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Anonguy

@cox.net
reply to jsmiddleton4

Re: [AZ] Amp vs no Amp readings

You definitely do NOT teed the amp with those levels. -6 is fine!

jsmiddleton4

join:2003-11-13
Glendale, AZ
I'm thinking not as well. One of our forum friendly Cox guys is on it as well. Will be back with him on Monday.

If I understand what I'm seeing correctly, again IF, the problem is the SNR readings. Dropping below 40 not so good.

If....

Hoss
Sauters A Walrus

join:2000-10-05
Tulsa, OK
said by jsmiddleton4:

I'm thinking not as well. One of our forum friendly Cox guys is on it as well. Will be back with him on Monday.

If I understand what I'm seeing correctly, again IF, the problem is the SNR readings. Dropping below 40 not so good.

If....

What?

40 is a GREAT SNR (I get it consistently), but anything above 36, especially when channel bonding, is within spec.

jsmiddleton4

join:2003-11-13
Glendale, AZ
I did say If Hoss.

I'm passing along what the tech told me. The amp was needed due to the SNR.

He wanted it at 40 or above that when in the readings get down in the 30's its problematic.

But even at that with the amp the SNR numbers don't change all that much.

I of course do not know what his testing equipment showed.

jsmiddleton4

join:2003-11-13
Glendale, AZ
reply to Hoss
This from the FAQ here.

DOCSIS 3.0 modems:

Downstream power level (Receive): -15dbmV to +15dbmV
A value of -10 or worse indicates a poor downstream signal path. A tech would aim for a value close to the optimal 0 dBmV, but a good cable modem should be capable of working within the broader range of -10 to +10 dBmV, provided the downstream Signal to Noise Ratio remains good enough. Additionally all downstream channels should be within a +/-2db window with respect to each other.

Upstream (Transmit): 40-52 dBmV. A value within the range +40 to +52 dBmV is within spec with the low to mid 40's the most common. If the cable modem is going offline, and the upstream signal strength is at or above +52dBmV, then a poor upstream path is probably the problem.

Carrier/Noise Ratio: 35 db and above The downstream Signal to Noise Ratio must be 35 dB or higher on each channel. The lower ratio the more noise and the poorer the performance. The Cable Modem will have to keep requesting retransmissions of packets with uncorrectable errors.

Hoss
Sauters A Walrus

join:2000-10-05
Tulsa, OK
reply to jsmiddleton4
said by jsmiddleton4:

I did say If Hoss.

I'm passing along what the tech told me. The amp was needed due to the SNR.

He wanted it at 40 or above that when in the readings get down in the 30's its problematic.

But even at that with the amp the SNR numbers don't change all that much.

I of course do not know what his testing equipment showed.

The last tech I spoke with last year told me that 40s usually only occur when the line condition is a 10. Not common. My line condition: a 10. I suspect yours is, or is close. My power levels on the DS are typically about -2.

jsmiddleton4

join:2003-11-13
Glendale, AZ

1 edit
The tech was a residential install guy. It was the install for the business side for work at home.

I don't know if the business side for stability reasons has a higher bar?

10 being good like the movie Ten? Not sure what 10 means as these figures are all ratios correct? So is 10 some quotient factor or just a descriptor?

Edit: Sorry, tech was NOT a residential install guy. Left the "not" out.