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Old 24-03-2005, 17:29   #1
tim
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Join Date: Mar 2005
Posts: 16
tim is an unknown quantity at this point
Power levels & attenuators

I used the info here http://homepage.ntlworld.com/robin....ips/signal.html to do some checking.

This is what I got:

Code:
Frequency 	 402750000 Hz Locked
Signal to Noise Ratio 	31 dB
QAM 	64
Network Access Control Object 	ON
Power Level 	-15 dBmV

Upstream 	Value
Channel ID 	1
Frequency 	33584000 Hz Ranged
Ranging Service ID 	1573
Symbol Rate 	2.560 Msym/s
Power Level 	44 dBmV

Software Version: SB4100-4.0.6-SCM-NOSHELL
Hardware Version: 0
MIB Version: II
GUI Version: 1.0
VxWorks Version: 5.3
The downstream power level seems on the low side.
I then remembered that there a 2 attenuators between the cable feed and my SACM (SB4100).
They are 3DB and 10DB. I removed them both to see what the results would be.

This what I got:

Code:
Frequency 	 402750000 Hz Locked
Signal to Noise Ratio 	35 dB
QAM 	64
Network Access Control Object 	ON
Power Level 	-3 dBmV

Upstream 	Value
Channel ID 	1
Frequency 	33584000 Hz Ranged
Ranging Service ID 	1573
Symbol Rate 	2.560 Msym/s
Power Level 	29 dBmV
I just need to check with the knowledgable here whether I have done the right thing.

Thanks
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