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AcousTech
06-10-10, 08:20 AM
Hello SAT Gurus!

First time posting so I hope I don't violate any guidelines here. And I do apologize for the long post. I'm trying to provide all the detail I can. Here is my situation. We live in a suburb of Seattle. A few weeks ago our HD service just cut out totally. It may have been after a storm, but I can't recall for sure. Prior to that we would have occasional pixelation, but generally signal was OK. That's been the way things have gone for the last 3 years. HD reasonably fine for that time and then nothing.

So I called DirecTV and they sent out a tech(after getting me to sign up for their maintenance plan for a year). He took one look at our environment and said the problem was line of sight. Now it is true that we have a lot of tall trees around us, but that doesn't explain why signal goes to 0 all of a sudden. Like I said - we've had HD for 3 years. So he told me it could be the LNBs that had gone bad on the dish itself. We had the old sidecar 5 LNB model. Unfortunately he couldn't replace the satellite dish because current mounting guidelines require two monopoles and in my case there isn't a place for those. So he didn't replace my dish.

Because of where I live cable isn't a realistic alternative. They'll charge $11,000 to isntall it, so I'm inspired to try to make DirecTV work. I went ahead and bought a new Slimline 5 dish and installed it myself. I got the coordinates, made sure my mount was level, set AZ, EL, and Tilt (134,32,108). I got signal back to about where it was with the old dish. Incidentally I did find a way to get one of the monopoles installed, but I think that's just gravy. Anyway, I called the tech back and he came out to aim it for me. While he was aiming it with the Birddog I asked him if he did the combination of the 101 first, then the 119 along with the dither process. He said that honestly all he ever did was lock in the 101. The numbers are below. While he did get the signals much stronger than I had,sadly, my 99c strength is still 0(one transponder on 99s did show 27, but that was it).

His suspicion is that the following things could be wrong in order of likelihood:
1. LNBs on the new dish are bad
2. Cables between the dish and receiver are bad
3. Receiver is bad

He didn't have a replacement with him to be able to test replacing the LNBs. I swapped receivers to test the cables. No difference there. The only items left to test(apart from the LNBs) are the B-Band converters, and the receiver itself.

So all of this sets the stage for my question. I don't believe that my signal strength went to 0 overnight because a tree jumped in the way all of a sudden. I'm OK with strength not being great(we are surrounded by trees after all), but occasional mild pixelation to nothing at all seems too extreme to me. So, does anyone have any suggestions? Is this an aiming thing, or would one of the other items be the more likely culprit? If it is an aiming issue, should I try the dither process myself - even if I don't have a signal strength meter? I've read that without the right meter you may not be able to get what you are hoping for. Anyway, signal strengths below. Anyone have any ideas for me?

Thanks in advance!

101 Tuner 1
80 84 81 0 80 92 82 89
80 85 80 0 8 94 80 95
71 99 79 0 81 94 80 92
82 0 77 99 80 94 78 95

101 Tuner 2
79 83 80 0 81 92 82 90
80 86 80 0 82 95 80 95
77 99 78 0 81 95 80 93
82 0 78 99 80 83 79 95

99c Tuner 1
0 0 0 0 0 0 0 0
0 0 0 0 0 0

99c Tuner 2
0 0 0 0 0 0 0 0
0 0 0 0 0 0

99s Tuner 1(for what its worth one of these did show 27 at one point)
0 0 0 0 0 0
0 0
0 0 0 0 0 0 0 0

99s Tuner 2
0 0 0 0 0 0
0 0
0 0 0 0 0 0 0 0

103cb Tuner 1
92 93 91 89 89 91 88 88
89 89 90 89 90 90

103cb Tuner 2
93 94 91 88 89 91 88 87
89 89 90 88 89 90

employee3
06-10-10, 12:52 PM
Based on them being completely 0, either rerun sat setup or more probably a bad LNB.

hilmar2k
06-10-10, 12:53 PM
I vote bad LNB.

eakes
06-10-10, 01:44 PM
Since both antennas with different LNBs gave similar results, it would appear the first diagnosis was correct - line of sight problem. The 101 readings are lower than they should be by several points, 99 is missing, 103 is normal. This implies to me that there is a tree to the left of the antenna that is causing the problem. The tree leaves are partially blocking 101 and completely block 99. If you live in the country and have a shotgun, do a little 'tree trimming' and see if your levels don't improve.

Stand behind the dish and sight over the feedhorn, there should be a tree to the left of the antenna that is the culprit. Solutions are to trim the tree or move the antenna to a spot with clearance.

RobertE
06-10-10, 03:19 PM
I'm not likeing your 101 levels. A little low for me. Now that could be poor aiming, or the trees have actually blocked out the 99 since they have leafed out and are now ecroaching on 101 a little.

Have you bypassed your multiswitch if you have one? Different set of BBCs?

AcousTech
06-10-10, 08:47 PM
Hmmm. The tree in question _is_ to the left of the dish. However it is a cedar and doesn't leaf out per se. I was thinking a similar thought though. Could be that since two different dishes have shown the same result maybe something in the trees _did_ change? Not sure if I can do any trimming, but I will take a look at that. I don't have a multi-switch and I don't have any spare BBCs. BTW, the reason that tree trimming will be so hard? My dish is already mounted 5 stories in the air. The area to trim? Higher still!

Out of curiosity - are the satellites all at the same elevation? I get that they are distributed across the sky at 99 - 119 degrees. Just wondering if the 99 is higher or lower in relation to the other ones?

Davenlr
06-10-10, 08:48 PM
99/101/103 are going to be within a few tenths of a degree of elevation different, at most locations. 110 and 119 will be lower.

Now, Ive never seen a tree cause the signal to go from good to 0 overnight. Usually the first symptom will be pixellation when the wind blows the branches around. I suppose the moisture content of the needles could have increased quickly, but it would be helpful to know what your signal was like say, a month ago. The 101 signals are a bit lower than I would expect, considering your excellent 103 signals.

You can rule out BBCs if both tuners have the same levels.
You said you swapped LNBs, so that rules that out.

That leaves the trees, or some bad corroded connectors on your ground block, or a diplexer somewhere in the coax chain between the LNB and the receiver.

AcousTech
06-10-10, 09:38 PM
OK.

Connectors are all clean
No diplexers in the coax chain(solid cables from dish to DVR)
Which leaves the trees. Given that this is Seattle there is more than enough rain for moisture content to increase! I suppose the trees and branches may have gotten fuller since it is spring/summer now. Unfortunately I don't have signal strengths from any earlier time to compare this too. I think I'll be putting in a call to a tree trimming company and see what I can work out.

Davenlr
06-10-10, 09:47 PM
Given that you are getting 101, and the difference is only two degrees, is the any chance you could relocate the dish two degrees further west from its current location?

I tried to find a lunar calculator, but was unable to. Perhaps someone on the board here can link one to you. You basically enter your lat/long into the calculator, select the satellite (99.2W) and it will calculate all the times that the moon will be at exactly the same spot in the sky, and give you the date/time. You then go up to the dish at that time, and sit in front of the dish. You will then be able to see if there is a tree between the dish and the moon. You can do this with the sun as well, but that wont be until next October.

AcousTech
06-10-10, 10:01 PM
Hmmm. Nowhere else to move it to. Furthermore, when I go look at the trees it _seems_ that 103 is actually more blocked than 99. What's up with that? 103 is more blocked, but gets better signal? I confess this - I don't understand the different between Ka and Ku, and I'm not sure which satellites are on which band? Does that come into play here? is 99 on a more sensitive band than 103 and therefore is more subjected to this occlusion? Or are they both on the Ka band which just adds to my confusion?

AcousTech
06-10-10, 10:14 PM
Oh, and another question. If the satellites are at 99, 101, 103, 110 and 119, why is my azimuth at 134? I would have expected it to point somewhere in the middle of all of those, but I'm obviously missing something.

john18
06-10-10, 10:49 PM
Oh, and another question. If the satellites are at 99, 101, 103, 110 and 119, why is my azimuth at 134? I would have expected it to point somewhere in the middle of all of those, but I'm obviously missing something.

I think the answer is that those are the longitudes at which the satellites are parked and depending on your physical location will depend on the azimuth that your antenna needs to be pointed to get the proper signals.

Davenlr
06-11-10, 06:32 AM
I confess this - I don't understand the different between Ka and Ku, and I'm not sure which satellites are on which band?

There are three major satellite bands, C band at 4 GHz, KU band at 12GHz, and KA band at 18 GHz. The gain from the reflector (dish) increases as the frequency increases, so for example, to get the same gain as a 36" KU dish, would require a 10 FOOT dish on C band, which is why the Direct Broadcast satellite services use the higher bands, as they can use the smaller dishes.

Now for rain and clouds, C band for the most part has long enough waves that raindrops do not interfere much, so you could watch C band right through a thunderstorm. KU is closer to the size of a raindrop, and the rain will really screw up the signal. KA is closer yet, and suffers the worst from rain.

Trees leaves contain water. The same water that affects the signals because of rain. The more water in the leaves (needles), the worse it will affect the signal. Branches are totally filled with water, and completely block out the signal.

Satellites 99 and 103ca, and 103cb are KA. They have the worst attenuation due to water. They are also the three satellites used for almost ALL the High Def stuff. 101, 110, and 119 are KU, and are used for Standard Def, guide data, and international programs. The fair a little better when shooting through marginal conditions.

So, thats a simple explanation of the KU, and KA differences.

As to your problem. The numbers ,99, 103, etc, are the longitude where the satellite is sitting over the equator. If you were exactly at 101 degrees west longitude, your azimuth setting would be 180 (for direct south). The further either side of 101 you get at your home, the more or less azimuth will be from the 180 mark. The dish is designed with 101 in the center, and the other satellites to either side, kind of bounce the signal off the dish at angles. So, as you stand behind the dish looking at the LNB, the one in the center with three lobes...the lobe on the right that bounces off the dish to the left is the 99 LNB.

What you may have to do, if possible, is find a spot on your property that can see just the 99, 101, and 103 slots (a rather narrow band), and replace your LNB with a SL3, and not worry about 110, and 119 (which doubtfully are providing any programming you want anyway).

The only way to really know, is to use a scope on a tripod next to the dish, set its elevation to match your satellite elevation setting with a inclinometer, and set its azimuth for the true azimuth to each satellite and look through the viewfinder. If you see anything but sky, you have a problem.


Dave

sungam
06-11-10, 10:01 AM
99/101/103 are going to be within a few tenths of a degree of elevation different, at most locations. 110 and 119 will be lower.



From the Pacific Northwest, 119 is actually higher in the sky (~35 degrees) than 99 (~31 degrees).

Try using www.dishpointer.com to see your LOS to 99W in relation to the tree.

BattleZone
06-11-10, 11:29 AM
http://i593.photobucket.com/albums/tt20/BattleZone/sl5-large1.jpg
DirecTV SL5 LNB

Note that the dish is centered on the 101 satellite, and the 101 LNB is at the center of the dish, with the other LNBs on either side.

This is an SL5 LNB with 110 and 119, which are off to one side. If you were to remove those two, you'd have an SL3 LNB, which is symetrical:

http://roxsat.com/shop/images/products/sl3s.jpg
DirecTV SL3 LNB

AcousTech
06-11-10, 05:32 PM
Geez are you guys a wealth of knowledge!

Davenlr - what a great, patient, and thorough coverage. Thank you!
Sungam - understanding the different elevations is definitely helpful too. Especially as it relates to understanding the relationship between my dish and the trees. If I read what you wrote properly 99 will be lower in the sky - and thus trees are more likely to get in its way.
Battlezone - a picture is worth a thousand words. Those are great clarifiers. Thank you too!

Now, I think I have one last question. Dishpointer.com says that the magentic asimuth for sats 99, 101, and 103 for my location is 134.7. Would a poor mans solution to this just be to go point my compass at 134.7 degrees from North(magnetic) and see what is between me and the sky? Would that be fair? Basically just follow the compass path(+/- two degrees - 99 is magnetic 132.6) and see what is in the way(such as a large cedar or two) between me and any of those satellites? I think I understand the Dishpointer.com site line of sight checker to be saying that, in the case of 99.2W, an object 163.8 ft away from my dish could be 97.4 feet tall(from the base of my dish mount) and not get in the. Figuring out the hight of objects starting at the high of my dish might take the inclinometer that Davenlr mentioned, but at least I'd be looking in the right direction!

Am I on the right track here?

Thanks again guys! You are all so very helpful!

BattleZone
06-11-10, 08:06 PM
Yes, you are right on track. You might also want to take a print-out of the DishPointer screen showing your line of bearing to the 101 sat.