motor/dish signal confusion

[Mr Tony]

I've worked with motorized systems now for about 7 years but even this one is confusing me

SG2100
36" dish (GeosatPro dish)...no arms on the side
true south 93W (loc 93.4)

system been up since August (new roof done) but up for over a year before that with no issues

Signals look decent but to me they were low. Also some feeds at the top of the arc were really low or non existent yet the 30" setup it worked. Swapped LNB to a Sadoun Dual .4 and signals still werent peak. Examples on a Pansat 1500 meter (30 threshold)
PBS was at 60
RTV was 58-60
NBC mux on 72W was 99
Data feed on 74W was 60
ABC News Now was 50 or so
CCTV9 was 90
Macy's on 105 was 88

you get the drift. But it seemed like some feeds were low. Today I scanned 91 and there were 4 or 5 feeds that barely showed 20-25 yet the 30" setup worked great.
Went out and started pushing on the dish. Nothing. But then if I pulled on the bottom of the dish and pushed on the arm of the dish the signal JUMPED...big time. Those 20-25 feeds were now 45 and ones that were 30-32 were now 60. hmmmm...
So I used a couple zip ties to "push" the LNB arm up a little bit. Now checked those same feeds

RTV was 75
NBC mux on 72W was 99
Data feed on 74W was 78
ABC News Now was 75-77 or so
CCTV9 was 99
Macy's on 105 was 99

so they all jumped...but now PBS is down to 25-30 and moving the dish left or right doesnt help

What the heck did I do to screw it up? 125 & 123W are now barely above threshold when they were at 60 beforehand. Did pulling on the arm and helping the center of my arc screw up the far west end? East side (72 & 74) signals went up.

 

[bama1]

Don't know how you have dish mounted but A neighbor with a pizza dish provider lost signal on a dish mounted to eaves. The culprit was the weight of dish and mount caused soffit or whatever trim piece is called to sag/pull away from the house, a couple nails to tighten wood restored the signal. Just another one of the useless piece of information stored in my brain that I thought of right away.

 

[Mr Tony]

nah this is bolted on the roof...as shown below (its the one on the right)...that pic was taken this summer....before we got the snow

 

[bama1]

That splains it all, I don't work right if I hear the word snow!!!!

 

[brentb636]

First I'd do Tony ( forget anything sophisticated ) is check all the outdoor connections for moisture, rust , stray metal filament in connector, etc. I can't say how many times I've been burned by cabling issues. Also check that the connectors on the motor are tight and solid to the motor itself. I had a SG2100 that had one of its connectors pull out of the rf shield, and it was intermittent from that day on.
Good luck, no time to be on the roof, I know.

 

[FaT Air]

Looks to me like all the reference q readings are near center and the PBS is the furthest from center. Moving the arm up will also change the offset angle. I think if the elevation is off, it would exacerbate the problem at points further from the center of the arc. So I'd check the elevation again. Just a thought.

 

[Mr Tony]

I didnt touch the elevation on the dish...thats at 23 which is what it should be on a SG2100 setup (dish at 23 motor at 45)
With 123 & 125 being 30+ degrees off my true south that may be it. 72W is only 20 off and that is fine that way.

eh I might leave it as is. I may have lost 123 & 125 but I gained signal on all other sats from 72-105
(that and the fact its cold and snow on the roof I might leave it til spring)

 

[8valve]

Reading your narrative, I focus in on the following; "Went out and started pushing on the dish. Nothing. But then if I pulled on the bottom of the dish and pushed on the arm of the dish the signal JUMPED...big time. " From this, I believe your dish was slightly out of track. When you did the push/pull thingie, you sprung the LNBF arm slightly. It would not take much to move that LNBF Arm, especially without side struts to support it. By push/pull on the dish/LNBF arm you in essence really adjusted the Polar Angle very slightly, (since you still get partial arc). We only adjust Polar Elevation at Zenith/South Bird. Being out of track, in my opinion, is documented by the fact you get good Q at 72 West to 105 West. PBS at 125 West is low Q, because your running slightly out of track. These dishes are too wimpy, especially without side struts supporting the LNBF arm to try to bend her back, your libel to do more damage. I suggest leaving the LNBF arm where is and drive the dish back to your Zenith Bird/Sat, peak Q with azimuth and polar elevation. Now swing as far west as possible and peak the Q with azimuth only. Drive back to Zenith, peak Q with polar elevation. You should be good to go. Now drive her between your maximum birds and if necessary go back and readjust as mentioned above. Proper, Polar Elevation adjustment (tracking) should compensate for the tweak of the LNBF arm. 8Valve

 

[Mr Tony]

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)

 

[Magic Static]

Ice, you just described the alignment of my Ku Dish, I too find good signal on the eastern side but not good if I dial in PBS. Since Montana PBS and other PBS feeds are local channels for me I have sacraficed them for the others. After reading the sticky on aligning a KU motor, I believe I have the answer and got ahold of one of Walrus1957's Adjustment Adaptors to help fine tune this dish. Like you, I have a delay for winter weather and unable to complete a couple of my FTA projects this season.

Montana Sate (#4 seed) lost to North Dakota yesterday. Now I don't know who to root for in the FCS playoffs.

 

[Mr Tony]

Montana Sate (#4 seed) lost to North Dakota yesterday. Now I don't know who to root for in the FCS playoffs.

yeah I watched that game yesterday...that was actually the feed I was referencing above

 

[Larry1]

Your mounting poll may need supports. You may not see any movement, but it only needs a slight bit to put the dish out of alignment. You may check by measuring the distance from the top of the poll to the top of the poll of your other dish with it postioned in the centre and at both extremes.
Also, running a piece of the braided fishing line, (the kind that advertises as no stretch, not monofilament) from the holes in the side of the dish to the LNBF arm may help eliminate any movement of the LNBF arm as well.

 

[Hermitman]

If your house is a wood stick construction with a truss and plywood roof, it may be the moisture content of the wood because of winter. Winter really drys out the wood and that can cause shrinkage which will alter the various angles of house walls and roofs (although slightly). Or maybe, the antenna mounting bolts are shifting because of shrinkage, especially if they were removed for the new roof. Good luck.

 

[AcWxRadar]

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