High SNR on Communal Dish - Have I Caused it?

F

Flory

New Member
Messages
4
My Satellite Setup
Octagon SF8
My Location
UK
Hello all,

I wonder if anybody could share their knowledge with me.

Just over a year ago, I moved into a new apartment in a block with a communal dish. There is a triplex wall plate in the living room with connectors for Satellite, TV, and FM radio. In the bedroom, there was a diplex wall plate with feeds for TV and FM radio only.

Having experienced some picture breakup on the television in the bedroom, I decided to replace the wall plate there with something that was better screened....Then I had an idea (!): I decided to see if the cable feeding this socket was carrying the satellite signal like the one in the living room, so I replaced the diplex plate with a triplex one. Everything seemd to work perfectly for over a year. However, recently I have experienced a low SNR on specific channels (clustered around the same frequency) on both the living room and bedroom satellite feeds. I have a horrible feeling that I may have caused some damage to the communal system by tapping the cable in the bedroom for an extra sat feed. Does anybody know if this is likely to be the case? I keep thinking that maybe there was a very good reason why the orginal plate did not have a sat feed, and that I may be somehow overloading the communal system. Nobody else in the block has reported problems, thank goodness. Any advice would be really useful. Thanks in advance.
 
Analoguesat

Analoguesat

Administrator
Staff member
Messages
46,704
Location
Scottish Borders
My Satellite Setup
TM 5402HD
Skybox F3
Sky+ UK.
My Location
Scottish Borders
Welcome to the forum!

These sorts of problems are notoriously difficult to diagnose but we will have a go :) heres some ideas - hopefully someone will chip in soon with some others.

What frequencies are you having problems with? There are known problems with some thanks to dect phone interference, or have any new mobile phone masts gone live in the vicinity recently?

The other thing to check is that the cables inside the rooms of the house are undamaged - if one has got trapped, or a pet animal has been chewing it, or for any reason its got water in it you can get all sorts of attenuation at one frequency
 
F

Flory

New Member
Messages
4
My Satellite Setup
Octagon SF8
My Location
UK
Hi, thanks for your reply.

The frequencies below are showing 0 AGC (for what it's worth) and 0 SNR in the Signal Finder utility:
12090 V
12070 H
11934 V
11914 H.

11954 H and 12051 V look to be quite noisy (SNR fluctuating rapidly between 3.8 and 5.5 dB, compared to between 8 and 14 dB for other channels).

I'm not aware of any new phone masts going up, but will try to find out. Checking the cables is now also on my to-do list for this evening! Thanks again.
 
Analoguesat

Analoguesat

Administrator
Staff member
Messages
46,704
Location
Scottish Borders
My Satellite Setup
TM 5402HD
Skybox F3
Sky+ UK.
My Location
Scottish Borders
What receiver are you using - I have similar problems with a handful of tp's on my TM5402 - channels Im not interested in so Ive never really bothered investigating.

One more thing to check as well if you can get to the dish - make sure any outside cables are not frayed through & cable joints havent lost their waterproofing so the cables arent full of water - I watched in complete astonishment once when I disconnected a cable and over a pint of water dribbled out as the cable joint waterproofing covering had failed!
 
F

Flory

New Member
Messages
4
My Satellite Setup
Octagon SF8
My Location
UK
It's an Octagon SF8. Interesting that it's possible to lose tp's like that. It has been running quite slowly recently which has made me think about an upgrade - this might give me a good excuse! (I'll think twice about a Vu+, having noticed your sig!).
 
Analoguesat

Analoguesat

Administrator
Staff member
Messages
46,704
Location
Scottish Borders
My Satellite Setup
TM 5402HD
Skybox F3
Sky+ UK.
My Location
Scottish Borders
The Vu is disconnected & sitting in disgrace in the spare room junk pile as it failed a couple of weeks ago!

If the box is a few years old it might be worth disconnecting the leads & popping the top off. Study the capacitors (the cylindrical cans with K or T embossed into the top) and see if any have any signs of leaking or the ends distorting especiallay around the incoming power supply. If you do this keep your fingers well clear - no idea about the psu arrangements on that box but modern switched mode power supplies can carry enough charge to spoil your day for quite a while after disconnection from the mains!!
 
F

Flory

New Member
Messages
4
My Satellite Setup
Octagon SF8
My Location
UK
I shall definitely take a look. Cheers again for the help.
 
A

A nonymous

Well-Known Member
Messages
3,586
Are you in the UK or somewhere else in Europe?

Its more than likely the people that built the flat only installed a TV/FM plate in the bedroom is purely down to cost nothing more. Changing the plate wont make a scrap of difference as every cable that comes from the headend will most likely be a multiplexed sat/uhf/dab signal, you wont have caused any issues by fitting the plate.

Its more than likely that the dish has moved or there is an issue with the multiswitch feeding your property. If it was a cable issue its likely that the problem would be across all frequencies and polarities, not just a certain block.

I would just leave things alone and report the issue to whoever is responsible for the tv system. If you mess with the set up and damage it you could end up with an expensive bill.
 
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