A small problem...

[Enigma776]

Hello,

I had A VM engineer come out today to replace my TV box from a pace to the new samsung, while he was testing he said my rates were on the low side and wanted to look at my modem as well just to make sure everything was fine there. T

here was degradation of the TV but that changed once the new box was fitted.

Now this is where the problem lies he change the attenuator on my modem from 2 4db (each end) to a single 6db on the modems end, ever since my internet speed has dropped dramatically from my usual 20mb service to what appears to be a 2mb service.

I am from Peterborough and have tested the following my self ;

I tried an old 10db attenuator and got no change, Tried to see if it was my network which it is not.

Network layout is 2 Computers both running windows XP one on SP2 the other on SP3 and a linksys WRT54GS V2 running DD-WRT and a small blue NTL modem.

Trace Route from BBC.co.uk

1 <1 ms <1 ms <1 ms 192.168.1.254
2 25 ms 39 ms 17 ms 10.45.0.1
3 14 ms 8 ms 7 ms pete-t2cam1-a-ge96.inet.ntl.com [80.3.130.21
4 9 ms 28 ms 24 ms pete-t2core-a-ge-wan61.inet.ntl.com
[195.182
5 12 ms 11 ms 11 ms nth-bb-a-so-710-0.inet.ntl.com [62.253.188.2
6 15 ms 15 ms 15 ms gfd-bb-b-so-010-0.inet.ntl.com [62.253.185.9
7 37 ms 32 ms 15 ms redb-ic-1-as0-0.inet.ntl.com [62.253.185.78]
8 14 ms 15 ms 42 ms 212.58.238.189
9 14 ms 17 ms 14 ms 212.58.238.133
10 33 ms 18 ms 36 ms rdirwww-vip.thdo.bbc.co.uk [212.58.224.131]

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation :
QAM64 Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -9.7 dBmV
Downstream SNR : 28.5 dB

Speed test info;
https://www.cableforum.co.uk/images/local/2008/02/7.png (http://www.speedtest.net)

If anyone could shed some light on it, I would be grateful.

Enigma

[fatassmichael]

Hi Enigma, your downstream power level is to low, have you tried without the attenuator?

[Enigma776]

Sadly I have and it's still the same which bothers me.

[fatassmichael]

Sounds like another call to tech supp is needed, failing that you can use the newsgroups.

[Druchii]

Downstream SNR : 28.5 dB

There's your problem... Should be at 30dB at least for a connection to work even remotely correctly.

[Enigma776]

So this engineer I had out today crippled me huh damn it.

I'll give the no attenuator another go and report back any changes.

--Edit--

Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -4.0 dBmV
Downstream SNR : 28.8 dB

It actually seems to be worse with it out.
https://www.cableforum.co.uk/images/local/2008/02/6.png (http://www.speedtest.net)

Just looked at my Digi box and that has no attenuators on it at all is this normal?

[fatassmichael]

Downstream SNR : 28.5 dB

There's your problem... Should be at 30dB at least for a connection to work even remotely correctly.

Not on QAM64 Modulation, although your right, higher would be better.

[Enigma776]

I decided to post the first message on the newsgroups seems like an engineer will be coming out to sort it.

I would like to thank you guys for your time.

[Druchii]

Not on QAM64 Modulation, although your right, higher would be better.
Hmm, could of sworn everywhere had gone upto 256QAM,gah, better take a closer look next time :(

[Mick Fisher]

Still on QAM64 here but after recent maintenance on the Northampton UBR I notice my upstream is now QAM16, I'm sure it was QAM64 before. Also my upstream transmit power level went from 48 to 57. It's dropped back to 53.5 now though.
Anyone have a clue what's going on? BB is still working but struggles to reach 10meg most of the time, as per usual. Mind you that's according to speedtest.net which is probably not very accurate.