On 01/29/2015 09:07 PM, NOPE9 YES wrote:
> #1 Cable based internet went down.
>          Internet modem showed no connection.
> ( windy outside =85. nothing apparent inside )
>
> #2  Cable TV was working fine.

My opinion, cable TV is more tolerant of low quality signal.

> #3 Cable internet modem connected
> when all splitters were removed.  This
> meant no cable TV was available.

Sounds like a signal quality problem ...

> #5  Nothing appears to have changed.
> Cannot use splitters.
>
> #6  Logged into modem.  It reports
> SNR of 32dB to 41dB on bonded channels.
> dBmV of -0.1 to -0.6 on bonded channels

.... not a snr problem.

> #7  add splitters of various types
> SNR drops to 24dB  with 8 port splitter.
> SNR drops to 30db with 2 port splitter.
> ( Splitters are rated to at least 1000MHz )
> No joy when splitters are installed .

With each split there is a 3db (halved) power drop

        /-----------------[ n - 3.5db - 3.5db ]-
-[ n ]-+               /-[ n - 3.5db ]---------
        \-[ n - 3.5db ]-+
                        \-[ n - 3.5db - 3.5db ]-

I also think that adding an amp is probably not going to help unless it's
just a week signal. If its a bad signal, you'll get an amped bad signal.

Have Comcast come in and look at the signal at the ground block. Check
that the ground is connected and good at the ground block. Check your
cables from the ground block in. Any that are old, replace. If water
gets in then the signal quality will drop.

My service drop constantly needs replacing. Any 'inside' wiring is your
responsibility.

--=20
Linux Home Automation         Neil Cherry       ncherry@linuxha.com
http://www.linuxha.com/                         Main site
http://linuxha.blogspot.com/                    My HA Blog
Author of:    	Linux Smart Homes For Dummies
--=20
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