chorus wiring

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mercutio

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#120904 17-Jun-2013 23:08

so i was wondering if it's normal practice to have huge long redundant cables loop around a few times when installing phone lines. my one is like that, and i know someone else who seemed to experience the same. (although mine is external his is internal)

i know using an extension cable can easily knock a megabit off sync rate, as i've tried with and without before. but will the cabling they use have the same effect? and will the cable be shielded from external radio frequencies?

to me it seems a bit bizzare that they don't just measure and run the cable to length. with maybe a little slack, but multiple loops seems excessive.

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#838423 17-Jun-2013 23:25

New decent quality cabling shouldn't have quite the same effect as a low quality extension cable however ofcourse avoiding extra where possible is always recommended.

michaelmurfy

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#838428 17-Jun-2013 23:46

It's more the wiring in your house you need to be worried about since excessive internal wiring generates a bridged tap, meaning broadband signal is echoed all over the line causing your broadband speed and reliability to degrade.

Long story cut short, the loop on the street is also very high quality wire designed to stop crosstalk and general interference, the wiring in your house is lower quality most of the time - have you also got a master filter?

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mercutio

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#838429 17-Jun-2013 23:50

michaelmurfy: It's more the wiring in your house you need to be worried about since excessive internal wiring generates a bridged tap, meaning broadband signal is echoed all over the line causing your broadband speed and reliability to degrade.

Long story cut short, the loop on the street is also very high quality wire designed to stop crosstalk and general interference, the wiring in your house is lower quality most of the time - have you also got a master filter?

single jackpoint, installed reasonably recently by chorus.

no master filter, i was just doing some reading, and apparently filters can do something about some AM frequencies, and some modems are meant to handle better than others.

it's only cos i was playing with dmt tool, and noticed there are quite a few notches...

also curiously the highest two frequency bins aren't being used. (there are 512, and 510 and 511 arean't being used, it starts at 0 .. )

in general i'm more concerned about external wiring than internal. as it seems lower sync rates are common around here.

i'm not sure if the wiring on the street is actually good quality. it's very thin.

oh for internal wiring, it comes straight in from outside to a face plate. so i'm not actually sure if a splitter would fit in there or what. if doing a splitter, i'd probably want to do it myself, rather than pay someone $200 to do it...

Bung

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#838430 17-Jun-2013 23:52

" huge long redundant excessive." Just how much extra do you think there is? Whatever it is it works better than a cable that's too short.

What is the sync rate so we can see if a little bit extra would make a noticeable difference?

mercutio

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#838432 17-Jun-2013 23:54

Bung: " huge long redundant excessive." Just how much extra do you think there is? Whatever it is it works better than a cable that's too short.

probably only 5 metres, it's in a loop. i dunno if it'd work better going back and forth on top of itself. i didn't really think about it much at the time. i was just looking at the notches in my bitloading graph, and figuring it's am inteference, and that that it may be from the cable... there's probably only 12 notches though.

michaelmurfy

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#838433 17-Jun-2013 23:55

mercutio:

single jackpoint, installed reasonably recently by chorus.

no master filter, i was just doing some reading, and apparently filters can do something about some AM frequencies, and some modems are meant to handle better than others.

it's only cos i was playing with dmt tool, and noticed there are quite a few notches...

Yeah you don't need to worry too much about a master filter, also do not mess with your SNR if that's what you're doing, sure this can boost your sync rate a bit but also causes your broadband to become more and more unstable, it's not worth it.

If you're a Telecom customer feel free to DM me your landline number and I can run a line check.

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Bung

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#838434 18-Jun-2013 00:00

5m is it bit generous. One of my neighbours has something similar. The pole on the other side of the street is getting pulled to one side and when the slack is all gone a bit more is let out.

mercutio

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#838445 18-Jun-2013 00:08

Bung: 5m is it bit generous. One of my neighbours has something similar. The pole on the other side of the street is getting pulled to one side and when the slack is all gone a bit more is let out.

i should not that i'm pretty sure the cable is underground. there's at least underground fibre (but not a ufb zone) and there's overhead power. and there's an overhead line to the house. and it's from the house to the jack point that has the slack in it. i suppose it may be possible to pull it inside and reterminate it if doing a splitter.

i don't actually have any kind of stability problem, i just have highish attenuation and lowish sync for distance from exchange. and the notches look like am, and if phone is underground i thought shouldn't get the notches..

i suppose the ideal solution would be to replace the outside cable with outdoor cat6e, and install a splitter somewhere outside and somehow weather proof it. as it's in auckland it rains a lot :)

Bung

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#838448 18-Jun-2013 00:23

I wouldn't worry about the drop lead from the pole. Your pair ends up in a cable full of other pairs that all have some effect on each other. ISP available bandwidth shared by other customers will be the limiting factor unless your sync rates are really low.

Zeon

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#838467 18-Jun-2013 07:14

Bung: Whatever it is it works better than a cable that's too short.

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chevrolux

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#838475 18-Jun-2013 08:11

Where is the excess loop?

It is generally good practice for any electrical cable to have a bit of slack in it. If it needs to be re-terminated at some point then you would be screwed without a bit of slack. Maybe you are talking about the loop on a pole?

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mercutio

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#838546 18-Jun-2013 09:58

chevrolux: Where is the excess loop?

It is generally good practice for any electrical cable to have a bit of slack in it. If it needs to be re-terminated at some point then you would be screwed without a bit of slack. Maybe you are talking about the loop on a pole?

on the roof

mercutio

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#838597 18-Jun-2013 11:23

gaps are:

Gap1 543kHz-548kHz (Tone126)
Gap2 651kHz-656kHz (Tone151)
Gap3 707kHz-712kHz (Tone164)
Gap4 923kHz-927kHz (Tone214)
Gap5 1082kHz-1087kHz (Tone251)
Gap6 1117kHz-1121kHz (Tone259)
Gap7 1264kHz-1268kHz (Tone293)
Gap8 1324kHz-1333kHz (Tone307-Tone308)
Gap9 1346kHz-1350kHz (Tone312)
Gap10 1440kHz-1445kHz (Tone334)
Gap11 1449kHz-1453kHz (Tone336)

So 12 tones in total not there.

webwat

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#839750 19-Jun-2013 19:30

You still havent told us what sync rate you are getting.... if it s a bit low then the top tones won't be used because they have the highest attenuation. Lower tones have the highest crosstalk, so there might be settings that limit different tones as part of the Chorus spectrum management.

5m slack is not huge; you won't even notice a change in sync rate on a 1km or 2km line. Ancient thin copper to the exchange? If theres still any around then yes it certainly has an effect but the drop cable won't make any difference to that. But if you mess with Telecom's drop cable then you become liable for it. Cat5e isn't tough enough to use as a drop cable.

Time to find a new industry!

mercutio

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#839773 19-Jun-2013 19:51

webwat: You still havent told us what sync rate you are getting.... if it s a bit low then the top tones won't be used because they have the highest attenuation. Lower tones have the highest crosstalk, so there might be settings that limit different tones as part of the Chorus spectrum management.

5m slack is not huge; you won't even notice a change in sync rate on a 1km or 2km line. Ancient thin copper to the exchange? If theres still any around then yes it certainly has an effect but the drop cable won't make any difference to that. But if you mess with Telecom's drop cable then you become liable for it. Cat5e isn't tough enough to use as a drop cable.

just under 15 megabit sync, single jackpoint, 550 metres from cabinet, on same side of rd, and same road as cabinet. closest side street is 650 metres further up the road.

it may or may not be coming up the road and back again. The top tones do indeed have less signal, 28db versus 50db. but there's a few tones with 0db. The lowest is tone 40 with 22db. i think multiple by 4.3 to get khz.

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