Change in linestats after Smarthub firmware update.

[#1]

My BT Smarthub 6 (business version) updated to firmware version SG4B1B009313 on 22 May, and although I can't be certain it happened simultaneously, the line attenuation is now reported as 48.9dB/64.8dB (signal attenuation 46.6dB/65.9dB.)

Although I don't have the exact figures from before the update, I'm pretty sure those numbers are nearly double what they were before, and if correct, suggest that 1) I have moved further from the cab (I haven't!), or 2) the cab has moved further away from me (who knows?). 

If they are indeed correct, my VDSL connection could be in for some big stability issues, although after some recent problems which OR appear to have fixed, the connection itself continues to perform well, with no signs of anything to worry about in the other stats.

Obviously I'm hoping this is a firmware glitch - has anyone else noticed this after the firmware update?

[#2]

@JayG 

Try restarting the Smarthub in case this is a simple glitch.

[#3]

Thanks @Baldrick1  (assumed the hub rebooted itself after the firmware update, but have just restarted it via the interface anyway.)

No major change to attenuation stats unfortunately, although other connection stats good (in fact, U/S best since recent OR intervention, D/S bang up against the stops for my product.)

[#4]

@JayG 

To be a bit geeky: Broadband attenuation reported on a hub is funny stuff. You cannot assume that it is directly proportional to the distance from your cabinet. Whilst the line resistance is a factor that is taken into consideration it also includes the attenuation due to the line reactance and capacitance. As broadband, by its very name, is made up of multiple frequencies over a wide frequency range all that the hub can do is average these out and use that, combined with the line resistance, to report your attenuation.

Now for my theory.  If the firmware change or the reboot increases the hub sync rate then more than likely it will have pulled in more of the higher frequency tones. Generally, these will be attenuated more than the lower frequency ones. Therefore, the average will be higher. If you are not using all these tones, due for example that you are on the 40/10 service, then these lower amplitude tones will be disgarded.

See also: https://wiki.kitz.co.uk/index.php/Attenuation_in_DSL_connections

In summary: Don’t fight it and enjoy your increased bandwidth.

[#5]

Thanks for that @Baldrick1  - I was just about able to follow your explanation and theory.  😉

Although restarting the hub today did improve the connection rate, the changes were minimal (40Mbps v 39.99Mbps down, 7.01Mbps v 6.70Mbps up,)

Although I am of course happy that the connection is running well at present, I've always been blessed (i.e. cursed!) with a curiosity as to how things work (or don't work.)

Might try substituting my other Smarthub to see what it reports (even if it too updates its firmware, I'm assuming it will be a different version as it's not the business model.) Will leave that until tomorrow (mustn't risk upsetting the DLM! 😫)

[#6]

Just for the record, I did try substituting my business smart hub 6 with my 'standard' spare smart hub 6, which reported a line attenuation of '20.3dB', the signal attenuation field was blank.

Put the business smart hub 6 back after factory resetting it - it still reports the very high attenuation figures I mentioned in my first post, but connection still performing well.

Time for some gardening methinks! 😉