Before we begin this discussion, it’s important to note that all televisions and television services are different. Not everybody will be able to find a reading on their signal’s strength or quality, and some will only see arbitrary numbers or percentages that seem to have no meaning. Still, regardless of what is displayed, it is still helpful to know what this information means for your signal.
This is Just a Guide
Televisions Don’t Provide Enough Information
Having 100% Signal Isn’t That Important
The Real Focus Should Be On Quality
There is No Real “Standard” for How Signals Are Read
Correctly Reading TV Signal Strength
For reference, here is a quick guide to the MINIMUM signal strength levels of several types of televisions.
- Terrestrial Digital TV – 50dB
- Analogue TV – 60dB
- Satellite TV – 52dB
Correctly Reading TV Signal Quality
You can measure signal quality in a few different ways:
Signal to Noise Ratio (S/N)
This is the measurement of the peak signal reading and the noise floor of the signal, but ignores noise present in the signal itself.
Carrier to Noise Ratio (C/N)
This measures the signal floor and compares it to the signal being received. It doesn’t measure any noise present in the signal, but it does account for it.
Modulation Error Ration (MER)
Considered the best measurement for digital TV signal reliability; this measures both the signal and the noise present inside of it.
Bit Error Ratio (BER)
There will always be some errors in a digital signal – it’s unavoidable. That is why signals have a built-in error correction known as FEC or Viterbi EC. When you see that 100% reading, you are seeing no errors because correction has already automatically taken place. When there are errors still present after correction, you will see pixelated or blocky images.
The Truth About Amplifiers
If you place the device too close to your television, for instance, you will boost the levels of electrical noise in the signal and introduce new noise to the readings. You also risk overloading the equipment, which is just as bad for the picture as a weak signal.
As a rule of thumb, amplifiers are best used where the signal enters the TV tuner in a weakened state. This should help boost the signal enough to maintain reliable reception.
Conclusion
It’s important to remember – despite all this information – that the signal and quality readings reported by your TV should only serve as a rough guide. As you can see, there is much more that goes into the process, and those who try to make adjustments on their own often do much more harm than good.
When in doubt, contact a professional and have them evaluate your signal, TV, tuner, and / or amplifier with high-quality equipment.
As always, if you have any questions or comments, feel free to send them my way!
Cheers.
Digitec Aerials Preston
The Watermark, 9 – 15 Ribbleton Ln, Preston PR1 5EZ
Tel: 01772 369629
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