105 interference

[JohnTenn]

Has anybody here come across a problem where the 105 satellite has excellent single strength, but intermittent single loss? Several people in my company have gone on various trouble calls where the complaint is signal problem related to the 105 satellite. We have replaced lnbs, dp34 switches, wiring, grounding, moved the dish, and have yet to resolve this problem.
Attaching a single meter to the fss lnb and adjusting the gain allows you to here a pulsing in the single whenever this problem is present. On the point dish screen it will jump from wrong satellite and jump to over 100 signal strength, and occasionally lock in around 70 like it should. Depending on the time of day, this problem seems to disappear entirely and can not be verified by any means. All I can say is when the problem is present, one variable that remains unchanged is the pulsing single on that lnb. Any advice would be appreciated.

Edit: one other thing, it seems to be worse on transponders below 7, and will generally lock on transponder 11 even when problem is present. The general location for this problem is Chattanooga, TN. I have spoken at great length with various "advanced Techs" at Dish and nobody seems to have a clue.

 

[dlsnyder]

You could start by trying to find a general direction this interference is coming from. When the offending signal is present try slightly turning the dish to see if it increases or decreases. You may be able to localize it that way. I wonder if it could be a second harmonic from an unlicensed consumer device, like one of those new 5.8 ghz cordless phones?

 

[JohnTenn]

I have attempted to "tweak" the dish to try to hone in on the signal as well as hone in on the "pulsing" pulsing is directly proportional to the signal strength. As for cordless phone, I don't know, but you'd think if that was the case it'd only do it while people were on the phone. I do believe that that is the right line of thinking though. I'm certain that something is closer that is similiar in frequency that is causing this. When it first happened, my first thought was ham radio, but the area of effect is so strange. One person can have the problem and another person living within a mile doesn't have any problems.
What is the frequency that the 105 satellite receives on?
Edit: looks to be 11720 mhz according to Lyngsat, so what else could interfere with that frequency?

 

[SimpleSimon]

I have attempted to "tweak" the dish to try to hone in on the signal as well as hone in on the "pulsing" pulsing is directly proportional to the signal strength. As for cordless phone, I don't know, but you'd think if that was the case it'd only do it while people were on the phone. I do believe that that is the right line of thinking though. I'm certain that something is closer that is similiar in frequency that is causing this. When it first happened, my first thought was ham radio, but the area of effect is so strange. One person can have the problem and another person living within a mile doesn't have any problems.
What is the frequency that the 105 satellite receives on?

105 is around 12GHz - http://www.lyngsat.com/packages/dish105.html

I doubt it can be HAM radio - even with harmonics, it's tough to get up there in any strength. 5.8GHz phone is possible, but I don't think it's likely. Radar would be my first choice of culprit.

What's close to the Line Of Sight to the bird? House on the hill with phones? Big white ball full of radar?

 

[JohnTenn]

Perfectly clear LoS, Nothing could possibly be in the way. Radar could be possible, because it seems to me to be at high traffic times now that I think about it. Goes out during day, and comes back up at night. Now next question is how do I prevent it? Is there anything I can put in line to focus the single coming in from the sky?

 

[SimpleSimon]

... Is there anything I can put in line to focus the single coming in from the sky?

That's precisely what the dish itself does. Only thing I can think of offhand is to get an old BUD (Big Ugly Dish) and go from there. It can be done, but it's not easy. An 8 foot dish will give you a LOT better SNR (Signal-Noise Ratio).

 

[JohnTenn]

Switching multiple customers from Super Dish to a BUD isn't a suitable solution. There has to be a way to shield this lnb or focus it in on that transponder.

 

[SimpleSimon]

Switching multiple customers from Super Dish to a BUD isn't a suitable solution. There has to be a way to shield this lnb or focus it in on that transponder.

Of course it's not. But how many customers are living in an area where some oddball interference is taking place?

I assume by transponder, you mean satellite, and of course, my light-hearted suggestion of a BUD does exactly what you say - focuses the signal.

To look at it another way, how many prospective customers can't get E* or D* simply because they live on the north side of a building?

There's simply no way to get a satellite signal to everyone.

 

[dlsnyder]

There are ham radio hobbyists that experiment in the microwave bands so that is one possible area to explore.

Another possibility - how far are your customers from Arnold AFB? It looks like they do a great deal of R&D there, including development of advanced testing techniques for the aerospace industry. Here is a link to check out... http://www.militaryexits.com/military_bases/arnold_tn_afb.shtml

 

[JohnTenn]

My only question would be why does one customer experience the problem and another doesn't. I'm not talking about not being able to get 105 satellite at all. I'm talking about getting a good solid 70+ signal strength and having intermittent signal loss at various times during day. Most customers complain that they lose the local channels (sat 105, transponder 1 Chattanooga locals) during the morning hours. My service area includes all of North Georgia north of ATlanta. What's weird is that if you go 20-30 miles north, the time of day seems to adjust, where locals come in fine until about 11am then go out till about 6-7pm. During the period of outage, placing a signal meter on the line, you can hear a slight pulsing in the signal, which isn't there when the problem doesn't exist.

 

[ats7627]

JohnTenn,

Looks to me like all the Chattanooga locals are on transponder 1 with a satellite frequency of 11720Mhz which is an IF frequency of 970Mhz. The first thing I would do is check the signal off the LNBF with a spectrum analyzer to find out exactly what the offending frequency is. If you don't have a spectrum analyzer, you can rent them, or borrow one from a buddy. Terrestrial interference can be caused by many different things and by not knowing what the offending frequency is, your totally lost. By the way, are all of the problems located in the same general area, or are they more widespread?

 

[JohnTenn]

JohnTenn,

Looks to me like all the Chattanooga locals are on transponder 1 with a satellite frequency of 11720Mhz which is an IF frequency of 970Mhz. The first thing I would do is check the signal off the LNBF with a spectrum analyzer to find out exactly what the offending frequency is. If you don't have a spectrum analyzer, you can rent them, or borrow one from a buddy. Terrestrial interference can be caused by many different things and by not knowing what the offending frequency is, your totally lost. By the way, are all of the problems located in the same general area, or are they more widespread?

I'll check into the spectrum analyzer, don't know anybody myself that actually delves that deeply into electronics. As for the locations, some are 50 miles apart from each other. I have personally been on some where one customers worked intermittently and the customer down the road < 1 mile worked fine. I'll check into the spectrum analyzer and get back with ya. Where might I locate one for this purpose to rent? any suggestions?

 

[Stargazer]

I have been having the same issues as you have along with signal interruptions at times and when there signal interruptions (indicated by the messaging popping up on the screen briefly) I can check the signal strength screen and see where it bounces from 0 to the normal signal range where it remains most of the time and then to 125% occassionally.

I have had others in my area say that they have been experiencing this and some that is far far away from me experiencing this with several customers in an area as well. This is happening with the PrimeStar dish with PrimeStar lnbf as well so this is either interference or an issue with the 105 satellite. There is no issue with the 121 satellite that I have been hearing about.

I am wanting people with these issues to log them so that we can see if there is a pattern even if the distance is several hundred miles from each other. People need to write down the times, the transponder/channel that they had the signal interruption at, and the person's location. Then from there they could be posted in a thread on this discussion board. If everyone that is seeing this problem could view their local channels at the same times each day then we can see the similarities.

 

[big ed]

I had the same problem at my office when I installed the superdish for 105. Turned out it was a cheap radar detector causing the problem. As soon as we unplugged it the signal locked in. It affected it up to 50 to 75 yards away.

big ed

 

[dlsnyder]

That's odd - spurious emissions in the Ku band from a radar detector? I wonder if it might use the same IF as those Superdish FSS LNBs. What brand was it? It could be a widespread problem that could be the cause of all sorts of weird RF anomolies.

 

[SimpleSimon]

Just a thought from the blue here - maybe the coax shield isn't sufficiently grounded allowing RF leakage into the center conductor? It's a long shot, but worth checking I think. The grounding at the receiver end is NOT enough for several reasons, including safety issues.

 

[Stargazer]

Would RF leakage cause two different people at two different locations or two different systems using two different types of dishes have the same channel go out at the very same time? I would think that it would cause a sporadic loss of the signal if that was the case where two different locations would not experience the loss of the signal from the same satellite and same channel at the same time.

 

[SimpleSimon]

No argument - it's just a thought. All things considered, what's the common item? We don't know. Location, installers, equipment? Chances of a true common cause seem low to me - except for the pulsing - and where's that coming from? Whatever it is, if it's not coming from the bird, chances are it has to be bypassed as opposed to removing it. If it's military testing, you ain't gonna get them to stop.

So, do everything possible to improve Signal To Noise Ratio.

 

[Stargazer]

This seems to be the biggest challenge yet to try to figure out what the issue could be. I have never experienced this big of a widespread issue before. I can rule out the follow: receiver because it does it on more than one at once, switch because it does it at more than one installed location at a time, lnbf because it done it using a bigger dish using a PrimeStar lnbf at the very same time as another receiver hooked up to the SuperDish. Wiring because of the same reason, it done it at different locations at the very same time. It is not the station(s) because it does it on different stations on the same transponder and satellite at the very same time.

I have narrowed it down to be the 105 bird or interference in the area causing the problem. Sometimes I also wonder if there could be a flaw in the 301 receivers that make it where it cannot handle such signals where they were made for DBS frequencies but then again I have not heard about any issues with the 121 satellite like this. I have noticed my radar detector going off constantly in a certain area around one of the SuperDishes having the issue with this.

I think there is a way I can narrow it down to whether or not it is interference. If I setup a SuperDish looking at 121 and see if it goes out at the same time as 105 then I would be able to tell if interference is causing it. If both goes out at the same time then I know it has to be interference, but if not then it would have to more likely be the 105 bird. Problem is one can only get the barker channel on 121 unless you subscribe to channels on that satellite and I do not get my locals from that satellite. I would need some stations from 121 in order to test this. Perhaps if someone could have a receiver activated on a different account as an additional receiver that receives content from 121 then one could be able to test those stations (especially if they come in on the even and odd transponders for a further test). I doubt Dish would just turn on a few channels from 121 in order for you to test them. I dont think any of the channels are FTA either are they?

 

[JohnTenn]

This seems to be the biggest challenge yet to try to figure out what the issue could be. I have never experienced this big of a widespread issue before. I can rule out the follow: receiver because it does it on more than one at once, switch because it does it at more than one installed location at a time, lnbf because it done it using a bigger dish using a PrimeStar lnbf at the very same time as another receiver hooked up to the SuperDish. Wiring because of the same reason, it done it at different locations at the very same time. It is not the station(s) because it does it on different stations on the same transponder and satellite at the very same time.

I have narrowed it down to be the 105 bird or interference in the area causing the problem. Sometimes I also wonder if there could be a flaw in the 301 receivers that make it where it cannot handle such signals where they were made for DBS frequencies but then again I have not heard about any issues with the 121 satellite like this. I have noticed my radar detector going off constantly in a certain area around one of the SuperDishes having the issue with this.

I think there is a way I can narrow it down to whether or not it is interference. If I setup a SuperDish looking at 121 and see if it goes out at the same time as 105 then I would be able to tell if interference is causing it. If both goes out at the same time then I know it has to be interference, but if not then it would have to more likely be the 105 bird. Problem is one can only get the barker channel on 121 unless you subscribe to channels on that satellite and I do not get my locals from that satellite. I would need some stations from 121 in order to test this. Perhaps if someone could have a receiver activated on a different account as an additional receiver that receives content from 121 then one could be able to test those stations (especially if they come in on the even and odd transponders for a further test). I doubt Dish would just turn on a few channels from 121 in order for you to test them. I dont think any of the channels are FTA either are they?

You wouldn't need to actually subscribe to any channels, just look at the point dish screen. While the problem is present, it won't lock on the satellite.

As for the other suggestions, the mobile radar sounds the most viable, but why every single day at the same times? Also, in my own case, one person can have trouble, while the neighbor's system works fine. As for grounding, in all cases the dishes are grounded properly at the dish. Generally we come off the dish with all 3 lines, go into a ground block, then to the switch. The ground block is usually grounded separately on it's own ground rod.


Guess I'll continue to strive for a viable solution. Went on another call today with an identical problem. Tweaked the dish to get the highest possible single on the 105 satellite and made no difference whatsoever.