28 TV Cable System Wiring( Splitters , Amps, Etc)

chopperystyle

New User
Location
GA
Hello,

We just completed installation of 28 TVs on a job. Originally we thought all we had to do was run coax rg6 quad home runs to the dmarc but we just found out that the cable company will not be supplying splitters, amplifiers, etc.

They simply want to run one cable line to the system we already have wired up.

Im looking for some help to properly configure this. I understand the basics of signal loss from splitters. And gain from amps.


Can someone suggest the correct combination of splitters and amps to feed 28 TVs. The cable company will be supplying a analog signal that will use the tuners built into the TVs. There is no HD or need for a two way signal.

Im thinking of using a Holland HDA-1000 amplifier in this system. It has up to 30db of gain.


Im looking for something like this.


Demarc - Amplifier- Two way splitter- Eight Way splitter connected to each two way output, etc. etc.

Thanks in advance.
 

Henley

Member
Location
Chesapeake Bay
You don't want to use ALL Splitters. The key is to maintain a balanced signal level to each set. You want to use various size "Taps", which
have a feed thru loss of about .5 db, and different level attenuation based on need. Too much signal can be bad as well, so Ideally depending on
cable runs you would only use 1 or 2 splitters and the rest should be Taps.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Originally we thought all we had to do was run coax rg6 quad home runs to the dmarc but we just found out that the cable company will not be supplying splitters, amplifiers, etc.
Ok, bad enough they won't be supplying equipment but how about the morons at least designing it and specing for you? Is this a (big) private house or some kind of commercial installation? If it's the latter I would think the revenue from 28 customers should be incentive enough to move this along.

CATV is not the kind of thing that you can just throw together even if you do know gain and loses. You need to have test equipment that only the cable company techs have because now it's all automated and specific to their system. You not only have downstream signals to contend with, you also have reverse signals from the modems and cable boxes.

If you will be the installer that's fine but an engineer from the cable company needs to be in charge.

-Hal
 

egnlsn

Senior Member
Location
Herriman, UT
Occupation
A/V/Security Technician
What is the layout of the building and where the TVs are? What are the distances from the closet to the TVs, especially the furthest?

The HDA-1000 is a very good distribution amp -- I've used it before.

It would be best to have a properly designed system utilizing taps, as previously posted, but if the layout would support it, your thoughts may suffice.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The very first thing that I would ask is what signal level the cable company will be providing. They often have a 10db or greater range that they can set at their tap from the main cable to deal with users with varying numbers of TVs using passive splitters.
Then design your amplifying system around the highest signal level the company will give you. That will minimize noise levels and other potential problems.
As long as you do not exceed the input maximum of the amplifier(s), you want to put the amp first in line on the input from the cable.
In addition to minimizing the number of amps you need to use, this gives you the best possible noise margin at the tuner or other device.
 

Rampage_Rick

Senior Member
You don't want to use ALL Splitters. The key is to maintain a balanced signal level to each set.
Depends how it's wired. If all the cables are homerun and reasonably equal in length, then splitters are the way to go. Taps are normally used when you're branching off at various points along a main cable.

I did work on a ~110 room hotel. From the main amplifier there were taps on each floor which fed into 2-way splitters which fed into 8-way splitters which fed into 2-way splitters between adjoining rooms. Net loss after the tap would be 17.5 dB not accounting for cable loss.
32 outputs = 2^5
-3.5dB x 5= -17.5dB

I have a Visio diagram of that mess somewhere. The distribution rack is way more complex than the room feeds. They had a half-dozen cable modems throughout the property, several TC600 QAM > Analog transcoders for the public TV channels, plus 20 channel modulators for the in-house PPV and information channels.

My grandparents' house was wired with daisy-chained taps back in the '60s. Made it real interesting when the analog cable switched to 100% digital and the installer started checking levels, especially since those taps were only spec'd to 500 MHz. I ended up re-pulling most of the outlets with RG6 homeruns.
 
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