FTTC Line Attenuation - Distance from Cabinet.

Hi Guys.

My Line Attenuation is 13.9, and wondering what distance is like to the cabinet. Is their a calcautor for it? Like ADSL2+.

Just Curious what it is.

My Stats are:

Line Status
Downstream Upstream
Attainable rate (kbit/s) 120076 39611
SNR margin (dB) 18.6 22.8
Line attenuation (dB) 13.9 0
Output power (dBmV) 13.3 4.6

Statistics

Path 0
Path 1
Downstream Upstream Downstream Upstream
Line rate (kbit/s) 79987 19999 0 0
CRC errors 0 0 0 0
FEC errors 984 52 0 0
HEC errors 2191 0 0 0

The cabinet is only going to be a couple of hundred metres away ... can you locate it and pace out the distance?

JB68

At those attainable rates you ought to fall over it outside your gate!!

120Mb downstream 40Mb upstream is the tops.

Stand outside you gate and you should see the Cab, you can then measure the distance with a reasonable Tape measure..

I used a walking GPS app to measure my distance from my cab and also used google maps too.

Just need to find cab, and follow BT/PO Manholes on the ground really.

Hi. It's about 300 metres away road distance. I must have a good line. Haha.

Well this website say 300m should be full speed

http://www.increasebroadbandspeed.co.uk/2013/chart-b...

But yes I would say you have a very good line though maybe not as long as 300 metres.

mine is supposed to be around 300-350 metres so I hope when I finally get it, I will match your results..

Yeah I think the line is quite short to it.

In reply to a post by JB68:

Hi. It's about 300 metres away road distance. I must have a good line. Haha.

No, it cannot be 300m away because last february bt engineer told me that my fibre cabinet is 200m away from my house, just 1 minute walk away from it. I am getting 113136 kbps downstream and 38605 kbps upstream.

I think your is likely to be around 150m away.

Edited by adslmax (Sat 17-May-14 01:06:39)

In reply to a post by adslmax:

In reply to a post by JB68:

Hi. It's about 300 metres away road distance. I must have a good line. Haha.

No, it cannot be 300m away because last february bt engineer told me that my fibre cabinet is 200m away from my house, just 1 minute walk away from it. I am getting 113136 kbps downstream and 38605 kbps upstream.

I think your is likely to be around 150m away.

Or he could have a newer / better quality cable connecting him to the cabinet, with less joints, maybe.

In reply to a post by JB68:

Hi Guys.

My Line Attenuation is 13.9, and wondering what distance is like to the cabinet. Is their a calcautor for it? Like ADSL2+.

Just Curious what it is.

My Stats are:

Line Status
Downstream Upstream
Attainable rate (kbit/s) 120076 39611
SNR margin (dB) 18.6 22.8
Line attenuation (dB) 13.9 0
Output power (dBmV) 13.3 4.6

Statistics

Path 0
Path 1
Downstream Upstream Downstream Upstream
Line rate (kbit/s) 79987 19999 0 0
CRC errors 0 0 0 0
FEC errors 984 52 0 0
HEC errors 2191 0 0 0

My line length to the cab according to an Openreach engineer is 120Meters (which to be fair looks about right looking at it)

6. Data rate: 20000 / 79995
7. Maximum data rate: 33988 / 109793
8. Noise margin: 15.6 / 14.3
9. Line attenuation: 0.0 / 5.8

My attainable rates were very similar to yours when i was the only person using it.

As i have an identical ds attenuation to the OP, any idea why the max attainable speed on my FTTC connection is ~ 86000 kbps instead of 120000 kbps?

And why are some connections like mine and OPs only able to sync at 79987kbps instead of 80000kbps? Perhaps its a bug inside unlocked HG612 fw?
Cheers

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 31929 Kbps, Downstream rate = 86216 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79987 Kbps

Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 7.9 15.0
Attn(dB): 12.7 0.0
Pwr(dBm): 12.8 0.8
VDSL2 framing
Bearer 0
MSGc: 18 26
B: 239 237
M: 1 1
T: 23 42
R: 0 16
S: 0.0955 0.3781
L: 20104 5374
D: 1 1
I: 240 127
N: 240 254
Counters
Bearer 0
OHF: 166100253 1580245
OHFErr: 741 87
RS: 0 2453335
RSCorr: 0 713
RSUnCorr: 0 0

Bearer 0
HEC: 1304 0
OCD: 34 0
LCD: 34 0
Total Cells: 3582122852 0
Data Cells: 1332108251 0
Drop Cells: 0
Bit Errors: 0 0

ES: 485 69
SES: 0 0
UAS: 29 29
AS: 274709

Bearer 0
INP: 0.00 0.00
INPRein: 0.00 0.00
delay: 0 0
PER: 1.65 3.98
OR: 116.09 64.22
AgR: 80103.09 20063.54

Bitswap: 133775/133775 2485/2485

Total time = 1 days 4 hours 18 min 58 sec
FEC: 0 713
CRC: 741 87
ES: 485 69
SES: 0 0
UAS: 29 29
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 3 min 58 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 3 0
ES: 2 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 4 hours 18 min 58 sec
FEC: 0 31
CRC: 35 1
ES: 20 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 0 211
CRC: 186 33
ES: 115 19
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 3 days 4 hours 18 min 27 sec
FEC: 0 713
CRC: 741 87
ES: 485 69
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
#
ATP>




Last initialization procedure status: 0
Max: Upstream rate = 31941 Kbps, Downstream rate = 86216 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 79987 Kbps

Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3970)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3970)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 31941 kbps 86216 kbps
Actual Aggregate Tx Power: 0.8 dBm 12.8 dBm
====================================================================================
VDSL Band Status U0 U1 U2
U3 U4 D1 D2 D3
Line Attenuation(dB): 3.1 14.4 21.0 N/A N/A 8.0 17.4
26.4
Signal Attenuation(dB): 3.1 13.6 20.6 N/A N/A 9.1 17.3
26.4
SNR Margin(dB): 14.6 14.6 15.2 N/A N/A 7.9
7.9 7.9
TX Power(dBm): -13.5 -29.2 0.7 N/A N/A 9.0
7.8 7.0
#
ATP>

FTTC is capped at 76 down and 20 up at max
if distance is less that 500 metres would suggest in excess of 40m/bps at a network level

Yes i'm fully aware that FTTC is capped at 80/20 but out of curiousity i want to know why the max attainable rate on my line is 86 meg yet the OP has 120 meg despite both of us having a ds attenuation of 12-13 db.

Perhaps he's on a different profile?

We're both on fastpath mate

There are 3 DLM profiles and fastpath isn't one of them.

3 DLM profiles are Standard, Speed & Stable. There is no fastpath on FTTC.

Most likely one of

1. Cross talk levels are different
2. Different power mask, i.e. not all cabinets put out same level of signal, three power levels to avoid cross talk killing ADSL2+
3. Presence of a noise source not enough to impact connection speed, but max attainable

I did recently get a new line about 4 years ago, I say the Line Length is at least 250 metres.

Your SNR/SNRM is lower, indicating a 'noisier' connection which will impact attainable rates & for those unable to achieve the full whack due to distance, actual sync speeds.


'Noise' can be from many varied sources.
My connection has seen increased 'noise' due to crosstalk over an 18 month period as more users have been connected.

As I am 1100m or so from the cabinet, my sync speeds have gradually deteriorated from around 30 Mbps DS to currently around 19 Mbps.

It was around 22 Mbps until yesterday - assumption is someone else was connected recently as My SNRM has been running as low as 5 dB for a while.

This morning's resync restored the 6dB margin, but that has reduced actual sync speed accordingly.

Edited by deleted (Tue 20-May-14 08:31:44)

You should be very grateful for a line of that quality.
My cabinet is <50m away even if the cable takes a very indrect route but my attainable has dropped over time from close to the max to around 70mbit now.
This is still great but being so close I would have liked a bit of headroom for future speed increases when available.

I was kind of wondering myself on how far I am away from my cabinet too.

These are my stats from my Homehub 5.....

4. Board version: BT Hub 5A
6. Data rate: 20000 / 79995
7. Maximum data rate: 37665 / 103336
8. Noise margin: 18.5 / 12.4
9. Line attenuation: 0.0 / 13.2
10. Signal attenuation: 0.0 / 13.3

Also, I'm connected at 79995, which according to the HH5 is 78.12 Mbps. When I'm doing speed tests, I'm getting around 74 Mbps and 74.8 Mbps. Is this normal guys?

Thanks!

Yea very normal. I get about 74-75mbps

How do you find out what profile you are on?

Perfectly normal ...

As for distance - somewhere around 250 to 350 metres. Remember it is from your house to the original (PSTN) cabinet and then from there back to the VDSL cabinet.

In reply to a post by smouty:

My cabinet is <50m away even if the cable takes a very indrect route but my attainable has dropped over time from close to the max to around 70mbit now.

I think i'll be joining your club soon mate. I'm still connected at the max @ 79987kbps but my max attainable has dropped from 86meg to 83meg (crosstalk?) so its only a matter of time before my sync speed drops as well

Post deleted by DarkKobra1977

My speed dropped from 71 Mbps to 48 Mbps in one go and the Openreach engineer who came to sort it out says that 48 is the highest speed the line has ever supported. When I showed him proof of the original speed and he just said "the stats from the modems aren't accurate", Unbelievable

I think he was a genuine Openreach engineer because he turned up in a proper Openreach vans.

My guess he was either an Arsenal or Hull fan given that it was 1:30pm Saturday afternoon because he seemed to be in a bit of a hurry and he never ran any tests from the test socket only from the sockets on the filter.

In reply to a post by MHC:

Perfectly normal ...

As for distance - somewhere around 250 to 350 metres. Remember it is from your house to the original (PSTN) cabinet and then from there back to the VDSL cabinet.

This is correct. My FTTC was approx 242m away but FTTC Cabinet to PSTN cabinet are within 50m to make it 292m away (this the max length for G.fast 229 from 330)

However, G.fast is served from a pod on your PCP (what you call "PSTN cabinet"), not from the VDSL cabinet, so you benefit from the shorter line length.

Why on earth have you woken up a 2014 thread? (Maybe a removed spam post did it and you didn�t notice).

Quite apart from your calculation of your FTTC distance is wrong; G.Fast wasn�t around until 2017; and even if it had been isn�t relevant to the OP�s question.

In reply to a post by RobertoS:

Why on earth have you woken up a 2014 thread?

I know its normal for threads on this forum to be left open but because of that it does allow for these sort of things to happen

I do think there is a case for once a thread has been dormant for x period of time (say 6 months) they could be locked, they can always be referenced in a new thread if required/relevant.

It could be coded in so it locks automatically after x period of time so not to cause any additional work for the moderators

In reply to a post by RobertoS:

Why on earth have you woken up a 2014 thread?

What wrong with it? The forum are always open & no matter what year is it. I could post here in 20 years time! haha

Post deleted by busterboy

Edited by busterboy (Tue 28-Jan-20 21:51:28)

But "My FTTC was approx 242m away but FTTC Cabinet to PSTN cabinet are within 50m to make it 292m away" is still incorrect arithmetic.

If my line length are 242m from my master socket to FTTC cabinet, then how many metres from the FTTC cabinet to PSTN cabinet?

Your master socket does not go to the FTTC cabinet. It goes direct to the PCP. From there the signal in either direction goes to the DSLAM in the FTTC cabinet then returns, with the VDSL2 either added (downstream from your point of view) or removed (upstream from your point of view), depending on direction of signal.

Your FTTC distance is the distance to the PCP (P) plus the distance from that to the FTTC (D) cabinet. You said distance to the FTTC cabinet plus the distance to the PCP. You said:-

My FTTC was approx 242m away but FTTC Cabinet to PSTN cabinet are within 50m to make it 292m away

Take two simple cases using your 242m to the FTTC cabinet. I'll use 50m as the distance between the two cabinets but the actual value doesn't matter:-

1) The PCP is between you and the FTTC cabinet, in a straight line. FTTC distance is the distance to the FTTC cab, 242m.

2) The FTTC cabinet is between you and the PCP in a straight line, which is sort of what you described. FTTC distance is the distance to the PCP (242 + 50 = 292 as you calculated) plus another 50m for the link between the two. 342m. The signal from you has to go to the PCP then to the FTTC then back to the PCP.

Post deleted by RobertoS, it was duplicated due to lag.

Edited by RobertoS (Wed 29-Jan-20 01:53:47)