I am looking for some input as to the recommended levels for up and downstream to my modems.
The plants are all relativity small, serving no more than 200 doors in apartment complexes. Each plant has 60 channels of analog, 53 QAM channels as well as a Cisco uBr7246 CMTS with Mc28 cards. We are running 2 downstream channels, 104 and 106, and 8 upstream channels. We have deployed Arris 402, 502 and 602 P and G series telephony modems. We are having a problem with the MTA side of the modem dropping when it is issued a re-invite from our SIP server.
The modem spec sheet states operational range is from -15 to +15. In our plants we are running our digitals as well as our docsis channels 8 dBc.
I am of the belief that we should be designing out plant to hit the modem as close to 0 dB as possible with a return between +38 to +48 so as to not overtax the modem.
After a long conversation with our programmer, he is of the opinion that we are running our modems too hot. He spoke to an RF MBA that stated we should be hitting them right around -15 dB.
These plants are running a mix of docsis 1.1 and docsis 2.
Please help me figure this out, I believe the RF MBA has no practical knowledge of field deployment (full of shit). I am trying to get this straight before they convince the owner of the plants to redesign and implement a lower level to the modems.
If needed I am available by phone to discuss this, just drop me a private msg and I will give you a call.
Recommended modem levels?
Member #: 21663
Registered: 2/17/2003
Posted:
120
Name:
Woodybeetle
Company:
DDCESI
Occupation:
Video Idiot
Location:
Pensacola florida
Experience:
~32 years
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