Is USALS compensation possible - off ~2 degrees?

[nailpounder]

I have a similar problem with my sg2100 setup with a 36" dish, Invacom Quad LNB and Captive Works CW700s receiver. I hit every bird in the arc from 61.5W to 125W, but 89W is the only sat I hit dead on with USALS. As I go west, USALS gradually drifts off farther west so by the time I get to 125W it's off by 2-3 degrees west. I tried a couple times to adjust it using my southern sat at 103W but didn't have any success. I decided that maybe my pole isn't perfectly plumb along the north-south axis. I use USALS to get the dish close to the sat position I want, then tweek it using DiSEqC and save the position. It really isn't that hard to do and I still get the entire arc.

 

[Lak7]

As I go west, USALS gradually drifts off farther west so by the time I get to 125W it's off by 2-3 degrees west.

I have the same issue, probably caused by a heavy Dish. What I did was add 4 degrees to my Latitude n the USALS setup. If I change the Dish to a much lighter Fortec 80cm, I must use my correct Latitude for it to track properly.

 

[AcWxRadar]

I have a similar problem with my sg2100 setup with a 36" dish, Invacom Quad LNB and Captive Works CW700s receiver. I hit every bird in the arc from 61.5W to 125W, but 89W is the only sat I hit dead on with USALS. As I go west, USALS gradually drifts off farther west so by the time I get to 125W it's off by 2-3 degrees west. I tried a couple times to adjust it using my southern sat at 103W but didn't have any success. I decided that maybe my pole isn't perfectly plumb along the north-south axis. I use USALS to get the dish close to the sat position I want, then tweek it using DiSEqC and save the position. It really isn't that hard to do and I still get the entire arc.

I have the same issue, probably caused by a heavy Dish. What I did was add 4 degrees to my Latitude n the USALS setup. If I change the Dish to a much lighter Fortec 80cm, I must use my correct Latitude for it to track properly.

Nailpounder,

Is the Invacom LNBF that you have a QPH-031? That is quite a heavy device. Also, if your dish's LNBF arm does not have supporting struts connecting the end of the LNBF arm to the perimeter of the dish, the weight of an Invacom QPH-031 can cause the arm to sag in the direction that the dish is driven.

These factors can throw your alignent off just the same as what Lak describes with just a heavy dish.

One of my dishes is a Winegard DS-2076. This dish has no supporting struts for the LNBF arm. When I drive the dish to the far east or west, I can see that the arm sags a little. Or, when the wind is quite gusty, I can see the end of the arm and the LNBF "bounce" and dance around somewhat.

Since the Winegard DS-2076 LNBF arm is fairly sturdy all by itself, this error was never very large (no where near 2 degrees), but it was enough for me to detect a reduction in signal quality.

I fabricated some supporting struts (based on the design of my Winegard DS-3100 dish which did have these struts from the factory) to prevent this. These struts made the entire dish assembly much more rigid all around.

RADAR

 

[Anole]

I have the same issue, probably caused by a heavy Dish. What I did was add 4 degrees to my Latitude n the USALS setup. If I change the Dish to a much lighter Fortec 80cm, I must use my correct Latitude for it to track properly.

Pretty clever trick. You think pole was flexing? Wonder how long it is?
Imagine my concern about this guy mounting a 4' dish 'n motor atop 6' of 2" fence post:

http://www.satelliteguys.us/free-ai...7-my-installation-pictures-2.html#post2101237

 

[B.J.]

Pretty clever trick. You think pole was flexing? Wonder how long it is?...
...

There used to be a fellow over on the Satforums group, who's ID name was 26foot or something like that. He claimed that he had a 26' dish (I was never quite sure what percentage of his claims I actually believed, but he seemed relatively believable on the big dish part). Anyway, he got into a discussion about aligning techniques, and he said that with a 26' dish, that the resolution was so fine, that it was virtually impossible to align a dish that big using the regular polar mount techniques, and it was because of the errors introduced by the pole flexing. Ie, you can compensate for pole flex when facing south via the elevation adjustment, but when the dish moves to the east or west, then the pole starts flexing in that direction, making alignment impossible. He said that he had to use an Az/El system to find sats.

But if you talk about flex, the first dish I ever helped install, was a friend, who mistakenly installed a HEAVY 10.5' H-H, on PVC pipe. That was like trying to cast a bowling ball with a fly rod.

 

[Lak7]

Pretty clever trick. You think pole was flexing? Wonder how long it is?

I think most of my error is the extra weight on the motor, the motor has to have a little "give".

 

[Babadem]

I have the same issue, probably caused by a heavy Dish. What I did was add 4 degrees to my Latitude n the USALS setup. If I change the Dish to a much lighter Fortec 80cm, I must use my correct Latitude for it to track properly.

@ the red Highlighted:
Were the adjustments on the motor mount or on the receiver?

 

[nailpounder]

Nailpounder,

Is the Invacom LNBF that you have a QPH-031? That is quite a heavy device. Also, if your dish's LNBF arm does not have supporting struts connecting the end of the LNBF arm to the perimeter of the dish, the weight of an Invacom QPH-031 can cause the arm to sag in the direction that the dish is driven.

These factors can throw your alignent off just the same as what Lak describes with just a heavy dish.

One of my dishes is a Winegard DS-2076. This dish has no supporting struts for the LNBF arm. When I drive the dish to the far east or west, I can see that the arm sags a little. Or, when the wind is quite gusty, I can see the end of the arm and the LNBF "bounce" and dance around somewhat.

Since the Winegard DS-2076 LNBF arm is fairly sturdy all by itself, this error was never very large (no where near 2 degrees), but it was enough for me to detect a reduction in signal quality.

I fabricated some supporting struts (based on the design of my Winegard DS-3100 dish which did have these struts from the factory) to prevent this. These struts made the entire dish assembly much more rigid all around.

RADAR

Yes, this pretty much describes my situation. I use the QPH-031, which is a heavy lnb. Also what Lak7 said about a heavy dish. I use a Fortec Star 90P dish and the lnb arm doesn't have supporting struts. The lnb arm is fairly rigid, but I used the original roof-mount post that came with the dish and I think the combined weight of the motor, dish and lnb are causing it to tilt slightly southward. At the same time, it has withstood 65 mph winds. Since I'm able to compensate for it and get an average Q of 75-80 across the arc, it really hasn't caused a problem for me.

 

[AcWxRadar]

Yes, this pretty much describes my situation. I use the QPH-031, which is a heavy lnb. Also what Lak7 said about a heavy dish. I use a Fortec Star 90P dish and the lnb arm doesn't have supporting struts. The lnb arm is fairly rigid, but I used the original roof-mount post that came with the dish and I think the combined weight of the motor, dish and lnb are causing it to tilt slightly southward. At the same time, it has withstood 65 mph winds. Since I'm able to compensate for it and get an average Q of 75-80 across the arc, it really hasn't caused a problem for me.

Nailpounder,

If you don't mind making a few adjustments to your coordinates in the menus or to each of your satellite orbital (degree) positions in the box to keep you tracking the arc well then the phrase "if it ain't broke, don't fix it" comes to mind as a thought.

My dish antennas have seen some rough weather here as well. Once there was a storm where the winds were so strong that, and I am not joking one bit, pontoon boats were ripped from their moorings and tossed out of the lake, up onto the beach and thrown several houses down the shore. It wasn't a tornado, but it was a very strong wind storm and I think I recall that the NWS estimated the wind speeds to be in excess of 85 mph with gusts even higher that that, possibly 120 mph based upon their assesment of the damages.

Fortunately, I did not receive these winds. My place was 10-15 miles further north and it wasn't THAT bad here.

Anyway, a little "wobble" in the dish or the LNBF arm isn't going to bother anything for the most part. Especially providing that it always goes back to the original setup position. When the wind starts wrapping your dish around a tree, then you have problems, but I don't think that anyone sells a dish that they gaurantee against that type of force. If the storm gets that bad, you've got more to worry about than your dish alignment! Like maybe how to realign your house to the foundation, if you still have your house!

That wind storm that we had here was so bad that it killed all the rabbits. Yes, it choked them all to death. The wind was so strong that it blew their butts up over their necks and choked them all! Ha ha! Ok, you can boo and hiss now. Lame joke time there.

RADAR