Ghost channels on Freeview/Saorview and signal problems!

Dave72

I live in the Newry area and recently bought a new Samsung smart TV. My long standing aerial set up for Freeview/Saorview includes an 8 element Group B (yellow cap) UHF aerial and a 16 element Group C/D (green cap) with a diplexer showing (Thru Leg K21-50 / COM / C-D52-68) which also has a sticker that indicates THRU LEG K-CD 50/52.

The Group B is pointed at the Newry South relay (3 km away) and the C/D is aimed at Clermont Cairn (quite a distance away but in line of sight).

Now, I've had absolutely no issues with this set up for decades as regards Analogue>Digital switchover or retuning for newly added channels (recent one was Challenge on Saorview). Signal strength and quality have always been high. Only recently the Samsung TV has been displaying some odd behaviour as regards reception. Interference (blocking) recently appeared on a lot of channels intermittently and I started to receive what I can only describe as ghost channels way up in the 800's where Saorview RTE stuff starts. What I mean by ghost channels is actual copies of Freeview channels BBC/ITV etc where I wouldn't expect them to be. Then yesterday my Freeview reception quit completely. Saorview was unaffected. I tried retuning but no joy. So I checked the aerial set up, swapped out the cables to run the Group B aerial on the common feed cable and got the Freeview signal back. Therefore decided it might be something to do with the diplexer. I disconnected the diplexer and just have the Group B.

Now, funny thing. Ive got my Freeview back AND I'm receiving Saorview over the Group B alone and with a good signal strength even though its not pointing at Clermont at all! BUT ... the ghost channels are still there! Samsung TV indicates that "This channel does not exist. Do you want to delete it?"

Can anyone shed some light on this?

Might I be receiving some interference/spill from another transmitter on a different frequency perhaps?

Any insight would be greatly appreciated!

The Cush

The group C/D aerial is now obsolete, it's frequency coverage range is now used for 700/800 MHz mobile broadband. I wonder if there is some inward interference?

The aerial recommended for Clermont Carn now is Group K - UHF 21-48. All Freeview and Saorview transmits between UHF 21-48.

The Group B also extends into the lower part of the 700 MHz mobile band.

I wonder if a single Group K will work for both transmitters without the diplexer.

Duplicate Freeview channels could be coming from another site.

What are the Newry frequencies?

Elvis Hammond

https://www.boards.ie/discussion/2058294377/ghost-channels-on-freeview-saorview-and-signal-problems

50/52 diplexer is no use now, & the aerial connected to the C/D leg will have its signal attenuated significantly. You can't use a diplexer there now, as the frequencies from both transmitters are interleaved.

Clermont Carn is no distance from Newry given its power output, so you'll probably do fine leaving things as you have them now. I'd check for water ingress in the aerial cable though, given the Freeview failure.

The 'ghost' channels I'd just ignore.

EDIT: I had a look at BBC reception info., & Newry South was off air from about 9 to 6 yesterday, if that's when your Freeview disappeared.

Dave72

Thanks for the input guys. Yes, I think i'll just leave the aerial as is for the time being as the signal is good and everything is working as it should. The setup is in the loft so I'm sure there's no water in the cables.

As for the ghost channels... maybe these are coming from the Camlough mountain site? I remember reading somewhere that it had been switched off for many years and maybe its been switched on again recently? I could be wrong. Or, it could be that the Samsung tuner is just very sensitive and picks up everything around!

Here's what I found with a web search:

Freeview HD transmitter: Newry North, Multiplexes: 3, Height: 89m, Power: 0.002kW, Channels: 40/43/46, Polarity: Vertical.

Freeview HD transmitter: Newry South, Multiplexes: 3, Height: 98m, Power: 0.004kW, Channels: 41/44/47, Polarity: Vertical.

Freeview HD transmitter: Camlough, Multiplexes: 3, Height: 372m, Power: 0.5kW, Channels: 50/55/59, Polarity: Vertical.

These are all Freeview Lite - no public service broadcasting (PSB) and do not provide commercial (COM) channels:

p.s. Anyone want to buy a diplexer and aerial? 😉

Elvis Hammond

It's probably just that the TV regularly scans for new channels & saves these duplicates, maybe during times of enhanced signal propagation. (Usually caused by high pressure weather.)

Camlough I think only started transmitting TV in the last 20 years or so, but wasn't switched off at any point. (And it uses chs. 40, 43, 46 now.)

Dave72

As a side note: why are there just three MUXs on these transmitters instead of the six that are available from the likes of Divis? Is it a technical limitation of the transmitters or a licensing limitation?

I'm sure that everyone in the Newry area who cannot pick up Divis would welcome an upgrade to the six MUXs. Especially given the cost of a TV license!

dxhound2005

I presume the difference between Full Freeview and Freeview Light/Lite. From memory only Divis, Brougher and Limavady are Full Freeview, the rest are Light (like Camlough, Kilkeel, Rostrevor and a lot more).

I am not qualified to comment on the ghost channels, but google seems to think they could be coming from a tuner in a PVR, if you have one.

Elvis Hammond

https://www.boards.ie/discussion/comment/120539321#Comment_120539321

I'd say there would be frequency availability problems now, & probably were even when the full band was available, & then there's the commercial muxes 'bang for your buck' angle, trying to cover the most people from fewest transmitters.

Not sure how the PSB/com divide came about the way it did; I assume Freeview's roots in pay services has something to do with it.

The Cush

Editing the post as I write, remembering stuff from maybe 20+ years ago.

Iirc wasn't it 2+4 muxes initially - OnDigital/ITV Digital - then 3+3 muxes Freeview? From a limited number of sites because they were sharing with the 5 analogue TV channels

I recall an Ofcom consultation, prior to DSO, mid 2000s?, where the commercial mux licence holders were offered the option to be available from all 1,100 sites post analogue switchoff, but turned it down, probably not financially viable.

There is/was 80 full sites, and one 4 mux site, in Wales iirc, used as a test site for the transition from analogue to DTT. I assume this continues.

In hindsight this has worked out well with the reducing spectrum available to broadcasting. Imagine having to squeeze 6 muxes at all 1,100 sites.

Dave72

No PVR here, though I did find an interesting thread about a similar problem on Sony TVs.

https://community.sony.co.uk/t5/home-cinema-projectors-players/pvr-keeps-finding-duplicate-channels/td-p/1762375

...and here ...

https://www.tvanswers.org.uk/answers/freeview-channels-numbered-800-onwards.html

Seems the problem may well be signal from another transmitter. An attenuator might sort the problem out though a better fix might be a LOG periodic to reject side interference?

NorthDown2

My parents have an old Sony TV - non HD, bought early 2010s. When it is retuned, most channels are placed in the 800s. A real pain to put the stations into the correct numbers! I have two Sony TVs - from 2013 / 2014. Both handle channels fine - they have software for iplayer etc which the non HD tv does not. (They put UK channels where they should be and RoI channels in the 800s) So it seems to be a fault that exists in older Sony TVs that are before a time of tv connecting to the internet.

Gerry Wicklow

Freeview sets will put the UK channels in the correct position. Unexpected channels such as duplicates from another mast are considered "foreign" to that region and are placed into the 800's. Saorview are likewise considered "foreign" by the Freeview software.

Dave72

https://www.boards.ie/discussion/comment/120547899#Comment_120547899

Yes, it would seem that there are quite a few duplicates on my TV at the moment up in the 800's.

The whole issue of digital TV's saving Saorview channels into the 800's is a right pain in the arse. They're always in a right jumble. I also note it has a common glitch. The EPG never seems to update properly when scrolling from Freeview to Saorview listings. I always get a 'No Event Information' message or similar beside each Saorview channel. The program info will not update without going to the EPG, selecting a Saorview broadcasting channel in the 800's, exiting the EPG and going back in again to get the listings to update. What's that about?

Gerry Wicklow

Once again that is simply the nature of the beast. If the TV is Saorview compatible and you set the country code to Ireland during initial setup, it would place the Saorview channels in the correct order 1, 2, 3 etc and you'd find the Freeview channels in a mess. You are dealing with two completely separate networks, neither of which knows or cares about the other. The Freeview network carries EPG data for Freeview, you cant expect it to carry Saorview EPG data and vice versa. It would be the same for someone on the south coast of England. You wouldn't expect Freeview to carry French EPG data even if the TV could receive French channels.

marclt

What you could do is reset and do a manual tune on the the relevant frequencies. Can’t remember if Samsung has a way of turning off looking for new channels which may cure the ghost channel issue.

kazoo106

All the hidden Saorview empty nonsense channels / placeholders will show on a TV in the 800's who's region is set to UK