Negative SNR !!!!!

[kinmel]

It is not often that you get a negative SNR and maintain the sync, but mine has been dipping below zero and just climbing back up above for a while all day long. 

On Adsl2+ it has a nominal 3dB margin and has been hanging in there since Christmas.

[Lance]

The modem must be working right at its limits to maintain the sync.

[Polchraine]

The lowest mine ever went to was -0.7 ... it would often sit down at -0.1 or -0.2 for quite long periods (tens of minutes).

It does show how good the front end of the 2700 actually is.

[Rik]

It's why we love them.

[esh]

If I'm thinking correctly, -0.7dB would mean the noise is actually more significant than the signal by a factor of ~1.2. Something like that anyway.

[Polchraine]

If I'm thinking correctly, -0.7dB would mean the noise is actually more significant than the signal by a factor of ~1.2. Something like that anyway.

Yes - but remember that the noise is measured and averaged across the band as is the power of the signal.   There could be a very noisy part of the spectrum which creates that effect - but it still shows how well the 2700 copes with high noise levels.

There are comms systems where the signal can be 10 or 20 dB below the noise floor - but by careful use of multiple antennas and electronic beam steering (introducing nano delays) it is possible to bring the signal up above the noise.