How on earth did I get VDSL with this kind of attenuation?

Forums › Spark New Zealand (including Skinny and BigPipe) › How on earth did I get VDSL with this kind of attenuation?

misha256

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#157342 27-Nov-2014 23:17

Hi everyone,

I got my Spark VDSL connection today. Attenuation down is 23.6dB. I thought Spark had a target of 10.8dB and wouldn't even let you near VDSL if your attenuation was going to be much higher than that.

That's got me thinking. I'm about 900m from the cabinet. Is 24dB normal for this distance? If so, why did Spark allow a connection that well exceeds the target?

Not complaining though. I'm getting 20% faster down and 8x faster up (compared to ADSL2+ I had before). Modest bump, but very handy for those large uploads to the cloud. Still, I'm quietly hoping someone will say "you should be seeing ~10dB even at 900m"

Modem stats:
ASUS DSL-AC68U (3.0.0.4.376_2072)
DSL Firmware Version      1.0.1.7
DSL Driver Version      FwVer:5.5.1.124_A_A60901 HwVer:T14.F7_0.1
DSL Link Status      up
DSL Uptime      0 days 3 hours 7 minutes 57 seconds
DSL modulation      ITU G.993.2(VDSL2)
Annex mode      ANNEX_A
SNR Down      11.8 dB
SNR Up      12.3 dB
Line Attenuation Down      23.6 dB
Line Attenuation Up      49.1 dB
Data Rate Down      18902 kbps
Data Rate Up      6687 kbps
MAX Rate Down      23056
MAX Rate Up      7101
POWER Down      18.6 dbm
POWER Up      8.6 dbm
CRC Down      2
CRC Up      0

Speedtest before upgrade (on ADSL2+)
Speedtest before upgrade (ADSL2+)

Speedtest after upgrade (on VDSL2)
Speedtest after upgrade (VDSL2)

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#1184533 27-Nov-2014 23:17

Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

If you are posting regarding DSL speeds please check that

- you have reset your modem and router

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

- you are not being throttled by your ISP due to going over the monthly cap

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

- you read this topic and follow the instructions there.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

- Your ISP and plan

- Type of connection (ADSL, ADSL2, VDSL)

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

- Your general location (or street)

- If you are rural or urban

- If you know your connection is to an exchange, cabinet or conklin

- If your connection is to a ULL or wholesale service

- If you have done an isolation test as per the link above

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

I recommend you read these two blog posts:

- Is your premises phone wiring impacting your broadband performance? (very technical)

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?

I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.

These links are referral codes: Sharesies | Mighty Ape

matisyahu

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#1184560 28-Nov-2014 01:14

It all comes down to how many outlets, where your demark is located etc. I'm around 800-900M from the exchange and I'm sitting at 45Mbps but then again I only have one outlet and the demark goes straight from the mushroom to the outlet, a few cm's of cabling inside along with a master filter then my VDSL modem hooks up to that.

"When the people are being beaten with a stick, they are not much happier if it is called 'the People's Stick'"

DarkShadow

1647 posts

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#1184563 28-Nov-2014 01:22

It's Chorus that sets the max attenuation as they're the ones doing the installation. The ISP gets a prequal before ordering the service, which predicts what attenuation and speeds a particular line would get, but they are often widely inaccurate.

quickymart

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#1184572 28-Nov-2014 06:04

kawaii: It all comes down to how many outlets, where your demark is located etc. I'm around 800-900M from the exchange and I'm sitting at 45Mbps but then again I only have one outlet and the demark goes straight from the mushroom to the outlet, a few cm's of cabling inside along with a master filter then my VDSL modem hooks up to that.

I think you mean demarc ?

sbiddle

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#1184573 28-Nov-2014 06:12

The 10.8dB limit went a long time ago. Now pretty much anything goes.

misha256

24 posts

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#1184609 28-Nov-2014 08:28

sbiddle: The 10.8dB limit went a long time ago. Now pretty much anything goes.

That makes sense. I wonder what impact my 24dB connection has on other users? I'm sure I read somewhere that marginal connections can slow others down.

misha256

24 posts

Geek

#1184666 28-Nov-2014 09:10

kawaii: I'm around 800-900M from the exchange and I'm sitting at 45Mbps...

Wow, that's not bad. Seeing your numbers seriously tempts me to pay Chorus to do some checks/re-wiring at the house. How much difference would a few meters less cabling from demarc make?

From the demarc point there's roughly 10m cable to the splitter, and from the splitter there's another 5~6m to the DSL jack. I'm confident we could get that down to 3m and <1m respectively just by changing the location of the DSL jack.

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Behodar

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#1184669 28-Nov-2014 09:13

sbiddle: The 10.8dB limit went a long time ago. Now pretty much anything goes.

I wish I'd known that six months ago! Oh well, fibre is due "any day now" (possibly today!) :)

CcMaN

87 posts

Master Geek

#1184764 28-Nov-2014 10:44

Signed up for VDSL into the place I was moving into as Chorus/Spark said it was avaliable. Tech came out, and was like "I don't even know why you are bothering, the exchange is 2.5km away and you aren't connected to a cabinet."

Synced fine at 8mbit, but downgraded to ADSL and got same performance. I kind of wish there were publically avaliable maps for exchange locations, as I would not have moved into this place if I had known that I was going to get such poor speeds.

So I think that ISPs are now saying that if there is VDSL avaliable in the exchange, then you are able to connect to it, regardless of distance...

Jase2985

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#1185011 28-Nov-2014 16:22

CcMaN:
Synced fine at 8mbit, but downgraded to ADSL and got same performance. I kind of wish there were publically avaliable maps for exchange locations, as I would not have moved into this place if I had known that I was going to get such poor speeds.

there is a way

http://www.chorus.co.nz/network-upgrade-map

find your address and select the broadband layer and deselect the UFB layers. should be inside a lovely box bordered by white lines. If there is a Dark Brown blob surrounded by ligher brown area and your house in in that area, that means its generally fed from an exchange.

Go to this map here:
http://gis.geek.nz/infrastructure.html#chorus_cabinets

if there is a pink or a light yellow dot in the little white box where your house is it means its fed from a cabinet. you should be able to roughly work out how far it is to the cabinet that feeds your house if you use both maps.

You could be physically closer to one cabinet but it might not be the one that feeds your house

matisyahu

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#1185553 29-Nov-2014 19:34

quickymart:
kawaii: It all comes down to how many outlets, where your demark is located etc. I'm around 800-900M from the exchange and I'm sitting at 45Mbps but then again I only have one outlet and the demark goes straight from the mushroom to the outlet, a few cm's of cabling inside along with a master filter then my VDSL modem hooks up to that.

I think you mean demarc ?

Yeap, you're correct, it is meant to be demarc.

misha256:
kawaii: I'm around 800-900M from the exchange and I'm sitting at 45Mbps...

Wow, that's not bad. Seeing your numbers seriously tempts me to pay Chorus to do some checks/re-wiring at the house. How much difference would a few meters less cabling from demarc make?

From the demarc point there's roughly 10m cable to the splitter, and from the splitter there's another 5~6m to the DSL jack. I'm confident we could get that down to 3m and <1m respectively just by changing the location of the DSL jack.

I remember when I was chatting to the installer he said that the visual distance (from your house to the exchange/cabinet) doesn't always follow that the line will take the same amount of distance - that many times the cable will turn back on itself which can result in a connection that is 1.5/2x's as long as what one expects. The best one I can do I guess is to make sure all the cabling at home is nicely organised, that the distance between the demarc and outlet is kept to a minimum and a filter is installed (which should at least in theory happen with VDSL).

"When the people are being beaten with a stick, they are not much happier if it is called 'the People's Stick'"

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#1185577 29-Nov-2014 21:19

mine is 52dB

bakery2k

79 posts

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#1185642 30-Nov-2014 01:33

I have similar attenuation figures to the OP:

DSL Type: ITU-T G.993.2
Bandwidth (Up/Down) [kbps/kbps]: 2,216 / 17,549
Output Power (Up/Down) [dBm]: 6.3 / 12.7
Line Attenuation (Up/Down) [dB]: 56.4 / 21.5
SN Margin (Up/Down) [dB]: 11.9 / 13.8

Jase2985:
http://www.chorus.co.nz/network-upgrade-map

find your address and select the broadband layer and deselect the UFB layers. should be inside a lovely box bordered by white lines.

Our address is near the middle of one of the white-bordered areas - the area is probably 800m across at its widest.

Jase2985:
Go to this map here:
http://gis.geek.nz/infrastructure.html#chorus_cabinets

if there is a pink or a light yellow dot in the little white box where your house is it means its fed from a cabinet. you should be able to roughly work out how far it is to the cabinet that feeds your house if you use both maps.

Unfortunately there is no sign of a dot within our area, nor any of the immediately surrounding areas.

Given this information, is it possible to say how far I might be from a cabinet/exchange? If so, do my figures above look reasonable?

RunningMan

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#1185675 30-Nov-2014 08:11

Do you remember what your ADSL attenuation was prior to VDSL as the 10.8dB was the rule of thumb for the pre VDSL attenuation.

VDSL attenuation is measured at a different frequency to ADSL so it will show as higher than the ADSL.

plambrechtsen

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#1185716 30-Nov-2014 10:28

Your VDSL Attenuation will be approximately 2.5X higher than your ADSL attentuation. Since the frequency bandwidth is much higher than with ADSL.

Your downstream is 18mb and upstream is 6mb so then you are doing pretty well.

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