What affects power levels?

Horace · 27-04-2007, 19:23

I had a visit from an engineer on Wednesday, my downstream power level was around -3 which his said was ok, I was under the impression that levels greater than 0 were in spec for QAM256. He swapped my modem out for a 255 to cure the rebooting problems, which it did , did a speed test at speedtest.net which came out at around 8 meg, I was happy as I hadn't even hit 5meg over the last 4 months.
Anyway, I noticed things started to get worse again Wednesday night and hoped it was just the temporary treacle problem we get on Teesside every month, it's been especially bad tonight with speedtest showing .5meg download speeds with upload almost outstripping download. I checked my modem levels again and they're now down to -9. How, in the space of two days have my signal levels dropped so rapidly?

The engineer also said there were long standing problems on Teesside which probably won't be fixed any time soon and advised me to stop paying for 10meg and go down to 4meg.

Sirpingalot · 27-04-2007, 19:30

Ouch, just what is QAM anyway? My modem config -

Downstream Lock : Locked
Downstream Channel Id : 1
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -8.7 dBmV
Downstream SNR : 31.4 dB

deathtrap3000 · 27-04-2007, 19:34

This is my config -

Downstream Lock : Locked
Downstream Channel Id : 0
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -13.7 dBmV
Downstream SNR : 29.2 dB

Horace · 27-04-2007, 19:39

Quote:

Originally Posted by Sirpingalot

Ouch, just what is QAM anyway? My modem config -
*snip*

http://en.wikipedia.org/wiki/Quadrat...ude_modulation

If you can understand that then you're a smarter man than me. I'm just going on information I read at Chetnet regarding acceptable power levels for QAM256 vs QAM64.

yer nice one · 27-04-2007, 21:18

This is my config

Downstream Lock : Locked
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Interleave Depth : taps12increment17
Downstream Receive Power Level : -2.8 dBmV
Downstream SNR : 29.7 dB

rvspeter07 · 27-04-2007, 22:48

Quote:

Originally Posted by Horace

The engineer also said there were long standing problems on Teesside which probably won't be fixed any time soon and advised me to stop paying for 10meg and go down to 4meg.

I'm in Teesside and I drop to around 6mb minimum from around 1800-2200 and at the full 10MBit basically every other minute of the day, no problems here. I posted my power levels etc here.

Sirpingalot · 28-04-2007, 00:41

Well, they're clearly both just modulation types (we all knew that), but I don't know which is more acceptable. And if I'm honest, I just don't have the patience to be bothered to even attempt reading that...

But from what I did read higher QAM can deliever more data than lower QAM but it is less reliable...