WiFi Harmonics

[uxbod]

Hi,

I have a Cisco AP and have found when it is active my DSL SNR increases massively! At first I thought it was the bell ring circuit, but after disconnecting that all was good, I thought Now I am getting massive spikes, so how can I reduce this ? Is shielded phone cable available ?

TIA.

[Sebby]

I think that most, if not all, wireless access points have this effect, but perhaps this one is particularly bad. Certainly you'll find that there is a lot of noise around the router if you were using a de-tuned MW radio. As far as what you can do about it, I'm not too sure, but perhaps someone else can offer some suggestions.

[Rik]

What's the layout relative to the master socket, ie where's the router and where's the AP, and what sort of lengths of cable are involved.

[uxbod]

Couple of metres from the master socket, both the router and AP.  The AP is on the wall above it.  Will see if I can move the router closer to the socket, and perhaps in a small rack aswell.

[Rik]

That's not a huge length of lead, though, unless the noise is being picked up on the phone wiring. Are you using, or could you use, a filtered face plate?

[uxbod]

I have another inactive phone line (missus old business line) so I may get that activated and switch the DSL across to that line.  That socket has no extensions on it at all.  It was a feature line but will get them to make it a standard line with a normal master socket on it.  I can then add a filtered faceplate aswell.

If of interest for some stats :-

http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-snr.html
http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-att.html
http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-linespeed.html

[Rik]

Is the Rx speed the throughput or the sync? If the former, it seems very low for a 46db line.

[uxbod]

This is what the Cisco reports

Code Select Expand

cisco877#sh dsl interface atm0
ATM0
Alcatel 20190 chipset information
ATU-R (DS) ATU-C (US)
Modem Status: Showtime (DMTDSL_SHOWTIME)
DSL Mode: ITU G.992.1 (G.DMT) Annex A
ITU STD NUM: 0x01 0x1
Vendor ID: 'STMI' 'ALCB'
Vendor Specific: 0x0000 0x0000
Vendor Country: 0x0F 0x0F
Chip ID: C196 (0)
DFE BOM: DFE3.0 Annex A (1)
Capacity Used: 98% 49%
Noise Margin:   9.5 dB 23.0 dB
Output Power: 17.0 dBm 12.0 dBm
Attenuation: 46.0 dB 29.0 dB
Defect Status: None                            None                       
Last Fail Code: None
Watchdog Counter: 0x84
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction: 0x00
Interrupts: 12433 (0 spurious)
PHY Access Err: 0
Activations: 6
LED Status: ON
LED On Time: 100
LED Off Time: 100

Init FW: init_AMR-3.0.014_no_bist.bin

Operation FW: AMR-3.0.014.bin

FW Source: embedded
FW Version: 3.0.14

Interleave Fast Interleave Fast
Speed (kbps):        3264            0        448            0
Cells:     4293849            0   78001293            0
Reed-Solomon EC:      15795            0         56           42

CRC Errors:        1822            0         51           27
Header Errors:        1605            0         22           12
Total BER:   65535E-255 0E-0
Leakage Average BER:   65535E-255 0E-0
ATU-R (DS) ATU-C (US)
Bitswap:        enabled   enabled

Bitswap success:          0               0
Bitswap failure:          0               0


[Rik]

Well, I read that as a sync of 3264k on a 46db attenuation. I go faster than that at 57db attenuation. Do you have an NTE5 master socket, the type where the bottom part of the faceplate can be detached? If so, have you tried connecting at the test socket behind the faceplate?

[uxbod]

Yup, Andrew (IDNET) suggested that and it did help a little.  I did remove the bell ring circuit aswell.  I think the problem is my AP as it is damn good.  Can get to bottom of garden with full strength Need to have a play.  Nobody is going to phone tonight, and we are moving to all VoIP, so will slap it in and give it a try.

[uxbod]

Am on the test socket now, so see how the stats go

[Sebby]

If you are using the test socket, the ring wire has no effect (the same goes for using a filtered faceplate), as the signal is terminated before the extension wiring.

[uxbod]

Correct. Attempting to isolate the problem., whether internal wiring is causing harmonics

[uxbod]

Latest update :- http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-snr.html

I have left it connected to the master socket all night and my other half has been using the WiFi for a couple of hours this morning, and it would appear no problems at all.

Best bet do you think would be to get a filtered front-plate ?

[Rik]

Yes.

http://www.adslnation.com/products/xte2005.php

[uxbod]

Ordered.  Cheers Rik

[uxbod]

Hope it comes soon! On the master socket still and look at the linespeed

http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-linespeed.html

[Sebby]

Great. Internal wiring is so often the cause.

[Rik]

Looks like you should have the cure shortly, Ux.

[uxbod]

Well the fantastic people at ADSLNation shipped my faceplate on Friday and it arrived Saturday morning

I have just fitted it and all I can say is 

http://www.splatnix.net/cgi-bin/mrtg-rrd.cgi/cisco-linespeed.html

What a difference it has made About a 25% increase in sync speed :D:D

[Rik]

Much better.  

[Inactive]

A result uxbod, well done.. 

[Sebby]

Excellent result. It's quite amazing what a negative impact internal wiring can have. Every house should have a filtered faceplate fitted (I suspect something like that will be come the norm one day), though of course the positioning of the master socket isn't always convenient for everyone.