Dish install is flakey. How to troubleshoot?

[guapoharry]

I have a Fortec FC90P dish and DG-280 motor with standard LNB and Fortec Classic NA receiver.

Here's the info from Dishpointer:

Your Location - (not really but close.)
Latitude: 33.582°
Longitude: -112.136°

Satellite Data
Name: Powertech DG240
Distance: 37023km

Dish Setup Data
Motor Latitude Angle: 33.6°
Azimuth (true): 180.0°
Azimuth (magn.): 168.6°
Declination angle: 5.5°
Dish elevation: 30°

I set the motor latitude to 33.6 (half way between 33 and 34) and the dish elevation to 30. The dish was mounted on the motor shaft at zero and pointing to zero per the directions.

With the motor mount loose on the pole, I eyeballed true south from a compass. After some trial and error, I found a TP on my true south sat 111.1W and adjusted the dish for the best quality. It works, but only sort of...

I can see stuff on 129W, 123W, 101W, 97W, 89W.

87W was really flakey. I could only see two feeds, but not the other stuff. A tree is near that sat, so maybe that is the problem there.

On 123W, I can get stuff on TP 11720, but only at 40% quality - watchable. On TP 11800 quality is 33% or less - no good. TP 12114 is also 40%.

I have readjusted several times and that's about the best I can get. The LNB is new. The cable to the motor is new. The cable between the motor and the LNB was OK the last time I used it. The dish was bought new, but it was stored for a year or two before using it.

I rechecked the motor mount for plumb. Using an angle finder, if shows 90 degrees in both directions.

The dish was checked for warp. Face down, it layed flat on a concrete slab.

One thing that is weird is that the dish elevation is only 22.5 degrees, not 30 degrees as the instructions recommended. When the dish is adjusted to get best signal, the dish elevation is 22.5.

Could the LNB arm be bent? How could I check for that?

What else could I check for? Ideas?

 

[satcom1]

I am probably the last person to give advice on a h-h motor after all of my troubles withthe Digipower SG2100. What it sounds like is that your motor is not tracking the Clarke Belt. It is high on one end and low on the other. Did you zero the motor first? when you connected it did the motor move. It is best before you hang the dish to zero reset the motor and make sure that it is reading zero. Check out the threads on the SG2100 problems there is alot of info there.

 

[Wescopc]

One thing that is weird is that the dish elevation is only 22.5 degrees, not 30 degrees as the instructions recommended. When the dish is adjusted to get best signal, the dish elevation is 22.5.

Many dishes are off by as much as 10 degrees - I installed one that was off by11 degrees!. You will need to adjust the motor elevation (latitude) slightly up/down with a corresponding adjustment to the dish elevation until you track the arc. Go to this site: http://www.geo-orbit.org/sizepgs/tuningp4.htm
near the bottom of the page is a set of diagrams showing how to adjust to the arc. While this page is written for "C" band BUD's the principal is the same for KU FTA dishes.
Good luck
Bob

 

[satcom1]

A helpful tool I made up was a dish face protractor. I have a 76 cm dish so I took a 1x4x4, found the center edge and push pinned a protractor to that edge. I took a thread and a Water Gremlin Dipsey SWivel Sinker (Made in USA) and pinned that to the pivot point on the protracter. Now because I have an offset dish I had to do a little Calculas, True South satellite Galaxy 28 should be 42.2 degrees minus the 24 degree offset equals 18.2 degrees for the plumb bob string reading. I got fancy and put a 3/4 inch conduit clamp on the top edge of the board so it would hang on over the dich rim.

 

[satcom1]

I made up a dish elevation micro adjuster out of a 5 inch long eye bolt. Threaded it thru the dish motor tube so it was touching the dish bracket. I tried to post a picture of it but can't use any editing functions on the toolbar, maybe cause I'm new to the forum.

 

[Lak7]

As Satcom1 said - It sounds like you are not tracking the arc.
If 111 is your South(center) you are only seeing about 21deg each way.

Pick the last Sat you get, like 123, then:
Re-check pole for plumb, as the Dish moves, it can pull it out of plumb.

While on 123, make small adjustments, maybe just pressure on the Dish - Left / Right, Up / Down and if there is any improvment, make note of which way made the improvement, and try to return to orig. position.
Then pick the last Sat in the other direction, like 87, and do the same, make note of which way made improvement.
See pic attached....

 

[Lak7]

Satcom1- to post a Pic, use the "New Reply" button on the left vs. the "Post Quick Reply"

 

[satcom1]

LAK7,I tried that and it didn't work. maybe I have somtething wrong in my browser. I tried advanced also all iget for any function on the toolbar is a ballon and no action.

 

[satcom1]

All four of the Digipower SG2100 h-h motors I've tried to get runnig had motor tube allen head metric cap screw that needed tightening. I noticed the dish was flopping back and forth from east to west travel.

 

[guapoharry]

Did you zero the motor first?

Yes.

when you connected it did the motor move.

Yes, it moved a little west. (At first, I was trying to use Satmex at 113 for my TS sat.) Then later I found I could see the TP on 111.1.

It is best before you hang the dish to zero reset the motor and make sure that it is reading zero.

Yeah, I did that. (Not sure how you hang the dish to zero other than to eyeball it.)

Check out the threads on the SG2100 problems there is alot of info there.

Which thread? Did you start it?

Thanks for the input.

 

[guapoharry]

Many dishes are off by as much as 10 degrees - I installed one that was off by11 degrees!. You will need to adjust the motor elevation (latitude) slightly up/down with a corresponding adjustment to the dish elevation until you track the arc. Go to this site: http://www.geo-orbit.org/sizepgs/tuningp4.htm
near the bottom of the page is a set of diagrams showing how to adjust to the arc. While this page is written for "C" band BUD's the principal is the same for KU FTA dishes.
Good luck
Bob

Thanks. That site is good. I will read the page over a couple of times. That URL is 404, but it's not far off. Footprints by Dish Size - Adjusting the Polar Mount for Prime Focus Antenna - C/Ku-Band Satellite Systems - Tuning, Tracking, Azimuth, Elevation, Declination Angles, F/D Ratio, Focal Distance, Inclinometer, LNB/Feedhorn Assembly, Actuator Assembly, C

I see how the principal is the same, but there's no separate declination and elevation adjustment. The declination looks to be a function of the angle built in to the motor shaft combined with the motor mount elevation. If you change the motor mount elevation, the dish elevation will have to change also. (Not like I know what I'm talking about here, just thinking out loud)

So to see where you are at, you get things lined up on the best true south sat. Then, point at sats on one end of the arc, tug on the dish up, down, east, west, and see how that affects the signal and quality Then repeat this on sats on the other side of the arc.

Then with the diagram Lak7 posted, a pattern should result whether the declination is too much or too little, the true south is off, or the elevation is high or low.

Whew.

I have some homework to do now...

 

[Wescopc]

I think you got it!!
Good Luck - and keep us posted
Bob

 

[satcom1]

Look in th e FTA PC dvb section. there is a long running hstory of SG2100 motors with problems. I had one motor that zeroed at 4 degrees west and would never track the arc. Most of my trouble shooting was before I used this forum. There were threads about two years ago about the 4 degree west problem. DMSI is still sending these motors out as repaired replacements but still go 4 degrees west at zero. you canalso do a site search for sg2100 or h-h motor.

 

[Hotrodphil1]

Start with the motor instructions. Inside it will tell you what angle to set the "Motor" at relative to it's mounting bracket, based on your geographic location.

 

[Hotrodphil1]

Set your motor elevation to your latitude of about 33deg and your dish elevation to about 23 or 24 deg. If you have an offset dish then reduce your Dish elevation, Not the motor elevation. Set the motor elevation where it should be and Only adjust the dish elevation. These are different settings, do not mix them. If the Motor elevation is off it Will Not track Properly.