Are my power levels to high?

[SD1234]

Hi all,

I have mentioned this in my other thread here http://community.virginmedia.com/t5/Fibre-optic-broadband-cable/What-the-hell-is-going-on-packet-los...

but it seems my question is being over looked due to the title so appoligies for repeating myself,

Here are my stats, are they to high?

Acquire Downstream Channel 298750000 Hz Locked Connectivity State OK Operational Boot State OK Operational Configuration File OK   Security Enabled BPI+

Downstream Channels Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power SNR Docsis/EuroDocsis locked Locked QAM256 78 55616000 Kbits/sec 298750000 Hz 19.9 dBmV 44.3 dB Hybrid Locked QAM256 79 55616000 Kbits/sec 306750000 Hz 18.8 dBmV 44.1 dB Hybrid Locked QAM256 80 55616000 Kbits/sec 314750000 Hz 18.6 dBmV 43.8 dB Hybrid Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown

Upstream Channels Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power Locked ATDMA 1 20480 Kbits/sec 45800000 Hz 36.2 dBmV Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

Primary Downstream Service Flow Downstream(0) SFID 5014 Max Traffic Rate 33330000 bps Max Traffic Burst 3044 bytes Mix Traffic Rate 0 bps

Primary Upstream Service Flow Upstream(0) SFID 5013 Max Traffic Rate 3333000 bps Max Traffic Burst 8160 bytes Mix Traffic Rate 0 bps Max Concatenated Burst 8160 bytes Scheduling Type Best Effort

[SD1234]

COYS - bump

[jhuk]

The downstream is far too high going by that guide in sticky at top of this section that says :

DOWNSTREAM POWER (Optimal)

Rule of thumb: -3 dBmv to +6 dBmv

The above advice compares with the VM stated optimum values by region (according to implemented infrastructure standards) and modulation:

QAM64 (Knowsley networks) -7 dBmv to +3 dBmv

QAM64 (Langley/Bromley) -10 dBmv to 0 dBmv

QAM256 -3 dBmv to +7 dBmv

An attenuator could fix that unless its a network issue !

[SD1234]

yeah i did read that post but was unsure if that applied to the super hub as it doesnt look like its been updated in a while, and this is what it says at the beginning

The CMs are advertised with a wider power range than is considered healthy for a stable connection.  For example, the Ambit 256 modem is spec'd for downstream in the range -15 to +15 dBmv (slight variations according to 64QAM or 256QAM but these are ignored for the purpose of this article.  There are also variations attributable to the local implementation of DOCSIS or EURODOCSIS which employ different channel bandwidth and frequency plans; these variations are also ignored for the puroses of this article.

[big-luap]

Mine were between 11 & 12, an engineer fited a 6Db attenuator which brought them down to 6.

So yes, yours are definately way to high.

Refer to: POWER LEVELS & SNR: A TECHNICAL PRIMER by Sephiroth

High downstream power amplifies noise (but if the CM is close to the street cabinet, SNR wiill be high and noise will be low).  High downstream power also overdrives the CM amplifier, but not all CMs are as sensitive as each other.  So this is a moving target.

[SD1234]

Did this improve your general speed over wireless and wired?

Currently get about 24 wired and 12-15 wireless (being in the same room as the router)

[Lee_G]

Hi SD1234

I can see that my colleague Ray has picked up your issue in the other thread.  Once you have sent him a PM with the times you're available for an engineer we will arrange this for you.