Can a TV signal be too strong?

TVEye

Active Member
My TV is a Samsung Q90T, although I think this question applies generally. My signal goes first through my Humax 2000T recorder before going into my TV. The signal is strong, yet I frequently get momentary picture break-up, with the message for no or weak signal flashing up for a split second.
Without wishing to embarrass myself by using the wrong technical terms, I believe I'm correct in saying that the signal will vary between different multiplexes, with BBC1 HD being the strongest, but in the case of a genuinely weak signal, BBC News HD always being the first to go. I had the local aerial guy round to attend to this and after re-aligning the aerial and adding a signal booster, he jokingly assured me that I'd probably now be able to pick up signals from Norway.
As I'm still getting the same problems, is it possible for a signal to be too strong? I'm assuming that I get the weak signal message because they never thought one to tell you the opposite would be needed and that's the only error message available to display.
BBC1 HD is showing Strength 100% and Quality 100%
BBC News HD is showing Strength 87% and Quality 100%
I never try to record from the news channel, so wouldn't know if the channels coming in via that route all work okay – I think they're all rubbish channels that I never watch. Does anybody know of an easy way to deliberately weaken the signal to see if it stops the problem?
 

Rodders53

Distinguished Member
Yes. But less common than one would think.
Your approx, but close, location and transmitter? Will allow estimation of signal levels available.

Professional Aerial Installers should talk in terms of signal strength via meters scaled in deciBels dB referenced to 1 microVolt uV usually. What did he measure at the aerial and at the TV outlets?
What aerial is being used?
What amplifier (aka booster) did he add (and why)? How many outlets are being fed from the one aerial?

NB The recommended level is between 45 and 65 dBuV at the TV outlets.

TVs and PVR meters are a variable feast and use random scales, so it is often difficult to compare one with another.

Humax boxes tend to be sensitive and sometimes dislike signals much over 85% or below 60%. Samsung TVs I have no idea. Where did you make those measurements?

Com7 transmitted power is often 6dB down on the main Psb channels, but that is well within most receivers capability with auto gain control. But com7 moved out with some aerials capability, so became pretty unusable without new aerials.
 

TVEye

Active Member
Here's a variable attenuator you could try..... or you could take out the signal booster that was installed.

Amazon product

Strangely, it won't work at all without the signal booster. It's an Antiference model with just single in and out ports. I can't see the image you appear to have posted.
 

Rodders53

Distinguished Member
Strangely, it won't work at all without the signal booster. It's an Antiference model with just single in and out ports. I can't see the image you appear to have posted.
That will be the indoor power supply to an outdoor masthead amplifier.
Check your receipts for make and model number or call the installer for that information, or we can't advise as accurately as without that info.

You could enable the antenna power option of the Humax to drive the masthead amp (having disconnected the Antiference unit first).
 

TVEye

Active Member
Yes. But less common than one would think.
Your approx, but close, location and transmitter? Will allow estimation of signal levels available.

Professional Aerial Installers should talk in terms of signal strength via meters scaled in deciBels dB referenced to 1 microVolt uV usually. What did he measure at the aerial and at the TV outlets?
What aerial is being used?
What amplifier (aka booster) did he add (and why)? How many outlets are being fed from the one aerial?

NB The recommended level is between 45 and 65 dBuV at the TV outlets.

TVs and PVR meters are a variable feast and use random scales, so it is often difficult to compare one with another.

Humax boxes tend to be sensitive and sometimes dislike signals much over 85% or below 60%. Samsung TVs I have no idea. Where did you make those measurements?

Com7 transmitted power is often 6dB down on the main Psb channels, but that is well within most receivers capability with auto gain control. But com7 moved out with some aerials capability, so became pretty unusable without new aerials.
He added the booster because I wanted to use an extra TV in the conservatory. It is of a type that's added inline where the coax lead comes out of the wall, and not one that goes on the aerial. The wiring had been installed by the previous house owner but it wasn't satisfactory. The measurements are accessible from the Humax menu and show up as a signal strength indicator for every channel, even the ones which are at zero, or too marginal to receive a picture. It isn't quite a continual problem, but one which varies either according to the weather, or perhaps due to transmitter works that we never get to hear about.
 

Rodders53

Distinguished Member
Transmitter works are not permitted to reduce power significantly for the BBC at least.
Duplicated: transmitters, signal feeds, code and mux centres. Transmit antennas have main on top and reserve lower, but the emitted power is the same.
Rarely switching breaks could cause signal disruptions.

More likely is local issues trees, wet windy, signal fading as a result.

Answer the Questions above re location for signal levels.
Model of the one way amp (gain and noise figs) and how is the signal split to feed two? with what?
 

Rodders53

Distinguished Member
Dena Vu?

 

TVEye

Active Member
You could enable the antenna power option of the Humax to drive the masthead amp (having disconnected the Antiference unit first).
That's interesting because I always assumed that the 'antenna power option' was something to do with some kind of special aerial - possibly one with a motor fitted to enable it to be swivelled.

I couldn't remember if I'd already posted about this on here, or whether it was another forum. I tried a search on the topic which yielded no results.
 

The latest video from AVForums

Maverick UK Premiere IMAX Review + Top Gun, Tom Cruise, Tony Scott and 4K + Movie/TV News
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom