HELP!! - Losing channels and BER Rates going up!

[blueuk808]

Any help is massively appreciated before I start!

Setup - Motorised 90cm dish with Dreambox 500 using Enigma image

I've installed my satellite system and had it working well for about 2 years. Just recently, I've noticed a bit of a reduction in recepetion quality. This seems to have just got worse and worse until today I'm losing channels pretty majorly!

I have just done a service search and it's come back with about 1500 service - as opposed to the 10,000 plus I was previously getting. I have reloaded by bouquets and I managed to get most of the channels, but then randomly all Sky channels just dropped. Where as BBC and free to air channels on 28.8e have SNR 87% AGC 99% and BER's at zero, channels like Sky One have dropped to 60% / 99% and varying BER's. This is happening to varying degrees on all satellites.

I'm trying to work out whether the different transponders on the same satellite can vary in reception so widely, or whether if you get a good reception on one transponder you are likely to get reasonable reception on all transponders of the same satellite.

In essence, I'm trying to work out if my dish needs a tweak or my DM500 is in need of replacement.

As background, I know of 2 areas which may be causing a problem: 1. When installing the dish I found out that the wall where I mounted the dish was not exactly vertical so I had to bring the bottom of the bracket out to get it exactly vertical (or as close as I could get it). I'll be up on the roof later to see if it's moved. 2. I had to join the cable from the satellite inside the house as the cable wasn't quite long enough to make it to the reciever. I have recently replaced the f-connectors so I would hope that isn't the problem.

Would really appreciate any help! Cheers

 

[Analoguesat]

The dish may be misaligned, or there are several other possible causes. These include

-external interference from tetra type transmissions or wifi / dect gear
-poor quality cabling
-water in the cables
-a failing lnb



The cabling and the lnb are the easiest ones to check so start there

 

[blueuk808]

I've had a look at the dish and I think it's ok. I put a level on the horizontal and vertical parts of the bracket and I've made sure the verticle is as verticle as it can be, so I think the fixing of the dish is ok.

The dish alignment - I'm not sure about this as I can receive perfect quality pictures from some channels on a sat but then others are just not there - certain transponders it looks like.

I've tried re-adding channels and it's picking up both horizontal and vertical transponders so I am guessing the lnb is ok.

Cabling - wouldn't that affect all channels uniformerly?

I have recently installed a 5.8ghz video sender in the house along with the usual wifi - I'll turn that off and see what happens but I can't see it being that.

Otherwise I'm stumped. I've tried tuning the channel in via the motor setup screen but no matter how far east or west I go it cannot find the channel.

It's all very odd!

 

[Analoguesat]

Problems with the cabling can cause all sorts of weird problems - internal reflections within the cable, differential absorbtion of different frequencies......

 

[bigfish]

hi, i can confirm you have 2 problems. I am no expert but as the expert says 1 of your problems is somewhere in your setup. Maybe your dish has moved slightly BUT the biggest problem is your DB 500s. I have the same box as you. Gradually i started to lose channels on my box. First i lost certain channels on 13 then a few months later all but a selected few channels would work, basically the tuner sucks in the 500s. How do i know this, well i plugged an old reciever into my setup and it picked up all the channels which were giving me crappy signal strenth and ber spikes on the dreambox!.
So you have 2 problems i think, 1 is the dish is slightly out and the other is your box sucks. I decided to keep my 500s and instead realign the dish. If your dish setup is all correct and pinpoint the 500s is ok it will pick everything up. If it is not then the dreambox will fail to recieve channels that other boxes recieve fine!.

I am sure i am right as i have noticed this trend in my system for a long time and over the last month i have pinpointed these 2 problemds with my setup. I decided to realign the dish more precisely rather than buy a different box.

 

[blueuk808]

I'm starting to get the feeling that it's a dish issue. Looking at 28.8e - on transponder 10714/22000/H I have SNR at 87% and AGC at 99% with no BER. As I go through the transponders to the other end of the range - 12730/611/V the SNR gets progressively worse and decrease to 49%. Does this sounds like the dish isn't aligned correctly? All the channels are very hit and miss.

 

[blueuk808]

Thanks Bigfish!

I had an idea that might be the case. I having odd isues with the box crashing occasionally and the network side of things hanging as well.

I might get a professional satellite installer out to check the dish as I am concerned over the bracket. In the long run it won't do any harm I guess. If that's the case then it's a new dreambox I guess. The problem with the bracket is that the wall of the house isn't perpendicular, it's on a slight slant where settlement has occured over the years. to compensate I propped the bottom of the bracket out with some coins so that the arm of the bracket was as horizontal as I could get it with a spirit level. I checked it today and while the arm was horizontal, the vertical post seemed out, so I adjusted it, but it doesn't seem to have made that much difference. I might give it one more go and see what I can do.

The only other thing I could do to test is to plug the cable into my sky box and see what sky picks up - only concern is then I mess up my sky box!

 

[Analoguesat]

You are safe to move the sky box BUT unplug it at the wall before disconnecting anything, & reconnect the cables before plugging in again.

 

[blueuk808]

Yeah - think it's the dish. Plugged the cable into socket 2 from the 90cm dish and left the sky feed in socket 1. I could get Sky Sports 1 and record it and then change to BBC1. When I swapped them round, I couldn't get Sky Sports 1 but I could get BBC - which is similar to what was happening on the DM500. So it's looking like a verticle issue with the dish. Question is whether to move the bracket or the verticle alignment on the dish - guess get the bracket as verticle as possible then manually fine tune with the dish adjustment

 

[rolfw]

Change the bracket for a set of T&Ks, more substantial and easy to get plumb.

 

[blueuk808]

Yep - was definitly the dish. Must have just sunk a little. Have used the most technical means at my disposal and pushed the roll of 2p's high up under the bracket. Obviously this was after disconnecting EVERYTHING, trapsing upstairs, setting it up in the bedroom so I can look through the window.....

Turns out to me a minor bend in the bracket because I'm supporting it from the bottom to get it vertical.

Don't u just love satellites!

 

[blueuk808]

So I'm watching Sky Sports this morning - fine for an hour - then the BER rate starts to go up and the SNR drops from 91% to 65%. Lose the picture so I turn the TV off. Go back to it 20 mins later and it's back perfect.

There are no trees or obstructions behind the house, nothing has touched the dish, the cables haven't been moved.........

I have no idea what is going on!

 

[Analoguesat]

Is it raining heavily out to the southeast? Rain attenuates the incoming signals.

 

[blueuk808]

Nah - there was no rain. A little overcast, a bit windy - feel like Michael Fsh now.....

I bit the bullet and got an engineer round to test the signal and he reckons it's fie - tested a couple of different sats so looks like the arc is fine too (he complimented me on setting it up too - flattery will get him everywhere).

So looks like it's the DM500. I reflashed the box with the latest Gemini image (4.4?) a few months back and again over the weekend (It's a genuine box so should be ok). I don't have my null modem cable so flashed it over the network with Flash Wizard - just wondering whether the image might be causing the problem and shifting over to another image might help?

Otherwise, I'm going to have to replace - and trying to decide between the 600 or the 7020 - anyone any thoughts?