Dish Bracket Reference Marks (1 Viewer)

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cyberham

SatelliteGuys Pro
Jun 16, 2010
3,703
1,731
Nova Scotia
With reference to attached photos, where are the reference marks? For the elevation, I think I see the pointer. But for declination, who knows?

Another way of asking....what angles are set in each of these photos?
20190831_140551.jpeg
20190831_140605.jpeg


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harshness

SatelliteGuys Master
May 5, 2007
16,796
2,844
Salem, OR
These are the elevation scales and I have no idea where the reference mark is but based on the faint shadows, the top one might be set for 30 and the bottom for 28.
 

cyberham

SatelliteGuys Pro
Jun 16, 2010
3,703
1,731
Nova Scotia
There is an elevation angle between mounting pole and motor. There is a fixed declination angle associated with the motor. You then calculate the dish elevation angle based on the motor declination and the latitude where you're located.

My motor elevation angle at my latitude is about 45 degrees. My motor declination angle should be about 7 degrees for my latitude according to motor instructions. So the dish elevation angle is 30 - 7 = about 23 degrees.

I think these photo readings are 30 and 32 degrees respectively. Top is elevation of dish angle. Bottom is motor elevation. I adjusted both angles.

With the pain of getting this inexpensive SG-2100 to track the arc accurately with my fairly heavy 1.2m dish, and with only 72W to 105W of the arc visible, I'm thinking of ditching the motor and just installing two fixed dishes: 87W and 103W.

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cyberham

SatelliteGuys Pro
Jun 16, 2010
3,703
1,731
Nova Scotia
I don't know the design of the Stab 90 but I've heard it's the only one to get nowadays. I am curious how they address the issue of the different angle needed between pole and motor for different latitudes. It probably has more sophisticated software that drives it and that takes care of this variable.

I may give my motor one more chance. My study indicates I may have made a mistake in fixing the dish elevation and tweaking the motor elevation angle. It should be the opposite. The motor elevation angle should be fixed at the latitude of the dish (perhaps plus 0.6 according to some). And only the dish azimuth and elevation should be tweaked for maximum signal. USALS can be used to get near to each satellite with diseqc mode being used for final tweaking.

So for my latitude of 44.7 degrees North, I will set motor elevation at 44.7 + 0.6 = 45.3 degrees elevation. And I will start with dish elevation at 30 - 6.8 degrees = 23.2 degrees (per motor manual) and tune from there.
 

Titanium

AI6US
Lifetime Supporter
May 23, 2013
7,316
8,371
Meadow Vista, Northern California
HH motors require the install location latitude or the elevation angle (90 degrees minus latitude) to be set on the motor bracket. Often, one side of the motor bracket has a latitude scale and the other side has an elevation scale. The manuals for each motor model provides a chart for the dish elevation setting angle. The variable between models is the tube angle chosen by the manufacturer.

If you no longer have the paper manual or unable to locate online, the dishpointer.com website provides the dish elevation angle settings for many models.
 

Cham

VE4GLS
Pub Member / Supporter
Dec 19, 2008
2,386
957
Boonies
Motor to mast elevation angle should always be your latitude (or 90 - your latitude, depends on how the motor is marked). The declination offset is set using the dish elevation adjustment. Then it should track the whole arc. That's how my SG2100 is set.
 
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jorgek

SatelliteGuys Pro
Mar 11, 2013
1,214
221
Near Toronto
Isn't the goal here to adjust the dish elevation for max signal and quality once the latitude is set on the motor. Whats the declnation for? You still have to adjust dish elevation. Setting up USALS, I set the motor to the 0 reference mark, position the motor and dish assembly to point to my nearest south sat. Then I drive the dish/motor to the nearest sat with known active transponders. I adjust the dish elevation to the sat elevation. Finally tweaking the azimuth, by moving the entire motor and dish assembly on the mast, and then tweak dish elevation. 9 out of 10 times this procedure works very well.
 

Titanium

AI6US
Lifetime Supporter
May 23, 2013
7,316
8,371
Meadow Vista, Northern California
The manual chart puts the dish elevation angle in the ball park, then the dish elevation is optimized for peak SQ. Some refer to the dish elevation angle as setting the declination. I have always found this term to be confusing as some installers would then try to incorrectly adjust using the BUD polar mount declination tables to the angles provided in the manual charts.
 
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jorgek

SatelliteGuys Pro
Mar 11, 2013
1,214
221
Near Toronto
I always assumed that setting declination was for polar mounts only and not off set dishes. But every manufacturer ( 2?) of H-H motors have their methods.
 

Magic Static

FTA Geek
Lifetime Supporter
Oct 12, 2010
7,428
4,750
Montana
What is confusing about declination on a Ku motor mount is the offset of the dish. The dish has an offset value. The motor shaft has an offset value (bend) that compensates for the offset of the dish. Both these values are unknown to most users. Now you add ( or subtract) the declination to those values to figure where your dish should be pointed.
These angles are illustrated in the post I wrote about converting a polar mount to hold an offset dish. ? offset angle Primestar 1.2m
 

cyberham

SatelliteGuys Pro
Jun 16, 2010
3,703
1,731
Nova Scotia
Thanks for all the feedback. I now have adjusted everything correctly and have so far observed operation from 72W to 125W. I have stopped swearing at my innocent motor which is behaving satisfactorily. Two PBS satellites with 125W Montana PBS at 80% quality! This is how a 1.2m dish should function. All satellites in that range are being received even those I thought were below my treeline. The breakthrough was when I locked the motor elevation correctly at my latitude and only varied the dish elevation for maximum signal from satellites.
 

jorgek

SatelliteGuys Pro
Mar 11, 2013
1,214
221
Near Toronto
When I first started going down the road with the H-H motor, I incorrectly set the LAT on the motor. Took a while to figure it out. Getting the mast perfectly plumb and setting the LAT are critical to properly tracking the arc.
Good to hear you got it sorted out!
 
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