topic Re: Shielded ADSL cable - stats before and after in Broadband

Shielded ADSL cable - stats before and after

NatTheGooner — Sun, 18 Dec 2011 17:32:41 GMT

Hi guys.
I swapped my 5m ADSL cable with an £8.99 5m shielded one and I thought I share the stats.
Theres a small speed increase and web-browsing seems very snappy.
The connection gets an A rating on speedtest.net - it used to be B
stats are over about 3 days each...
not sure what all the stats mean, but it might be useful to someone.

Re: Shielded ADSL cable - stats before and after

WelshPaul — Sun, 18 Dec 2011 17:59:21 GMT

You appear to have a lot of errors on your connection.
Here are my error stats over 2 days 8 hours compared to yours...
Since Link time = 2 days 7 hours 40 min 51 sec
FEC: 0 0
CRC: 508 473
ES: 426 286
SES: 0 1
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
~ #
Although changing the cable has made a small difference for you.

Re: Shielded ADSL cable - stats before and after

w23 — Sun, 18 Dec 2011 18:02:50 GMT

That's certainly interesting. Mine made no difference at all (probably just indicates that my previous cable was not too bad). As far as I am aware the shielding will make little difference unless it's actually properly grounded at one end, on the other hand it almost certainly is a decent quality cable with proper twisting of the pairs (after all, the line from your master socket back to the cabinet or exchange is unshielded twisted pair so a little shielding on the very last bit is not so terribly important unless it runs directly past something that creates interference).

Re: Shielded ADSL cable - stats before and after

caulbox — Sun, 18 Dec 2011 18:04:18 GMT

Quote from: NatTheGooner
The connection gets an A rating on speedtest.net - it used to be B

Can you add a link to your speedtest result?

....are you sure the "A" rating isn't from pingtest.net?

Re: Shielded ADSL cable - stats before and after

NatTheGooner — Sun, 18 Dec 2011 18:07:51 GMT

I thought I'd try it because my router is in with all my other tech in a cabinet under the TV.
The ADSL cable ran alongside power cables and 3 Freesat feeds, so lots of potential interference.

Re: Shielded ADSL cable - stats before and after

NatTheGooner — Sun, 18 Dec 2011 18:09:39 GMT

you're right it was ping test.net - sorry
It got a B* for the first 3 days then an A after swapping the cable.

Re: Shielded ADSL cable - stats before and after

Anonymous — Sun, 18 Dec 2011 18:13:50 GMT

The difference between the standard ADSL cables and the supposed higher quality cables is that the cheap versions only have two wires either twisted or untwisted, but the more expensive versions use four wires where the standard two wires are twisted with the additional wires and then those pairs twisted together. I'm not convinced that shielding makes any difference, but I have seen repeatable slightly better speeds using 4-wire RJ11 cables over a similar length of 2-wire.

Re: Shielded ADSL cable - stats before and after

w23 — Sun, 18 Dec 2011 18:16:34 GMT

Quote from: purleigh
either twisted or untwisted

Untwisted wires are definitely more likely to suffer from interference from certain sources.

Re: Shielded ADSL cable - stats before and after

oldgeezer — Sun, 18 Dec 2011 18:25:45 GMT

I have used one of the 10 metre screened ADSL cables, run under the floor before the new carpets went down, as a network cable. It will only work for 100 Mb of course, not enough pairs for Gigabit but it works well. I terminated each end in a CAT5e modular socket which is designed for solid cores 'so I tinned the bared stranded ends and they fitted the IDC's nicely. I can use it to send ethernet from my router by the master socket or send ADSL to the router if sited by the computer. Identical results either way.
Oldgeezer.

Re: Shielded ADSL cable - stats before and after

JayG — Sun, 18 Dec 2011 18:38:42 GMT

I bought a "15m high quality, gold-plated contact, twisted pair RJ11 cable" from Amazon at a price which was so low I'm too embarrassed to mention it here! The idea was to bypass my very old system of telephone extension wiring (including an extension socket) so my telephone and ADSL could be kept completely separate (only one ADSL filter required now, connected directly to the master socket - the phone extensions now all run from the filter telephone socket.)
Maybe a slight improvement in reported attenuation and SNRM, but mainly peace of mind that the BB side of it is now brand new and routed well away from any obvious sources of interference.

Re: Shielded ADSL cable - stats before and after

x47c — Sun, 18 Dec 2011 20:09:41 GMT

The physical cable that runs back to the cabinet from your house's secondary connection point is probably 3ft underground and contains a bundle of other line pairs which will have an outer spiral wrap steel wire armouring round it before an outer PVCsomething sheath.
I'd say its fairly well shielded and earthed....
I would second an earlier comment that shielding needs to have a single dedicated telephone only earth to function properely - multiple earths are even worse.
Biggest problem in some rural properties is the long length of dropwire from the nearest pole to various houses which are strung out - just like an aerial should be in fact and they probably act like one as well.
(? is drop wire twisted pair - one suspects not, possibly a spiral twist to the 4 cores rather than true twisted pair)
There are also some who say you shouldn't run data cables and 240V mains next to each other, probably not a good idea for any great distance, but equally probably not significant in the lengths encountered in domestic properties.
I use Cat5e FTP shielded/earthed cable for all my telephone wiring. Data points round the house from the router are likewise CAT5e terminated in RJ45 outlets.

Re: Shielded ADSL cable - stats before and after

itsme — Sun, 18 Dec 2011 20:16:46 GMT

Quote from: x47c

The physical cable that runs back to the cabinet from your house's secondary connection point is probably 3ft underground and contains a bundle of other line pairs which will have an outer spiral wrap steel wire armouring round it before an outer PVCsomething sheath.
I'd say its fairly well shielded and earthed....

Not sure whether Openreach go to the expense of putting in underground ducting then use armoured cable in it.

Re: Shielded ADSL cable - stats before and after

w23 — Sun, 18 Dec 2011 20:23:03 GMT

Even if the cable is 'armoured' (SWA) the bundle relies entirely on proper twisting of the pairs to minimise crosstalk, if it's 3' underground then there's not too much opportunity for interference (that's NOT to say that REIN interference from external sources isn't an issue for some.

Re: Shielded ADSL cable - stats before and after

x47c — Sun, 18 Dec 2011 21:07:32 GMT

Quote from: itsme

Not sure whether Openreach go to the expense of putting in underground ducting then use armoured cable in it.

Round here the cable from the cabinet back to the exchange IS in ducts, but the cables radiating out from the cabinet along the various roads to properties are all armoured stuff laid direct in the ground (in NOT in ducts)
I agree with you, if in ducts then no need for armouring.
I'm sure I've heard that the main E side cables out from the exchange are actually air cored and pressurised up to a few psi with dry air to prevent moisture getting into them.
By air cored I mean the spaces between the hundreds of pairs of lines in the physical cable is filled with air rather than some plastic/PVC compound.

Re: Shielded ADSL cable - stats before and after

pierre_pierre — Sun, 18 Dec 2011 21:21:29 GMT

my house is about half a km from the cabinet and the cable is definitely ducted to a manhole just outside my house and then further down the road, the pole is a further 10 metre from the manhole, and feeding about seven houses from the top, my synch to a lousy 40 year old junction box is 14M

Re: Shielded ADSL cable - stats before and after

oldgeezer — Mon, 19 Dec 2011 10:21:48 GMT

Quote from: itsme
Quote from: x47c

The physical cable that runs back to the cabinet from your house's secondary connection point is probably 3ft underground and contains a bundle of other line pairs which will have an outer spiral wrap steel wire armouring round it before an outer PVCsomething sheath.
I'd say its fairly well shielded and earthed....

At one of our previous homes the cable that ran from the PCP cabinet to our local pole was buried less than 3 INCHES in the ground. It was also not armoured.
When a former garage site at the top of the road was replaced by a terrace of houses the three services (water, gas &power) were connected seperately as each house progressed.
Every time a new service was connected did we lose our telephone line. You couldn't blame the contractors, the cable was laid in the top (finish) coat of the tarmac. Each time BT laid a pair of GRP boxes in the pavement with a yard of cable between them. By the time the last house was finished there was a neat row of these boxes all down the pavement. At last sanity prevaled and all but the first and last boxes were removed but the linking cable was still laid at the same depth.
Oldgeezer