2017-12-13

Please upgrade me to ADSL over wet string

Unsurprisingly, we had a request, which I am sure was tongue in cheek, to upgrade a customer line to wet string as it seems faster than his quite long ADSL line.

Don't say we don't have a sense of humour at A&A, and no, I did not write this myself :-

Thanks for your interest in our latest technology, ADSL over wet string (fibre broadband)!

Sadly ADSL over wet string is not a product we can commercially offer at this moment in time - partly because it's not a product Openreach sell (or list as selling) to their wholesalers, and partly because, well, it's something we did for giggles as I'm sure you know :)

Looking at the loop loss on your circuit, it's currently running at about 48dB. In our tests with wet string, we attained 56dB on a line length of just 2 meters, which is about the range where the DSL signals starts to fade out.

My very scientific estimate of loop loss using wet string gives about -∞dB loop loss on your estimated line length of 3197 meters, which suggests that providing a wet string service to you is impossible given the losses, you would just not get sync.

Our tests took several attempts to raise sync on a wet string circuit, these timed between 5 and 60 minutes depending on local weather conditions ie. whether the air conditioning was turned on in the office.

I must warn you additionally, that the upkeep of these wet string connections is very hard; in our tests, we had to continually re-wet the string approximately every 30 minutes to avoid a complete loss of sync, and this process was always disruptive to the signals.

Perhaps if there's an exchange within 2 meters of your demarcation point, and if it's ever commercially offered as a product by the wholesale providers we buy from, it might work, but at this stage, wet string is sadly not a viable product for all involved. I suspect it may be expensive too - as there will need to be an engineer trained in keeping the string damp should the British weather deviate from it's usual damp and rainy grimness present unless it's made a self-service option, but that sounds annoying to be honest.

9 comments:

  1. “-∞dB loop loss” - wow, that’s infinite gain! Where can I get some of this magic string?

    ReplyDelete
    Replies
    1. Interesting point, it is usually called loop loss, but usually measured in -ve dB. So yes, technically not loss. Nice one.

      Delete
    2. You wouldn't want a cable with infinite gain - picovolts of noise at one end would emerge as infinite volts at the other - somewhat uncomfortable!

      Delete
  2. It seems like some experimentation with plant feeders is needed to see if a 'self-watering-wet-string' could be developed

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  3. The solution seems obvious. Mount the string inside a long (and, naturally, water-filled) garden hose. This has the added benefits of shielding the conductor (although I doubt it would pass the backhoe test) as well as providing a convenient demarc (garden tap). Any string faults within the property to be the customer’s problem, although you could start a nice racket with a Special Plumbing Investigation “service”.

    There may be unfortunate seasonal DoS issues during hosepipe bans.

    ReplyDelete
    Replies
    1. Heavy rain could cause issues if there are string joints all together in a box. You'd get connected to everyone whenever it rained. Some kind of broadcast storm.

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  4. @Peter I'd imagine the water in the garden hose would be sufficent without the string depending on the mineral content.

    Is that the next experiment?

    ReplyDelete
  5. You need to add more salt into the water...

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  6. You need to add salt into the water to make it slippier to electrons....

    ReplyDelete

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