Frequency range that can pass through the splitter is 55Mhz(?)-1GHz, usable is less
then that with roll-off at the extremes hence the additional 100Mhz spec on modern
splitters. The dBmV rating measures attenuation of power for the center-frequencies
with +8~+15dBmV being the range you want at the end of the cable for TV.
Street street drop to demarc should be more than strong enough UNTIL you start
figuring in splitters & cable lengths. This is why typically modems get installed
right after demarc location on a attenuated tap 4~10dB. The tap attenuates signal to
the modem but not the downstream signal into the residence. It's possible to still
have so much power than attenuators are needed at the end devices but bad drops, old
cable, dumb contracted installers, & just doing spits in the wrong order eats up any
margin quick.
If they've tested for FULL SPECTRUM at the furthest in connection & said "good" I'd
be asking for the definition & basis for that diagnosis. No matter what I'd be
checking the signal path from demarc on through to the DVR's RF jack to calculate how
much total loss is. Maybe a tap is the right choice vs. splitting, maybe you're not
using RG6, etc... Could even be transient (easily missed testing) or could be a
attenuation in a narrow notched range.
Visually checking over the cable path might yield insight about issues of poorly
installed or badly sequenced splits/hardware. This diagram is not for CATV but in
concept given CATV drop /w strength @ n dB's the diagram correctly illustrates the
effects of splits:
http://www.channelvision.com/files/guides/diagramsLayouts.pdf
My experience is based on CATV modems, YMMV. BTW I spent almost a month arguing I had
a bad drop that "tested" good. In the end it took advanced techs & time to realize
some installer had baluns in-line & the cable was not linear. My modem told me so but
the cable co did not want to hear it. There is likely a rant in our archives here
from 2004. =)
Bino Gopal wrote:
Hmm, ok on that note, what's the 1 Ghz for the splitter refer to-or the
4/0db unbalanced thing? I've got TW Cable at home and have it split 4 ways
(this is after it's split once to the bedroom and living room from the
junction box at the back of the apt) but the cable techs have tested the
signal strength and said it's actually still moderately high-even after the
4-way split-so I should be good...
I've just got a simple 4-way splitter and if there's a better one I can get
(or an amplifier or something else that can clean/improve the signal) I'd
definitely consider it! I just upgraded my TivoHD to a 1GB HD and I'm
getting occasional drops and I'm thinking it's the signal now (I thought it
was the hard drive before, but it's still happening even after I replaced
the hard drive, so now it's pointing to something else) so rather than have
the techs come out again and say it's fine, I was wondering on what I could
do myself.
Anyone got any pointers on what to look for or where?
BINO
-----Original Message-----
From: hardware-boun...@hardwaregroup.com
[mailto:hardware-boun...@hardwaregroup.com] On Behalf Of maccrawj
Sent: Monday, April 06, 2009 7:45 AM
To: hardware@hardwaregroup.com
Subject: Re: [H] Project Falling by the wayside....
Yes, 1GHz and it also might have to be an unbalanced 4/0db if signal is
weak.
Steve Tomporowski wrote:
Splitting the Video: One thing I haven't asked about on the list.
Wanted to split the cable line that goes to the modem so that I can
watch TV on one of the boxes (hauppauge Analog/Digital Card). The
splitter I tried to use resulted in no internet and an unhappy modem. I
think I need a 1Ghz splitter. I doubt that one was.
