Gibertini 1.25M On Smw Polar Mount

Llew

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Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
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Not having enough forward space on my pole for the intended Gibertini polar mount until I move the pole back (dish arm would intrude over neighbour's property), I have now installed my SMW polar mount on the dish.

At present it is on a temporary 2" ground level pole before final installation on the 3" pole. As far I can tell, the 18" actuator will have no problem moving the dish between roughly a 60E - 60W arc, as the original SMW 1.05 dish/polar mount did; bearings at extreme arc ends were taken with the iPhone Dishpointer app, as at the dish's present position on the ground precluded checking the extreme E/W satellites.

Dish movement along the arc is excellent with this combination, seems to be no obvious strain on polar mount or actuator. Some dry runs for a few days will no doubt show up any signs of distress.

Will be removing surplus metal from the actuator piston pivot bars now, as the position of the pivot away from the centre of the dish seems ideal - time taken to move the dish across the arc is just right.
 

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Captain Jack

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Is the Gibby outperforming SMW?
 

Llew

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Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
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Yes captain, by some degree. A good test was the horizontals on Nilesat 201 - some of these are found with the Gibby given good conditions (usually nighttime), difficult with the SMW dish.

Incidentally, the SMW mount has no declination adjustment; the angle for the UK and north Europe is predetermined in the mount's elevation angle, and can be adjusted by what is quaintly called a 'Tilt Bar' which is (was) provided by SMW for inserting between either the upper or lower mount fixing bracket for latitudes north or south. Not sure of the exact angular range either of the three cover, but there is a little diagram in the SMW installation bumf that shows the areas covered. Without the bar, the area extends from the north of England to the south of France/north Italy. No doubt a different thickness bar would allow a much narrower angle to be defined, but it's perfectly fine as it is without a bar where I am - the middle of the diagram cuts right through East Anglia.
 

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I like the idea of using the smaller pipe at the back of the pole to allow for the use of larger clamps.
 

Llew

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Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
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Yes, I used this method for many years with the SMW PM before I got a 3" pole. It's just an offcut from a TV aerial mast.
 
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Yes captain, by some degree. A good test was the horizontals on Nilesat 201 - some of these are found with the Gibby given good conditions (usually nighttime), difficult with the SMW dish.

Incidentally, the SMW mount has no declination adjustment; the angle for the UK and north Europe is predetermined in the mount's elevation angle, and can be adjusted by what is quaintly called a 'Tilt Bar' which is (was) provided by SMW for inserting between either the upper or lower mount fixing bracket for latitudes north or south. Not sure of the exact angular range either of the three cover, but there is a little diagram in the SMW installation bumf that shows the areas covered. Without the bar, the area extends from the north of England to the south of France/north Italy. No doubt a different thickness bar would allow a much narrower angle to be defined, but it's perfectly fine as it is without a bar where I am - the middle of the diagram cuts right through East Anglia.
I am going to try adapting this the CM120.
A steel adapter plate should work for the attachment, and I think an actuator in a configuration like yours.
However, on declination, can you tell me if the manual indicates that I should adjust the declination with washers or similar?
Also, maybe I have not got my head around the geometry yet, but does the decliation adjusment depend on the offset angle of the dish? What if the CM and SMW are different?
 

Llew

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Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
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The SMW OA1050 has an offset angle of 26.5°, whereas my Gibertini 1.25M is 21.3°.This meant I needed to set the declination angle 5.2° higher.

As I have mentioned, there's no method of adjusting the declination of my Gibertini / SMW polar mount, so I had to fall back on the crude method SMW uses.

I placed a spacer (actually two metal strips, total 7mm) under the bottom flange of the polar mount, as shown in the second pic. Trial and error, but it gives me the correct declination. It was of course necessary to loosen the top flange nuts to enable me to slide the bars in the bottom flange.Retightening them means the top flange isn't quite flush with the Gibertini back plate, but it's perfectly OK.

The SMW diagram (G) shows how the positioning of the spacers correlate with the latitude where the dish resides.

Actuator shown the SMW page is of course the original method of fixing, before they supplied the means of fixing a conventional actuator.
 

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The SMW OA1050 has an offset angle of 26.5°, whereas my Gibertini 1.25M is 21.3°.This meant I needed to set the declination angle 5.2° higher.

As I have mentioned, there's no method of adjusting the declination of my Gibertini / SMW polar mount, so I had to fall back on the crude method SMW uses.

I placed a spacer (actually two metal strips, total 7mm) under the bottom flange of the polar mount, as shown in the second pic. Trial and error, but it gives me the correct declination. It was of course necessary to loosen the top flange nuts to enable me to slide the bars in the bottom flange.Retightening them means the top flange isn't quite flush with the Gibertini back plate, but it's perfectly OK.

The SMW diagram (G) shows how the positioning of the spacers correlate with the latitude where the dish resides.

Actuator shown the SMW page is of course the original method of fixing, before they supplied the means of fixing a conventional actuator.
Brilliant stuff. Thanks for all this info - exactly what I was looking for.
The Cm120 is 22.6 deg (AFAIR), so very similar to the Gibertini, although slightly smaller angle.
I think you are right - trial and error is the way to get the best out of it.
I now need to clean up the mount a bit first, and get an adapter plate made + a fastening bracket for the actuator (similar to the bent pipe you have).
 

Llew

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Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
The Flatlands of East Anglia
Good luck with that st1. Shouldn't be too difficult to make some kind of bracket for the actuator, steel tubing would be ideal if you can get a length and bend it or perhaps a metal fabricator would do it if you have one near where you are.
 
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@Llew: Do you have more pages to share from the SMW installation manual for the OA-1050?

Specifically, I am wondering what the "Area 1 .... 10" means on page 7 of the manual that you posted earlier here: Gibertini 1.25M On Smw Polar Mount

I am looking to continue the re-purposing of the SMW polar mount, but I am trying to understand the adjustment possibilities of the mount, and at this point specifically relating to the positioning of the strut (or whatever it's called) between the lower and upper half of the mount attaching to the back of the dish. There seems to be multiple mounting options - labeled D1 and D2 in the installation drawings.
It would be good to understand what those where, so adapting to a non-SMW dish could use the best configuration for the mount.
 

Llew

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Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
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Specifically, I am wondering what the "Area 1 .... 10" means on page 7 of the manual that you posted earlier here: Gibertini 1.25M On Smw Polar Mount
That's just the various countries in Europe for the adjustment of the elevation bolt ('E' on that page). I'll scan and upload the other pages when I can.

Ah, the strut. Had that positioned wrong for ages until I realised it tilts the upper and lower brackets in such a way that the dish is off vertical, and made it hard to align all satellites perfectly. Corrected with my last install - pic shows the bottom strut bolt in the bracket edge hole, and (hard to see) the top bracket bolt in the inner hole. I don't know why there are different ways to position the strut, it's not very clear in the instructions.

Need some Kurust treatment up there.


Strut Position.JPG
 

Llew

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A lot of the info is a little outdated, especially measurements for the mini actuator. However, here's the instructions, minus some of the European info, just the English and Danish pages. Other map pages are available, but maybe not of much use unless somebody is doing an original install of a 20-year-old dish with a transversely positioned actuator...
 

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That's just the various countries in Europe for the adjustment of the elevation bolt ('E' on that page). I'll scan and upload the other pages when I can.
Ok, thanks.
Ah, the strut. Had that positioned wrong for ages until I realised it tilts the upper and lower brackets in such a way that the dish is off vertical, and made it hard to align all satellites perfectly. Corrected with my last install - pic shows the bottom strut bolt in the bracket edge hole, and (hard to see) the top bracket bolt in the inner hole. I don't know why there are different ways to position the strut, it's not very clear in the instructions.

Aha. Well, I'm not sure mine's set up correctly.
Here's the mine from the other day when I took the reflector off the mount, but before altering anything.
Your description makes sense as I have been wondering about what holes the strut should be mounted at.
But clearly the manual shows that both mountings are possible, but I am hoping I can find out the reason behind each.

IMAG3179_cutsmall.jpg
 
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A lot of the info is a little outdated, especially measurements for the mini actuator. However, here's the instructions, minus some of the European info, just the English and Danish pages. Other map pages are available, but maybe not of much use unless somebody is doing an original install of a 20-year-old dish with a transversely positioned actuator...
Ah, but it does. You see, having access to even the less relevant pages facilitates the grasping of the original design details, and more importantly, their relevance for contemporary use.

For example, the manual spends pages and pages on the effort of elevation adjustment through setting the length of a bolt depending on geographical zones across Europe. I think most people on this forum would agree this is something that takes 2 minutes based on dishpointer starting alignment and some form of digital meter connected.

(Mind you, this is not too different from the Channel Master manuals - things were just a bit harder back then when all you had as a DIY was a tv receiver and a somewhat unweildly large dish!)
 

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Ah, the strut. Had that positioned wrong for ages until I realised it tilts the upper and lower brackets in such a way that the dish is off vertical, and made it hard to align all satellites perfectly. Corrected with my last install - pic shows the bottom strut bolt in the bracket edge hole, and (hard to see) the top bracket bolt in the inner hole. I don't know why there are different ways to position the strut, it's not very clear in the instructions.
Having examined the scans you so graciously have uploaded, it seems that the strut mounting in the upper plate of the mount at either D1 or D2 seems to do with the motor being left- or right-hand mounted (when seen from the back). Left in the UK, right east of the UK (presumably left in half of France - that's got to be in the maps you omitted).

From the text, it seems there is not mechanical difference between the two.
However, scrutinizing the actuator configuration, I can't quite see what the difference is. But I am sure there is one, otherwise they probably wouldn't have gone to all the trouble of making two separate mounting holes at the top.
Is there an aligment difference? Hard to tell...

The bottom mounting point for the strut is different though.
If I understand your messsage correctly, you have now mounted the strut in the edge hole, not the central one.
Well, mine's attached to the central one.

IMAG318130pct.jpg

Do you think it should be attached to the edge one?
It is clear that there will be a slight difference in the angle between the upper and lower plate of the polar mount depending on whether the central or edge hole i used, and a resulting declination difference.
But which set of holes is the right one??

It seems to me, that since we need to adjust the declination anyway for non-SMW dishes, the main thing is the alignment of the lower and upper halves in the vertical axis. This clearly will be affected by using either the central or the edge hole. A better balanced mount will give smoother action across the arc, I assume.

Empirical evidence will eventually prevail, I am sure.
 

Llew

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My Satellite Setup
Triple Dragon, Dreambox 8000, Echostar AD3000ip, TBS6522,6925,6983 PCie cards.
Gibertini 1.25m motorised dish driven by the AD3000, with either Inverto BU Quad or Norsat / XMW Ka LNBs . SMW 1.05m + 3 other dishes. Speccy: Promax HD Ranger+
My Location
The Flatlands of East Anglia
Not sure why I put the bottom of the strut in the off-centre hole. I know I needed that arrangement to obtain a perfectly vertical dish alignment. I've forgotten how I had it positioned when I first mated the mount with the Gibby.
It's certainly tracking the arc correctly now.
Notice how the tilt plate 18 is used to obtain declination according to your latitude. It won't be enough for the Gibby because of the offset differences between the SMW and Gibby dish, so shims will need to be inserted between the bottom bracket and dish. Any other dishes' offset will also have to be taken into consideration.
Unless you can find a better way of adjusting the declination?
 
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