Cable Forum - View Single Post - SNR problem.. and strange modem parameters

ccarmock · 07-11-2011, 22:26

I ave been suffering a problem with loss of sync on the 10 Mb/s business package - with an EPC2100 modem.

When sync is lost this is usually accompanied by SNR falling from the usual 40-41 dBmV to around 15 or 10 dBmV

Usually downstream channel number is 7, but today I am seeing strange parameters:-

Locked
Channel ID 228
Downstream Frequency 299000000 Hz
Modulation 256QAM
Bit Rate 55616000 bits/sec
Power Level 1.9 dBmV
Signal to Noise Ratio 38.4 dB

Upstream was stuck at:-

Upstream Status Ranging
Channel ID 2
Upstream Frequency 25800000 Hz
Modulation 16QAM
Symbol Rate 10240000 bits/sec
Power Level 40.5 dBmV

This then usually flips to QPSK on this channel and works for 5-10 mins and sync is lost again.

VMB say they will look into it. Is this usually noise on the network or an indication of a faulty modem?

07-11-2011, 22:26	#1
ccarmock cf.geek Join Date: Jun 2008 Posts: 804	SNR problem.. and strange modem parameters I ave been suffering a problem with loss of sync on the 10 Mb/s business package - with an EPC2100 modem. When sync is lost this is usually accompanied by SNR falling from the usual 40-41 dBmV to around 15 or 10 dBmV Usually downstream channel number is 7, but today I am seeing strange parameters:- Locked Channel ID 228 Downstream Frequency 299000000 Hz Modulation 256QAM Bit Rate 55616000 bits/sec Power Level 1.9 dBmV Signal to Noise Ratio 38.4 dB Upstream was stuck at:- Upstream Status Ranging Channel ID 2 Upstream Frequency 25800000 Hz Modulation 16QAM Symbol Rate 10240000 bits/sec Power Level 40.5 dBmV This then usually flips to QPSK on this channel and works for 5-10 mins and sync is lost again. VMB say they will look into it. Is this usually noise on the network or an indication of a faulty modem?