Aerial Issues

Teej202

Member
Dear experts,

I'm looking for some advice re Freeview reception and aerials.

I live in a Georgian mid-terrace building made up of nine flats. On the roof is an aerial (pictured below through my alarmingly mucky Velux window!). Using Google Maps I've determined that it's pointing practically due South. I believe the Aerial has been in place since the mid-noughties. I believe it supplies signal to nine flats, though in reality only five draw signal from it.

  1. Does it matter how many people draw signal from it? If more people are connected to it, does the strength diminish?
The TV I have connected receives very poor signal, while another of the four flats whom I know are using it receives excellent signal - all channels without any problems.

2. Could this be due to the cable from the wall to the TV? I have replaced it to check, but there is no discernible difference in the signal received.
3. Having eliminated the problem of my cable, what could the issue be? If we're all receiving signal from the same source, why is mine so poor compared to others', and is there anything you can suggest I do to improve it?

Many thanks

IMG_7429.JPG
 

Rodders53

Distinguished Member
Location (approximate) town/vllage/suburb at least. Ideally a postcode within 100 metres, but not your own - a shop, pub, church or school will be ideal.
That'll allow us to estimate transmitter and likely signal levels.

That is not one but three antennas (aerials) stacked one above the other far too close together so they will interact radio-frequency wise with unpredictable results. Antennas must be spaced at least a metre from any other to avoid that problem

They are also 'high gain' X-bay types that Jason of ATV aerials calls 'bacofoil' aerials, but those look undamaged so far.

Likely it's three flats fed from each antenna via a passive or powered splitter?? Or some other combination to suit the floorpland layout.

Who is responsible for maintaining the communal shared antennas system(s)? It may entail reading the lease and talking more to your neighbours about the issue.

The outlet socket on the wall may have developed a poor/loose connection. So worth gently checking that (although it's usually the communal system's property / responsibility). It's also possible that a powered amplifier has failed or been turned off somewhere. Again your neighbours may know a bit more?

Has it ever worked properly for you?

A properly designed antenna distribution system can supply hundreds of outlets and it matters not if outlets are connected or not to receivers.

Fly leads of poor quality can affect signals and hand-made plugs and sockets can frequently need re-making properly. Wiring up plugs, aerials and wall plates - A.T.V. Poles, Brackets, Clamps & Aerials is worth a read.

If you've just moved in have you checked if your TV needs retuning having moved from one transmitter to a different one?
 

Teej202

Member
Hi Rodders, thanks for your reply.

Approx location is W1H 5HA

The aerials were originally on a party wall and were moved without permission during some building works. They paid for the reinstallation of them in their current place. I'm not sure if it was then that they were stacked one on top of another. Your information that it's not ideal is very useful, thank you.

I think the reception in this flat has got worse over time. It is worse too, for instance, when the Apply TV box is powered on.

I will investigate with the building management re your other suggestions. Though I would be very surprised if these had a power amplifier.

I've retuned the TV several times, at different times of the day and in differing weather conditions. I still don't get the full gamut of channels.

I'm currently using a Samsung TV from Singapore, I imagine the fact I only get about 5 channels through that is more to do with the tuner than the antenna. For the avoidance of doubt, I do have another TV made for the British market that experiences the same problems, though I certainly get more than 5 channels on it!
 

mikej

Well-known Member
If you put your postcode and house number in the checker on this site, it'll give you a list of possible transmitters and what to expect in terms of signal coverage, although it obviously won't take into account any local factors that may affect your signal like nearby tall buildings, trees etc.

Using the postcode you gave above, it looks like you're not too far (around 12km) away from the Crystal Palace transmitter and the coverage prediction for all the Freeview muxes is excellent so you at least know that you stand a chance at receiving a decent signal, provided the aerial is of a suitable type and correctly aligned, of course.

According to the Freeview channel checker, you could expect to get the full complement of Freeview channels in your location, so around 142 in total (including radio stations).

What are the signal strengths for the channels that you do receive ? There's normally an option to check in the tuning or set-up menu. You'd need a TV with DVB-T and DVB-T2 tuners and be able to scan from UHF Channels (frequencies) 22 to 55 in order to receive SD and HD channels from the Crystal Palace transmitter. Those UHF channels would be covered on a UK-spec TV but it might be worth checking the manual tuning menu of your Singapore TV in order to see what you might expect from an automatic scan on that TV.
 

Rodders53

Distinguished Member
Central London Oxford Street / Marble Arch area. So undoubtedly Crystal Palace if not obscured by some taller buildings. South(ish) pointing confirms same --- actually it'll be more SouthEast as bearing predicted is 147 degrees. {183 degrees (South) is Reigate and that's vertically polarised, so not with those aerials.}

BBC HQ isn't that far away. ;)

Check the wallplate for poor or broken connection.

Somewhere in the bulding there will be a device called a splitter (passive or powered) between the aerial cable(s) coming down and the dwellings... three of them probably. The cables and connections to them need checking also - particularly those feeding to your dwelling.
Powered amps would likely be supplied from common parts lighting / smoke alarm / door entry power. But for 3 or 4 dwellings from one aerial there's no need for amplifiers in that part of London.
 

Teej202

Member
So, I had previously tuned using the automatic tuner and never had much luck. I tried manual tuning - individually on each frequency group from 22 - 55 (from 482000 KHz to 746000 KHz with bandwidth 8 MHz (the other choice was 7 MHz)). It was tedious, but I've got far more channels than before. Though no channels were added on groups 30-55 other than from on 35 (586000 KHz).

The channels are all over the place on the channel list, which really isn't important for me for my use, but it is somewhat interesting. Possibly due to the Singaporean nature of the TV?!

No HD channels have come through, but I'm now guessing the tuner isn't capable of it!

Thanks for your help and advice. The reception is still patchy, but I can watch the news now without too much difficulty!
 
Last edited:

A1944

Well-known Member
To save you searching them all again any time, the channels for Crystal Palace are:

23, 26, 25, 22, 28, and 35 (all SD - DVB-T)

30, 55 (HD DVB-T2)
 

Teej202

Member
To save you searching them all again any time, the channels for Crystal Palace are:

23, 26, 25, 22, 28, and 35 (all SD - DVB-T)

30, 55 (HD DVB-T2)

Haha, that's very useful. At least it marries up with my experience, which is comforting!
 

wongataa

Well-known Member
Hi Rodders, thanks for your reply.

It is worse too, for instance, when the Apply TV box is powered on.
That sounds like you are getting interference from the HDMI lead connecting the Apple TV to the TV. Move the cables to keep the aerial and HDMI leads as far apart as possible.
 

Teej202

Member
That sounds like you are getting interference from the HDMI lead connecting the Apple TV to the TV. Move the cables to keep the aerial and HDMI leads as far apart as possible.
I'll try to, but they're pretty close by nature. I'm going to take the faceplate off the aerial socket to see if the connection is a bit dodgy and see if I can improve it.
 

Rodders53

Distinguished Member
Most TVs have a signal level and quality meter built in (signal diagnostics).
That can indicate if the aerial feed to your flat is OK or not up to par. But I suspect it's the foreign set issue.

UK TVs have Freeview branding / testing to meet the specific requirements - that includes the Logical Channel Numbering to get BBC 1 on 1, BBC 2 on 2 etc.,.

Unless the set allows selection of the UK in initial setup it's unlikely to work as well as a proper UK set. (Things like digital text / red button and even perhaps subtitles and audio description may not be supported.)

According to Wikipedia
Singapore
Following a small-scale trial by the state-owned Mediacorp (which holds a monopoly on free-to-air broadcasting in the country) and pay television provider StarHub, Singapore announced in June 2012 that it would adopt DVB-T2 as its digital terrestrial television standard, determining that it was best-suited for Singapore's urban environment. By December 2013, Mediacorp had launched digital simulcasts of its channels. The analogue switchover occurred shortly after midnight on 2 January 2019.
So you may need to specify that mode of DVB-T2 when tuning? (ch 30 and 55).
My Humax PVR needs that doing on a manual tune?

Unless it was a very early DVB-T only set (dig out the manual/spec sheet for it?).
 

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