yeah not having those side struts on that dish has hindered me before. This is before they were made on the Geosat 36" dish. Maybe in spring I'll make some for it
oh well....This whole thing started because on the 30" dish the feed I wanted to watch (NCAA FCS playoffs) was way better than the 36" and I wanted to free up the 30" for more scanning

(the 30" has a Coolsat 5000 on it...the 36" has a slow old Pansat 2500 with slow as molasses blind scan....both are hooked to azbox for HD/4:2:2 feeds)
Ice, when I first started with FTA I purchased a Winegard DS-2076 dish. It came equipped with the side struts for the LNB arm. I later attempted to use the DS-3101 dish (a 1 M dish) and it did not come equipped with the side struts. I robbed these struts from one of my unused DS-2076 dishes and put them on the 1 M dish. The mounting holes were already pre-drilled from the factory and that left me curious why they didn't send the struts with the dish in the first place.
That satisfied my problem there, but I had other problems with the Winegard DS-3101 dish. It was very finicky with the alignment and the focal distance for the Invacom QPH-031 LNBF that I was using. I am sure that everyone will identify with the fact that this Invacom LNBF is very heavy (if I recall correctly it weighs 1.2 lbs). That alone is a problem. The 1 M Winegard dish was also quite heavy and it really taxed my SG-2100 motor. The mounting bracket of the 1 M Winegard dish was intended for a pole or mast mount and not a motor tube, so I had problems there, too.
I just gave up on the 1 M Winegard and 6 or 8 months later, I purchased the 1.2 M GeoSatPro dish from Brian at SatelliteAV. Now this dish set up nicely! I posted my episode details about that installation here and I am sure that you probably read it. That dish came with the side struts. I don't have any problems with the alignment of the LNBF with this dish (focal position) but I do have a problem with the wind loading and the size of the dish. To obtain the most perfect LOS for the entire horizon, I have installed my dish in a most unprotected location. It is therefore at the mercy of nature's wrath. It shows. When the wind direction is just right and strong enough, it "flutters" my dish and I can detect that small change in my quality level. If it is really bad, it actually cuts out the signal for a split second or so. Just enough for my displayed video to actually drop out. This is an extreme condition, it is usually just fine, but you understand where I am leading towards here.
Any dish without the side supporting struts for the LNBF arm are going to be much worse. If the dish and LNBF arm can move enough to cause problems in a high wind storm with the struts installed, there will definitely be a problem if the struts are not installed. So, you are right in this aspect for certain.
In your case here, it does not sound like the wind is affecting your alignment so much, it sounds like it is a permanent alignment problem. My brother and I found that two of our dishes had a bent LNBF support arm. We did, or rather my brother did, find that there was an error in the manufatcuring of the LNBF support arm. On his Winegard dish, it was off very far, the bend angle where the support arm curves under the bottom of the dish was off several degrees. That really fouled us up for a long time and we did not figure this out until my brother compared the new dishes against the old. He saw this difference and went checking and determined that there was indeed a bad lot of LNBF support arms produced for a short time. Some of these dishes (or LNBF support arms) made it to the consumer before they found the error and corrected it. You can tell immediately by looking at the assembled dish if you have a bad one... The elbow or the bend that curves just below the bottom of the dish should be approximately 1/2 inch or slightly less. On a bad one, it will be more than one inch away.
This is not your trouble in this case, though. You have a totally different dish. I just mentioned this so that you can identify with the problems that we have discovered in the past.
I do believe that your trouble is an alignment problem, however. It could be the dish alignment itself, the LNBF focal point position or even the motor positioning. I wouldn't place a bet on any one, but I would place a bet on all four. FOUR? I only mentioned three. Ha Ha! Yeah, I will also keep my betting options open for the cable and switch connections, too!
RADAR