Old Drop Wire And SNR

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My question is, if this drop wire were (somehow!) replaced by BT with a new twisted pair cable, is this likely to improve my SNR?

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I very much doubt it. Your old dropwire 3, as it is known, is as you say not a twisted pair, but on the plus side the conductor size is much greater than the new stuff.

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would replacing the final 10-15 metres of cable in a 3.7KM run make no noticeable difference?

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You got it.

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Does anyone know if these old drop wires can be troublesome to ADSL

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No more than any other.

Sounds like you've done all the right things - I heard that BT will put your overhead wire underground for free - if you dig the trench and lay the duct for it !

The only other thing I can suggest is that you might gain a little by changing the router to one where you can adjust the target SNR with the DMT utility from dmt.mhilfe.de (I'm not sure whether the Belkin can be used with this). I have a Speedtouch 546 (two in fact, see my sig), and these will reliably sync down to 3dB. Even after the 10-day training, your profile will still follow the modem sync speeds. I have to say that 3.5M isn't bad for a 50'ish attenuation, so you are clutching at straws a little, and if you do buy another router, it may not make any difference at all.

Edited by deleted (Sat 28-Oct-06 13:04:33)

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I heard that BT will put your overhead wire underground for free - if you dig the trench and lay the duct for it

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Not true.

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Sounds like you've done all the right things - I heard that BT will put your overhead wire underground for free - if you dig the trench and lay the duct for it !

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This would mean digging up the driveway, a bit of a drastic (and expensive!) thing to do incase it MIGHT mean I got an extra half a meg download speed. I'd stick with what I've got unless replacing the overhead cable might improve things.

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The only other thing I can suggest is that you might gain a little by changing the router to one where you can adjust the target SNR with the DMT utility

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That looks like a useful utility, but it says it's for Thompson products, so I don't know whether it would work with Belkin? I've already recently replaced the router. Originally (when I was on 2 MB fixed speeds) I had the older Belkin 7630, which occasionally lost sync and could be a pain to get re-connected. I replaced it with the 7633 which is much more stable, but the SNR seems to fluctuate a lot more...

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I have to say that 3.5M isn't bad for a 50'ish attenuation, so you are clutching at straws a little, and if you do buy another router, it may not make any difference at all.

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I don't think it's worth replacing the router for the time being, especially as I only spent

not clear on the question, a 2272 sync (ATM rate) gets a 2M profile (TCP/IP rate) which speedtests at about 1880 kbits/s of data. 8128 = 7.15M = 6700 kbits/s on same basis.

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I very much doubt it. Your old dropwire 3, as it is known, is as you say not a twisted pair, but on the plus side the conductor size is much greater than the new stuff.

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I'd noticed the conductors were much thicker than the new cable, so would offer less resistance, I was just a bit concerned that not been twisted pair, it might be more prone to picking things up like AM radio and interference from the nearby streetlight more?

BT have recently replaced all the telegraph poles on our street recently for some reason, except for ours, which appears to have a split down the middle (!!!) So what I was hoping for is if they do get round to replacing ours in the near future, they'll also replace the dropwire...

If that happens and it does improve my stats enough for a stable 4MB, I'll be very happy! But if it makes no difference and I'm stuck with 3.5MB, then I'll be satisfied with what I've got. It's still 7 times faster than my first 512K broadband connection, and almost 90 times faster than the connection I had on dialup!

Tim

there is a DMT version for the Belkin

# DMT v8.04
Speedport 500V/W500V, Siemens SLI-5300-I/SL2-141-I, Speedtouch 716g, Belkin 7633,
T-Sinus 1054 DSL, BT Voyager 2091/2100/2110, Linksys WAG54GS, USRobotics 9107/9108,
Netgear DG834GT/DG834PNB, Hitachi AH4222, (BCM6348 adslctl)

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not clear on the question, a 2272 sync (ATM rate) gets a 2M profile (TCP/IP rate) which speedtests at about 1880 kbits/s of data. 8128 = 7.15M = 6700 kbits/s on same basis.

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For fixed rate speeds such as 2MB, they, as you say, give you a sync rate of 2272 (2.2MB) which gives you a 2MB profile/throughput after ATM overheads. So the actual throughput speed you get is the same 2MB as what the product is advertised at.

For 8MB max on a good line, you get an 8128 sync (8.1MB) but after taking into account the overheads, you can only get a maximum throughput of 7.15MB, not the advertised 8MB.

My question is, according to BT's "guestimator" my line should support a max speed of "4MB or greater". Does this refer to a 4MB sync speed ie 4000, which would give me a 3.5MB profile, or a 4MB profile/throughput speed, for which I'd need a sync of 4544?

I'm guessing it means a 4MB sync speed and 3.5MB profile/throughput, because if I put in a number closer to the exchange into the checker it says a max speed of 5.5 - 8MB should be possible, and I know that the 8MB has to refer to sync speed and not throughput!

I know the BT checker is only an estimate, and either way it makes no difference to my end result, I was just wondering because BT don't make it clear exactly what the 4MB it thinks my line can handle means? 4000kbps sync, or 4544kbps sync?

Tim

the checker talks about ATM rate = sync rate.

The "8M" marketing claims started with UKonline and Bulldog followed.