Digital TV Reception Keeps Scrambling

Where is the 'booster' (ie: is it near the aerial) and how many outputs does it have?

Also how are you feeding the two tv's from other tv's?

It sounds to me like you probably need an 8 way distribution amplifier near to the aerial (something like this: https://www.screwfix.com/p/labgear-lda2081lr-8-way-distribution-amplifier/8855x ) so each tv gets its own feed.

If you've split the feed from the booster to two TV's then you've halved the signal at best. If you've used low quality coax or not done a great job of termination or adccidently one a strand of the braid touching the core it might well be less.
Dissect a TV cable from a poundshop if you want to see what low quality cable masquerading as coax loks like.


And then what others above said about sensitivity.
If the amp has an adjustable gain try turning it up.
But too much gain will also distort the signal as it raises the noise floor above the signal level.

I have a 4 way amp going to a few TV's and also into another 4 way amp.
This has worked fine for a long time but with the recent TV retune we lost one of the channels which moved to the local mux and they lowered the tx power of the local mux. I had to fiddle with the gain a little on both to fix it.
The longer plan is to eliminate the two amps and go with one 12way. 4 TV's in the house, 4 tuner cards in a PC and room for expansion as amp into amp is a crappy solution at best.

I asume you are using an arial to receive terrestrial 'free' digital signals.


As posted above different TVs have different sensitivities, some needing a higher signal level to decode consistently well. Secondly different channels cover sightly different parts of the spectrum. Put those two together and even with no cable etc. faults you can have a variety of results between TVs and channels. With yours it seems that to some TVs the signal is marginal and under marginal signal conditions there can be a dramatic decode quality change. That is a function of it being digital!


It may be that improving signal reception just a little cures it all and that might be your first port of call. As posted by jack, all other things being equal, an outside antenna should not get a signal attenuated by walls compared to one internally loft mounted. You can decide if external mounting is easy to do.
However it sounds like a small improvement could be all that is needed. Small changes in arial position, fore and aft, laterally, vertically, angular (in all planes) of only a few centimetres/degrees can make a big difference.....and that is easy to do by trial and error but posxibly frustratingly slow!. The correct orientation for your transmitter is essential too. You can also look to install an arial with higher gain. As a rule of thumb the more elements the greater the gain and potential for better signal.

htrj wrote: »

Thanks for the replies,

The booster is about 10 ft away from the old aerial. Nothing has been moved and that system worked fine for more than a decade at the very least.

Today it is absolutely lashing down outside..... and two more of the normally working TVs have started scrambling....... inside the loft is dry. Is it known for Coax to go porous?

Unless the coax is outside then the weather won't make any difference I wouldn't have thought. If it's outside, then particularly the cheap stuff can get water in it.

Weather conditions can attenuate the signal.

As can works on the transmitter etc.
https://www.freeview.co.uk/corporate/platform-management/planned-engineering-works

Plenty about the transmitters, known problems etc online if you look.