Missing Freeview HD Channels

[PeteCarpenter]

Hello,

For a while we've been losing the terrestrial HD channels - BBC, ITV, CH4 etc. Basically all Freeview channels from 100 - 200.

The issue seems to be with our BT TV box, and I was convinced it was a faulty 'arial in' connection on the back of the box. I came to this conclusion after much fiddling around and investigating, and being able to repeatedly retune our LG television successfully directly by bypassing the TV box and just plugging the aerial cable into the telly. Incidentally we have a loft mounted HD aerial and are just a couple of miles from the local TV transmitter (Harnham, Salisbury). So the signal is strong, and we never had issues losing channels in the past with BT.

I chatted with BT live support last week and they sent out a replacement box, but the problem remains.

Again, I can retune the telly directly and get all the channels, and even if the aerial cable is plugged into the BT TV box but the box is off, the telly receives all the channels. As soon as the box is powered up, those HD channels disappear.

So the problem is clearly with the signal going through the box when the box is powered on. Any ideas please?

Many thanks,
Pete Carpenter.

[NigelB72]

Check the signal strength and quality your box is receiving through the app. If either are too high, it can cause issues that are easily rectified by fitting an adjustable attenuator. These are available for a couple of quid from Amazon etc 

[TimCurtis]

@PeteCarpenter 

As @NigelB72 has mentioned it's very highly likely that the signal strength is way too high so an adjustable attenuator between the aerial plug and the BT TV unit's aerial in socket will solve the problem.

You're looking for a signal quality of 100% and a strength of ,say,  85%. Tune into 1 of the usual SD channels and adjust the attenuator until you get around the figure I've mentioned and then do a retune. Hopefully all will be good after that.

[zulu17]

Another possibility  is  interference  to the aerial cable  from other cables or devices. Most common is where Hdmi and aerial cables are in close proximity.

[PeteCarpenter]

Hi,

Many thanks for the replies. Signal strength is around 60%, quality 100% on several of the SD channels. So maybe the signal isn't as strong as I thought. Can an attentuator increase strength or only reduce? Sorry, not familiar with that device!

There aren't any other cables in the vicinity other than those necessary for the BT TV box, and the main cable from the loft aerial isn't split anywhere.

I just find it odd that we never had the problem before with the same setup.  And if the television itself doesn't suffer, surely the signal strength must be ok?

Cheers.

[NigelB72]

@PeteCarpenter an attenuator can only reduce. If you signal strength has dropped only recently it's possible that some damage may have been caused by the heavy rains over the last week or so...  Could be worth getting a local aerial chap/chapess out to have a look... 

[PeteCarpenter]

Hi Guys,

Just to update on the missing Freeview HD channels - still no joy. I've tweaked and tweaked until I've got an 85% signal strength or so, but the BT box (brand new) still refuses to find the HD channels. Oddly enough even the TV won't find them now. Any final thoughts before I just pay out for an aerial guy to come in??

Cheers.

[Tev]

Hi Pete

Just a quick thought. You have said you are receiving your TV from the Salisbury transmitter. I believe that the HD mux is transmitted on UHF channel 47. This is very close to channel 49 onwards which are now used for 4/5G mobile phone transmissions, and which can interfere with TV signals. Check your postcode with restoretv.uk to see if any transmitters have gone live in your vicinity, as you may need a 4/5G filter?

Terry

[PeteCarpenter]

Hi Terry,

That's a new line of thought, thanks! Didn't know about that website.

I've just gone through their diagnostic section and ended up emailing them, so I'll keep you posted.

Cheers,

Pete. 

[acecarver]

did you ever sort out the missing HJD channels, i've been having the very same for months and months, BT say top box is ok freeview says theres nothing wrong with the relay and no matter how many times i retune etc nothing changes..........i've followed lots of the helpful replies to you without success.