Samsung TV - Poor Signal Reception

[Ian400]

My Samsung TV with PVR connected has severe pixielation problems and sometimes makes noises that seem like 'Spitting sounds. I disconnected the PVR leaving the TV directly connected to the aerial. The interference is lessened but still there.
I looked through the TV menu and found that the signal strength for BBC1 and BBC2 is good at 68 to 84. But on ITV and Channel 4 is much less, about 24 to 40 with Bit Error Levels showing. This is with the PVR disconnected.
I have replaced all the aerial cable from TV to roof aerial. Also tried changing the direction of the aerial, to no avail.
I am in the London area, signals from the Crystal Palace transmitter. I noticed that on the TV menu BBC1 & 2 use Multiplex 23C, ITV & Ch4 use Multiplex 26C.
I would appreciate any advice on sorting this out.
Thanks Ian

 

[Lucid]

Crystal Palace is the UKs most powerful transmitter, but at the moment there's no info about your location, the aerial (its type and orientation) or if your aerial is inside/outside/blocked by trees or buildings... so all this leaves far too many options to start shooting in the dark.

The other observation from what you've written is that all the channel muxes are at the lower end of the channel spectrum. They range from Ch22 to Ch35. If you have a "High Gain, Wide Band" aerial then this could be part of your problem. They're not very efficient in the channel range where Crystal Palace broadcasts. The "High Gain" bit is at the upper end of the frequency range where it's useless for you. Have a read here about Log Periodic aerials. They're popping up all over the place on houses for lots of good reasons. Log Periodic

You might also want to check out the Wolfbane site. Their signal predictor is a rough and ready tool for gauging approximate signal strength. It can't predict for when an aerial is blocked by buildings or trees, but it's still a useful tool. Wolfbane

Signal strength really should play second fiddle to signal quality. That's far more important.

 

[amjmfareham]

Crystal Palace is the UKs most powerful transmitter

Yes, Crystal Palace may be one of the most powerful transmitters in the country, but there are others in the country that are as equally powerful, with the other ones being Rowridge on the Isle of Wight (My Transmitter) and Sutton Coldfield in the West Midlands, all operating at the same power output.

This site, with the URL below, contains a wealth of information on aerials and some of the main transmission sites in the United Kingdom!

http://www.aerialsandtv.com/nationwidetransmitters.html#TransmitterTopTwentyPower

 

[ellal]

I have a similar problem with a Samsung TV that I haven't been able to solve, although it is the BBC SD channels that I have trouble with.

We have 4 TV's in the house.

I have tried all location variations, and three of them work perfectly in all 4 locations whilst the Samsung has the same problem everywhere.

I hooked up an old Humax HD-Fox T2 Receiver to the TV and it worked fine too.

So I can only assume in my case at least that it is the TV that has a signal strength/quality problem, but of course I can get nothing out of Samsung!

 

[Lucid]

I have a similar problem with a Samsung TV that I haven't been able to solve, although it is the BBC SD channels that I have trouble with.

........

So I can only assume in my case at least that it is the TV that has a signal strength/quality problem, but of course I can get nothing out of Samsung!

TV tuners range in sensitivity within an allowable range, so you might find one TV has better or worse reception than another. However, all should give a picture so long as the aerial signal is also within acceptable limits.

Problems tend to arise if the tuner or TV aerial socket is broken, or if the aerial system has issues such as being split too many times or over amplified. Where the aerial on the roof and its down lead are in good working order and appropriate for the area, then in cases such as yours excessive splitting and over amplification are possibly the most common causes of problems.

From your description I'd say there's another clue too. You're having problems with the BBC SD channels. These are part of the core range of channels that most households should be able to receive as part of the Public Service Broadcasting (PSB) remit. They are broadcast in the transmitters higher power muxes. In short, these are the signals you should be able to receive in all but the worst conditions.

In the absence of other information, the fact that the Samsung picks up the lower power channels (I presume) without issue points to there being too much signal via your aerial system rather than too little. The signal for that mux could be swamping the tuner. This will result in problems that look very similar to low signal quality on digital, and it often goes misdiagnosed as exactly that.

The answer in most cases is to fit an attenuator to reduce the signal level for that particular TV. It's a very useful and very inexpensive diagnosis tool. This one is useful because there's a level control on it to allow the signal level to be adjusted: MA1620 Adjustable 0-20dB attenuator, coaxial connector version

When making the adjustment, use the TV's Signal Quality bar when tuned to the BBC SD channels as a guide. When there's too little or too much signal this will go down. When the level is getting towards the correct range then the bar will show higher quality. Stop adjusting when the bar indicates the highest quality. Check the other stations to make sure you still have good reception there too.

Let us know how you get on.

 

[ellal]

The answer in most cases is to fit an attenuator to reduce the signal level for that particular TV. It's a very useful and very inexpensive diagnosis tool. This one is useful because there's a level control on it to allow the signal level to be adjusted: MA1620 Adjustable 0-20dB attenuator, coaxial connector version

Just picked up a similar attenuator from our local electronics 'bits and bobs' shop, and after playing around for a bit the missing/dropping out BBC1/2/News SD channels are back!

I need to wait until this evening to check BBC3/4, but I'm sure they will be OK too.

Many thanks Lucid...

Edit: As expected/hoped all BBC SD channels working