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Understanding SNR and Attenuation Rates

325i

Senior Member
Joined
Jan 1, 2011
Messages
530
Call your ISP and ask them to reset your sync profile.
Have phoned Telkom numerous times and asked for a port reset? same thing? even a techie came out but all I got was a call asking if everything was good (speeds actually decreased before he could call)

Hi 325i. Looking at your attenuation of 50.1 dB, the length of your copper wire to the exchange is 3,6 km. That’s tough, especially for ADSL2+.

*snip*
is there a way to change from adsl2+ to adsl/adsl2 or is it set by telkom and not able to be changed?
 

bokka1

Expert Member
Joined
Nov 27, 2006
Messages
2,743
Have phoned Telkom numerous times and asked for a port reset? same thing? even a techie came out but all I got was a call asking if everything was good (speeds actually decreased before he could call)



is there a way to change from adsl2+ to adsl/adsl2 or is it set by telkom and not able to be changed?
You do it on your router.
 

325i

Senior Member
Joined
Jan 1, 2011
Messages
530
You do it on your router.
On which routers am I able to do this? I know I currently have a budget Huawei (HG 532s) one which basically just allows me to log into my data account and change my Wi-Fi password. (Has portforwarding/nat/etc but other than that it's basic)
 

5IVE

New Member
Joined
Oct 6, 2017
Messages
8
hi
i have a 4 mbps uncapped line with telkom and wanted to upgrade to 10 mbps line but according to telkom website my area supports only 4 mbps i phoned once and asked if my area supports 10 they told me no but the block next to my block supports 10 mbps i realyy wanna upgrade so is there any way forme to get 10 mbps speed

router details

Downstream Line Rate (Kbps): 5119
Upstream Line Rate (Kbps): 508
Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (dB): 56 177
Attenuation (dB): 570 344
Output Power (dBm): 0 128
Attainable Rate (Kbps):5880 988
D (interleaver depth): 96 1
Delay (msec): 15.90 1.13
 

Johnatan56

Honorary Master
Joined
Aug 23, 2013
Messages
19,415
You do it on your router.
No, you can force it to only accept ADSL2 sync, but there's no point.
Staying at ADSL2+ is better as it has access to more frequency spectrum, there are no negatives. It's the same as VDSL always being better than ADSL, but there are cases where the difference is negligible (when you're too far from the exchange).

hi
i have a 4 mbps uncapped line with telkom and wanted to upgrade to 10 mbps line but according to telkom website my area supports only 4 mbps i phoned once and asked if my area supports 10 they told me no but the block next to my block supports 10 mbps i realyy wanna upgrade so is there any way forme to get 10 mbps speed

router details
Code:
Downstream Line Rate (Kbps):	5119
Upstream Line Rate (Kbps):	508
                                                  Downstream     Upstream
Line Coding(Trellis):	On 	On 
SNR Margin (dB):	56 	177 
Attenuation (dB):	570 	344 
Output Power (dBm):	0 	128 
Attainable Rate (Kbps):5880 	988 
D (interleaver depth):	96 	1 
Delay (msec):	15.90 	1.13
I would say no, you've got 5.6dB SNR downstream. Under 6dB it will start disconnecting you at times. Pushing it higher would be a bad idea.
 

Serene

Expert Member
Joined
Sep 24, 2008
Messages
1,614
Hi My'bbers,

I'm posting the following wrt the storms we had this past week..As you know I posted my stats when they came and installed and fixed my line.

Here is my new stats with screenshots.Thing that is worrying me on the speed test is that the one shows a "low" DL speed while the other one shows my "normal" DL speed.I also noticed the ping on the speedtest is usually anything from 20ms-45ms and now sometimes it spikes to 250-300ms and then back to normal.You will see this also in screenshots.

Also attached is my router stats.My question is should I be worried that it spikes between high and low and do you have any suggestions as to testing or/and what are my options or am I stressed out for nothing.I did plug out everything before the storm but do you think there is damage on the line/exchange?


Your help is greatly appreciated.



high.jpg

low.jpg

router.jpg
 
Last edited:

beesboertjie

Senior Member
Joined
Jun 13, 2017
Messages
520
Hi Grandmaster Serene. My two cents. Your downstream attenuation is 40,5 dB which means the length of your copper wire to the exchange is 2,9 km. As you know, that is not ideal. If not too far, then almost too far.
 

Johnatan56

Honorary Master
Joined
Aug 23, 2013
Messages
19,415
Hi My'bbers,

I'm posting the following wrt the storms we had this past week..As you know I posted my stats when they came and installed and fixed my line.

Here is my new stats with screenshots.Thing that is worrying me on the speed test is that the one shows a "low" DL speed while the other one shows my "normal" DL speed.I also noticed the ping on the speedtest is usually anything from 20ms-45ms and now sometimes it spikes to 250-300ms and then back to normal.You will see this also in screenshots.

Also attached is my router stats.My question is should I be worried that it spikes between high and low and do you have any suggestions as to testing or/and what are my options or am I stressed out for nothing.I did plug out everything before the storm but do you think there is damage on the line/exchange?


Your help is greatly appreciated.
Next time crop it in e.g. paint and/or upload it to imgur and post image via URL, MyBB degrades the image for storage purposes.


That looks like an ISP issue and not a line issue, your line stats are fine for 4Mbps.
 

Serene

Expert Member
Joined
Sep 24, 2008
Messages
1,614
Next time crop it in e.g. paint and/or upload it to imgur and post image via URL, MyBB degrades the image for storage purposes.


That looks like an ISP issue and not a line issue, your line stats are fine for 4Mbps.
Will do so.Sorry if it caused any inconvenience.

This mornings speedtest show on wifi

3.96mbps DL

0.35mbps UL

42ms Ping
 

Johnatan56

Honorary Master
Joined
Aug 23, 2013
Messages
19,415
Will do so.Sorry if it caused any inconvenience.

This mornings speedtest show on wifi

3.96mbps DL

0.35mbps UL

42ms Ping
Inconvenience is due to me having trouble reading pixelated text. :p
There's a share button, those stats mean nothing without knowing where the server is hosted. If it's under 50 miles the latency is a bit high but explainable as you're on interleaved, if it's over, that's fine for 4Mbps.
Just ping bras.afrihost.com, paste it in
Code:
 [ /CODE] brackets here, it will keep the format. Please do so using an Ethernet connected device, WiFi has so many other factors that can influence your latency.
Bras is your exchange. I'm on fiber so mine is a lot lower than yours, but you should have around/just under 25ms because you're on interleaved. On ADSL I had ~8-16ms on fast path. 

[code]
C:\WINDOWS\system32>ping bras.afrihost.com

Pinging bras.afrihost.com [155.239.255.250] with 32 bytes of data:
Reply from 155.239.255.250: bytes=32 time=3ms TTL=63
Reply from 155.239.255.250: bytes=32 time=3ms TTL=63
Reply from 155.239.255.250: bytes=32 time=4ms TTL=63
Reply from 155.239.255.250: bytes=32 time=2ms TTL=63

Ping statistics for 155.239.255.250:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 2ms, Maximum = 4ms, Average = 3ms

C:\WINDOWS\system32>
 

jdido87

Senior Member
Joined
Nov 10, 2014
Messages
545
I need some advice, my router keeps loosing sync but the line stats are all fine. I had telkom there and their removed the ASSIA profile but the issue persists. I notice a slight jump in downstream attenuation but its back to normal but the issue persists.
 

Johnatan56

Honorary Master
Joined
Aug 23, 2013
Messages
19,415
I need some advice, my router keeps loosing sync but the line stats are all fine. I had telkom there and their removed the ASSIA profile but the issue persists. I notice a slight jump in downstream attenuation but its back to normal but the issue persists.
What's the actual stats and have you tried removing all devices and just plugging the router straight into the wall? At what times/weather conditions does your line go down?
 

jdido87

Senior Member
Joined
Nov 10, 2014
Messages
545
What's the actual stats and have you tried removing all devices and just plugging the router straight into the wall? At what times/weather conditions does your line go down?
We dont see much rain here in Cape Town so I doubt its weather. Stats are snr down 18db attention down 48db. This is on a 4mb that synced on 5mb without issue. Seeing lots of CRC errors lately. Was +20k when I got home today. I set the router to G.mdt instead of ADSL2+ which its on normally.
 

beesboertjie

Senior Member
Joined
Jun 13, 2017
Messages
520
Hi jdido87. According to your downstream line attenuation of 48 dB, the length of your copper wire to the exchange is 3½ km. Unfortunately, that is not ideal.

attenuation-copper-length-km.png
 

Johnatan56

Honorary Master
Joined
Aug 23, 2013
Messages
19,415
We dont see much rain here in Cape Town so I doubt its weather. Stats are snr down 18db attention down 48db. This is on a 4mb that synced on 5mb without issue. Seeing lots of CRC errors lately. Was +20k when I got home today. I set the router to G.mdt instead of ADSL2+ which its on normally.
There's no real point setting it to normal ADSL, it doesn't really improve anything.

Try unplugging all devices and connecting directly to the wall. I doubt it will help you though, it sounds more like a line fault.
 
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