VM carried out some work in the EH11 area during mid June 2012. Since then the lower end downstream power levels on our line/SH have changed significantly. Can someone advise please as to these values, shown below, as they appear outside the recommended values, also shown below, in the Power Level Primer (sephiroth) available on this forum?
There are two attenuators on the line – one 3dB forward path and one 10dB forward path. These were added by VM and have not been adjusted, as it were, since the June 2012 work.
Sephiroth Power Level Primer values
256QAM | -3 to + 7 dBmv | -≥ 34.5 dB
Current SH June 2012 levels
Locked | QAM256 | 78 | 55616000 Kbits/sec | 307000000 Hz | -6.0 dBmV | 39.5 dB
Locked | QAM256 | 76 | 55616000 Kbits/sec | 291000000 Hz | -5.7 dBmV | 39.4 dB
Locked | QAM256 | 77 | 55616000 Kbits/sec | 299000000 Hz | -5.8 dBmV | 39.9 dB
Locked | QAM256 | 79 | 55616000 Kbits/sec | 315000000 Hz | -6.2 dBmV | 38.7 dB
Locked | QAM256 | 80 | 55616000 Kbits/sec | 323000000 Hz | -6.4 dBmV | 40.0 dB
Power values from April 2012 (pre VM work)
Locked | QAM256 | 59 | 55616000 Kbits/sec | 315000000 Hz | 4.0 dBmV | 41.8 dB
Locked | QAM256 | 57 | 55616000 Kbits/sec | 299000000 Hz | 3.6 dBmV | 41.4 dB
Locked | QAM256 | 58 | 55616000 Kbits/sec | 307000000 Hz | 3.9 dBmV | 42.0 dB
Locked | QAM256 | 60 | 55616000 Kbits/sec | 323000000 Hz | 4.1 dBmV | 41.8 dB
The upstream value has dropped by 4dB but is still within recommended range.
Thank you for any advice/assistance offered.
chrisk4
