becomes smaller than the actual offset angle. So when you measure the elevation angle at the vertical dish face, you can take that into account.

LNB skew for 125W should be set at -54 degrees against horizon, as usual at your location. (125W has no pre-skew, I presume?)

I hope this all makes sense, and that I made no errors.
I'll look forward to your results!

Greetz,
A33

Edit:
BTW. Moving from due south to 125W would mean 35.1 degrees motor rotation.
I'm not sure if it would help when you move the motor 35.1 degrees west, and then mount the dish somehow aiming due south?
So when you rotate back to zero, that you can more easily find 125W?
Just thinking out loud; I have difficulty visualizing this...

 

[Need2learn]

Well more then likely that H2H was not designed for your area, so you are going to have to do a WORK AROUND you said 99 is the lowest you can go. I would start your setup around 125w and see if you are able to stay in the arc using that degrees.

 

[swyman18]

Cool, thanks... I will look this over and digest it before I give it a try. Unfortunately, I was careless and broke my lnb connector yesterday so I’m waiting for a new one to arrive before I try anything.

 

[Titanium]

A STAB HH90 is spec'd +/- 72 degrees of rotation. For most regions of the world, this is coverage almost to the visible horizon. If true South is 155w, the HH90 rotation is supported to approx 83w.

If your STB only supports USALS calculations to +/- 55 or 60 degrees, set the motor control mode to DiSEqC 1.2 and you should position the additional 6 degrees to go lower to the horizon.

For elevation angles lower than 10 degrees, the atmosphere can severely attenuate KU. Humidity, heat and clouds will interfere. In theory, you should be able to "see" down to approx. 75w. In reality, you would need a very large reflector, clear, dry and cool weather and footprints that cover your region. In my opinion, a 90cm motorized dish will be useful for your location, down to approx. 87w.

As long as your location has nothing blocking the horizon over the ocean, 87w should be within the range of the HH90 using DiSEqC 1.2 motor control.

 

[swyman18]

A STAB HH90 is spec'd +/- 72 degrees of rotation. For most regions of the world, this is coverage almost to the visible horizon. If true South is 155w, the HH90 rotation is supported to approx 83w.

If your STB only supports USALS calculations to +/- 55 or 60 degrees, set the motor control mode to DiSEqC 1.2 and you should position the additional 6 degrees to go lower to the horizon.

For elevation angles lower than 10 degrees, the atmosphere can severely attenuate KU. Humidity, heat and clouds will interfere. In theory, you should be able to "see" down to approx. 75w. In reality, you would need a very large reflector, clear, dry and cool weather and footprints that cover your region. In my opinion, a 90cm motorized dish will be useful for your location, down to approx. 87w.

As long as your location has nothing blocking the horizon over the ocean, 87w should be within the range of the HH90 using DiSEqC 1.2 motor control.

Hi Titanium.

That’s what I thought also, however using DiSEqC 1.2 control from my receiver, the motor won’t move beyond 65 degrees on the motor scale. According to the HH90 manual, the electronic limits at +/- 65 and mechanical limits set at +/- 70. I’ve confirmed that all limits are disabled in my receiver under the DiSEqC 1.2 setting.

I wonder if the motor itself is limiting me to 65? Do you know if there is a way to change that in the motor so I can get the full +/- 72 degrees rotation?

 

[Titanium]

When we used to provide tech support for STAB products in North America, the hardware and electronic limit was +/- 72 degrees. Maybe changes have been implemented during past 10 years. If DiSEqC 1.2 does not allow movement past this point, there must have been a design change.

If you are not concerned about the warranty, crack open the case and see if the limits can be disabled. If logic controlled, probably could be hacked.

Most of the Chinese HH motors can be opened and the mechanical limit slugs removed for +/- 80 degree movement.

 

[swyman18]

Yeah, I took a chance and opened the case.

I don’t see anything physically stopping the movement, but I didn’t want to risk taking anything apart further.

From the sound of the motor, it does sound like it is stopping electronically at 65 on both ends. And what I mean by that is, it makes the same sound as when I hit Stop on my receiver during any other point. If there is something stopping it physically, I would expect it to sound a bit different, but maybe not.

Anyway, I will continue experimenting. Looks like the SG2100 motor allows you to adjust the hardware limit to 75 and I don’t see any mention of preset electronic limits. Perhaps I should have gotten that motor to begin with.

 

[a33]

In that case I would set the motor at due south, but the dish already aiming east on the motor shaft.
That way the motor axis rotates still at the proper angle, and I think the dish also follows the eastern part of the arc as it should.

Thinking about this further, I'm not sure if the bend in the motor-shaft would mess things up, there. So that that might not work.

An other option would be, to set motor and dish perfectly in line, but with the zero more to the east.
I think I've read some (long) time ago a post by B.J./wejones, where he described that. I found post #6 here: general declination
I'm not sure, if this is the post I remembered, or if he has written more often about it also in other threads.
This would mean that you can follow the arc from zero to 65 degrees rotation; I think set-up at a fictive zero with the angles: declination offset angle as it should be, and motor elevation lower than at due south.
(But it might also be, that you'd have to tweak heavily the elevation/declination combination. This is a setup that I have never seen described in detail....)


BTW. If you have a motor that rotates 72 degrees to east/west, when setup to due south, you'd get to about 91W.

Greetz,
A33

 

[Brct203]

another option, certainly not ideal, would be to offset the LNBF. For example, have the dish point at 99W but move the LNBF a bit to the West to make it receive a bit further East, like a secondary LNBF in a multi-feed system. Again, not an ideal option but certainly better than not receiving it at all. Might also be an easy way to "test the waters" and see if you can actually get those satellites that are low near the horizon

 

[a33]

No physical limit switches visible in the STAB HH90 in this document:

https://www.vga-sat.com/forumimg/STAB/HH90TEST.pdf

or here: DiseqC Motor internal comparison pictures - SatsUK

Not really ontopic, but I'm curious:
How then, in these motors, do they guard the limits?

A33.

 

[Titanium]

No user adjustable limits on the HH90 model like on the Chinese HH motors. There is a design hardware limitation and a logic position calculated off of the default center. This is why I suggested that a hacker could likely open a logic limit to allow additional rotation to a hardware limit.

I am sure that I disposed of the repair manuals / schematics a few years back. I'll see if any of the service manuals remain in storage.

 

[Tron]

A little off topic but still related, Brian, what is your opinion of the STAB motors vs the Chinese motors? I have a few different Chinese motors, but I always get slack problems with them, as well as issues with the plastic covered buttons failing due to weathering issues here in New Orleans.

 

[Titanium]

Comparing the HH motors which are produced and available today, I only recommend STAB motors. While they have their minor issues, they are mechanically superior.