planiwa
join:2009-02-19
Toronto M5S
3 edits |  Do you *know* your Wire-Length from the C.O.?
If you do, perhaps you would like to contribute to a research effort that will benefit the users of these forums?
By know I mean that you have been told by a phone-company technician what your wire-length actually *is*.
I am looking for data samples in order to tune and validate models of the relationship between Signal Attenuation and Wire Length. Perhaps you would like to help by contributing your parameters?
I am looking for data points consisting of three items:
1. Wire Length. (e.g.: 4.0km)
2. Upstream Attenuation. (e.g.: 27dB)
3. Downstream Attenuation. (e.g.: 46dB)
Additionally you may wish to include:
4. The source of your Wire Length data. (E.g: Bell technician).
5. Your approximate location (Postal Code Prefix, e.g.: M5S).
6. Any other relevant information that you may wish to share about the line, such as sync rate, SNR, Line Capacity, xDSLy, etc. (E.g.: did technician look it up from wire-length data base or back-calculate it from attenuation?)
I will post the aggregate data chart and analysis when I get over 30 data points.
You may wish to post your contribution, or you may prefer to send an Instant Message.
Thanks for your help. |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0
 ·Rogers Hi-Speed
Host:
Rogers
Bell Canada
| The data you're collecting will probably be corrupted by the fact that most techs will determine the wirelength by a formula applied to a loopback condition, or by road distance to the CO.
Knowledge of the actual physical wire length is as rare as hens' teeth and rocking horse droppings. |
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JimmyArms
join:2008-01-09
Sault Ste Marie, ON
1 edit | reply to planiwa
I'm on a remote.
Wire Length: approx 100 meters..source: bell tech pointed at it out my front door
Upstream Attenuation: 15.0 db
Downstream Attenuation: 25.0 db
SNR: 11.0 dB (Downstream) 15.0 dB (Upstream)
Postal Code Prefix: P6C |
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planiwa
join:2009-02-19
Toronto M5S
| Thanks. I wonder whether that might be one of those semi-fixed IKNS Remotes. The Attenuation values seem to be 5-10 times what might be expected, and reversed. But, all data is of value, if only to illustrate variability.
(I have one site 100m from (IKNS) Remote.)
Atn US Atn DS
20.5 17 before
5.5 5 after June 29th
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JimmyArms
join:2008-01-09
Sault Ste Marie, ON
 ·TekSavvy Solutions..
1 edit | reply to planiwa
Not IKNS
and damn I did reverse them
my DS Atn was about 19 or 20. it shot up after a recent rain storm
might also have to do with the fact that I bought a 100' phone line extension from a bargain shop and cut off the end to hook-up at the demarc and ran that to my modem lol |
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planiwa
join:2009-02-19
Toronto M5S
| So, did you also get readings at the Demarc?
I would expect your Demarc Attenuation readings to be something like:
US: 1 DS: 2
And the 100' tinsel extension to add
+14 +23
But it would be good to have confirmation of that.
As it stands, your Attenuation values indicate a wire length of 2,200m, not 200m. |
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JimmyArms
join:2008-01-09
Sault Ste Marie, ON
·TekSavvy Solutions..
1 edit | No, no readings from the demarc, but the bell tech did point out the remote to me because it was new and they only installed it about a month before.
I'd asked because I assume I was on one about a mile and a half away but he told me they had just put two new ones right by my house, the one I'm on is probably less than 100 meters. I could probably throw a rock and hit it from my front lawn. The other one is about 3 - 400 meters in the opposite direction.
I'm right between two sub-divisions.
And to answer some of your other questions, I'm on
Downstream Rate:7040 kbps
Upstream Rate:800 kbps
Channel:Fast
and the bell tech said I could easily do 8MB
Considering I'm about 500 miles north west of Southern Ontario, that's pretty good. |
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planiwa
join:2009-02-19
Toronto M5S
| Thanks for you contribution, even though I can't use it, since the Attenuation readings are clearly severely contaminated by your 100' tinsel.
It's now been more than 24 hours and there has not been a single usable data point. That, in itself is information.
It seems that many people are quick to say: "You are very far from the CO!", or to ask "How far am I from the CO?", yet no one seems to know for sure what they are talking about.
Or if they do, they don't want to talk about it here.
--
"Cool Locally -- Warm Globally." |
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dslrocker3
join:2002-05-26
Toronto
2 edits | reply to planiwa
for me:
4.3KM (told to me by High Speed Centre)
current ds attenuation 58 dB
upstream 31.5 dB
May I suggest not be so quick to dismiss any data for any reason? Data is data and excluding any of it for any reason can scew your results. Thinking that a peice of data is not usable and excluding it can cause the researcherc to only accept information that they already consider to be the norm which can cause them to make conclusions that they were already expecting or were hoping for. Data over a large sample gets averaged out regardless and all information provided should be used. Results are always up to interpretation and that is where you should be using your judgement to theorize/make conclusions. |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0
·Rogers Hi-Speed
Host:
Rogers
Bell Canada
1 edit | The distance measurements people get from the CO are not always what Plainwa is seeking ...
He is looking for the physical cable distance.
What most of us get as "distance from the CO" is one of the following ...
.distance the crow flies
.distance along the most direct likely streets to the CO
.calculated distance based on direct current loopback results
.calculated distance based on MF (multi frequency) loopback results
.calculated distance based on DSL modem attenuation figures (which isn't a lot of use considering that's what he's trying to calculate)
All of these would make his attempts to build a new model for a formula totally useless.
The biggest problem is the path your cable takes is not always the obvious route. Take the scenario of multiple parallel streets. You'd think the obvious route would be to go all the same direction to the end of the street closest to the CO, but the reality is that the cable might snake back and forth up one side of a street, down the other, up and down the next street etc. etc. So while you may be 200 metres from the CO, the cable may go 2 km!
The other problem is that your cable may not go to the obvious CO. This happens most commonly when homes are built at different times, or there's some geographic / geologic barrier between you and the CO. |
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dslrocker3
join:2002-05-26
Toronto
1 edit | said by sbrook  :The distance measurements people get from the CO are not always what Plainwa is seeking ... He is looking for the physical cable distance. I am wondering how anyone would know the actual physical distance length, short of getting a really long measuring tape -which just isn't going to happen. Besides, any number provided, even if Bell was willing to provide this information, would just be approximate, would it not? Also, these approximations are already provided by things that you just mentioned (by attenuation, results from electronic testing,etc.). I just don't see how getting a physical length would even be doable. I believe that the approximations are done because the real distance is next to impossible to attain. |
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planiwa
join:2009-02-19
Toronto M5S
| reply to dslrocker3
Thank you for your data contribution. I would appreciate knowing your Line capacity Estimate (from modem or lantern), since one of those two measurements appears to be truncated by the modem.
Thanks for your advice.  |
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dslrocker3
join:2002-05-26
Toronto |
synced at 2496@91%/800@95% |
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planiwa
join:2009-02-19
Toronto M5S
| reply to JimmyArms
said by JimmyArms :No, no readings from the demarc Thanks again for your contribution. If you should ever be able to get a reading from the Demarc, I would very much appreciate it, since it would be valuable to know how 100' of spun-tinsel phone cord affects Attenuation. |
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planiwa
join:2009-02-19
Toronto M5S
|  reply to dslrocker3
Thus far there have been two contributions:
## Leng AtnU AtnD CapU CapD SNRMU SNRMD PCP Name Comments ...
01 100 15.0 25.0 ? ? 15.0 11.0 P6C JimmyArms (Remote pointed at)
02 4300 31.5 58.0 842 2743 ? ? ??? dslrocker3 (told by HSC)
Extended comments:
01 (100' flat cheap phone cord) syncrate: 800/7040 FP
-- From the Original Request: "I mean that you have been told by a phone-company technician what your wire-length actually *is*." |
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