Over the last few months the HD freeview on BBC 1, 2,ITV and C4 have been a bit flaky with frequent dropouts and several days with no signal at all. It appears these channels are all on the same frequency (ch54). All other channels are fine including the other HD channels.

 

Could this be the aerial failing? This doesn't appear to be a transmitter problem or TV oroblem as both H D freeview devices have the same problem .

Maybe worth trying to fit another adapter on the end of the wire see if that fixes the issue.

 

Have neighbors reported the same thing happening?

I had a similar thing recently and it turned out to be the connection cover on the aerial that had withered away so was totally open to water ingress. It all looked fine from the ground as the connections were on the top!

Anyway, I took the opportunity to get a new 'digital' aerial and re-cabled to the distribution amp and all is now good.

Has 4G been switched on in your area? If so it maybe worth looking at this https://at800.tv

Has 4G been switched on in your area? If so it maybe worth looking at this https://at800.tv

 

Seen this and I have a filter - so not that problem.  Just wanted to check the likelyhood of a dodgy aerial  - before |I get soemone out to fix it. The aerial been up for at  least 10 years and might even be as old as the house (1989)  so if it is the original aerial it won't have lasted too badly.

I'd be looking at aerial. In analogue days, transmitters sent out four channels from one transmitter and ch5 (if you were lucky from the same-if not from another more remote transmitter,but in the same aerial group). And then, each channel sent out one program( i.e. bbc1 would be on CH X,BC2 on CH Y etc), but all channels would be in the optimum reception range of that one aerial. These days, we've got channels on a "MUX" SYSTEM, where the BBC channels(1/2/3/4 , and possibly CBBC ETC) are on the same PHYSICAL channel.

That old aerial would be set for group reception from the local transmitter and optimised on that channel group. These days, you might find that the channels you have problems with have been moved to one outside the optimum receprion range of your old aerial, whwre the aerial gain is lower.

For maximum gain, there is a relationship between the dimensions of the aerial and the frequency of the transmitted channel .So if the channels giving problems have been moved to a frequency outside the optimum reception range of your old aerial ,then the gain will drop, as will the signal. And digital transmissions will be OK, till the level drops, giving dropouts and pixelation. it's like tuning a car for max on 98 petrol and then trying to run it on 95.

 These days, we've got channels on a "MUX" SYSTEM, where the BBC channels(1/2/3/4 , and possibly CBBC ETC) are on the same PHYSICAL channel.

 

 

I thought that what could be the problem as it only affecting one old channel (Ch54).

Seen this and I have a filter - so not that problem.  Just wanted to check the likelyhood of a dodgy aerial  - before |I get soemone out to fix it. The aerial been up for at  least 10 years and might even be as old as the house (1989)  so if it is the original aerial it won't have lasted too badly.

Ideally you need a digital antenna to get terrestrial digital with any reasonable quality old uhf/vhf antennas are not as efficient.

I know you say you have a 4G filter but If you can, best bet is to get decent new coaxial cable from the antenna to the TV, as the older coax is not sufficiently screened against the likes of 4G and filters are the last resort a good coax will negate the need for filters in the fist place.

No such thing as a digital aerial.

 

In the early days of freeview, most people's aerials were capable of only receiving a specific set of bands, set for their local transmitter. 

When digital and analogue were transmitted simultaneously, the digital channels were usually "out of band" compared to the analogue channels.

 

"Digital" aerials are simply wideband aerials capable of receiving all channels.

 

It's still just a piece of metal that collects radio signals. Nothing digital about it

If this helps at all? I occasionally have problems with BBC1, but switch over to BBC1 HD which will be fine.

Probably a different channel, as you mention. I have a very old aerial and most viewing is great.

Even get a 3D signal occasionally.

We had this a few years ago and the aerial had turned slightly on it's pole n- was amazing how much a small alignment change made such a big difference.

Most (if not all) tv sets incorporating Freeview have a built in signal strength/ quality check (accessed via "settings" which gives you a graphical read out of the performance of a specific channel. If the output or quality level is down only on channel 54 but OK on adjacent or nearby channels, then it indicates inadequacy of the aerial at that specific frequency OR (more likely) water ingress into the coax cable, either because the aerial cap has come off or chafing of the cable insulation. It only takes a little bit of moisture to completely modify the electrical characteristics of the cable at a specific frequency.

you may find it is all right now, as the high pressure has moved away, replaced by low pressure

it affects the signal coming from the transmitter

I thought that what could be the problem as it only affecting one old channel (Ch54).

Sorry for my ,possibly too technical post, but that was basiclly what I was saying. With the old aerials ,the transmitters were set into groups for BBC1/2+ITV & ch4. CH 5 was often transmitted from another mast. i.e. Locally in my area, we got BBC1/2+itv+ch4   from Sutton and CH5 from Litchfield. One reason for aerial grouping was to prevent problems with nearby transmitters, which in the main used a different grouping, as there was a possibility of transmitters on same frequency causing problems, especially if an aerial recieved two signals of opposite phases, due to transmission delays. As said, an aerial is an aerial , neither digital or analogue, it's tuned to a set frequency ,and recieves signals within limits of equal strength. IF the channels are a of a great difference ( as can be the case with the move to digital transmission), then it might be benifical to look at changing the aerial for a wide band one, which has an equal gain pattern over a wider frequency band.

Edited 5 October, 201510 yr by VWD

The problem with old aerials is that they also have old coax cable. Moisture ingress at the last foot or can affect the loss (often seen as black coating on the copper). Similar problem with the final connection at the aerial.

 

I suggest the time has come to replace the aerial and at the outside length of the coax cable, preferably all it if possible, with a good modern low loss cable and a high gain wideband aerial. Note that most wideband aerials have a lower gain than an old group aerial and may need a wide band amplifier to go with it. Particularly if you need to add a 4G filter for channels 59 and 60 as wideband aerials have less gain at the top and bottom frequencies.

As long as you're actually going to buy from them, (And they are excellent) have a loot at ATV:

 

http://www.aerialsandtv.com/

 

 

These guys have loads of information on their web site, but are quite reasonable and state don't call them for advice unless you're going to buy from them.

 http://www.wolfbane.net/cgi-bin/tvd.exe?

 

Enter postcode to find location, bearing, power, frequency and polarisation of digital signal and a suggestion as to the best type of aerial to use. Also lists the Muxes.

 

My bet would be on the transmitter power being turned right  down whilst they juggle the kit and which broadcaster uses which mux i.e. as it was in London  for 6 months out of every 2 years in the ten years before  the final digital switchover deadline. When they finally made the switch they then put the transmitter on full power and that had the effect of again everybody who'd invested in aerial amplifiers not receiving a digital signal because of signal overload. Post switchover in London, when they are not doing transmitter work at Crystal Palace and its operating at full power (200Kw) you could probably pick-up a digital terrestrial signal with a piece of damp string.

 

Nick

Depending on your box you can often see the signal strength of a channel by delving into the menu. As the channels you mention are all on the same muxi then check on and see. BBC1 is slightly different to the others though as it has fixed bandwidth, although I don't see how this will show as any difference in signal strength.

Well - I think I've fixed this.

 

Nice cheap fix as well after a suggestion by someone on the Digitalspy forums.  I had a ferret behind the TV and separated the aerial leads from the all the other leads behind there ( network, power, HDMI etc) and now the signal strength has increased to 10 on the dodgy channel from the 5 to 0 it was previously.

Ferret should be kept in a cage, maybe time to change to winter aerial?(I'll get my coat I think)

Ferret should be kept in a cage, maybe time to change to winter aerial?(I'll get my coat I think)

 

Winter aerial - it's not below 7deg yet

Winter aerial - it's not below 7deg yet

A winter Ariel only works with VHF  (one for the geeks amongst you )

A winter Ariel only works with VHF   (one for the geeks amongst you )

 

How about an "all season" Ariel - er - wide band  (geeks are us)

How about an "all season" Ariel - er - wide band  (geeks are us)

or just wait for warmer weather to help with the lower frequencies

Winter aerial - it's not below 7deg yet

 

Oh sorry, my bad, but Ski Sunday will be starting soon, though today is only Misty Tuesday - I think (oh bother it is now Wednesday).

 

Anyway, roughly the same topic - ie Telly - I think that you can get "snow covers" for SAT TV LNBs (a random annoying thought - that is all).