In article ,
Jerry wrote:
A question from a lay person. I'm looking for information on what kind
of CATV splitter to buy. I have Time-Warner analog CATV and don't use
any cable box. All my devices use coaxial RF cable as input. Here's my
setup...
Cable comes into my house's outside junction box into a 4-way splitter
with each output saying 7dB (whatever that means), then goes to four
rooms.
That means that the RF signal level at each output port is 7 dB below
the level being fed into the input. That's not too bad - a perfectly
lossless 4-port splitter would divide the power four ways, resulting
in an output level at each port which was 6 dB below the input level.
This splitter has 1 dB of additional loss.
Room 1: Bedroom without any TV. Coax not terminated.
Room 2: Office with cable modem and TV. Cable company used a 2-way
splitter with each output saying 3.5dB.
Again, that's not too bad - 3 dB of reduction per port (50% of the
power going each way), plus an additional .5 dB of loss in line with
each port.
This means that your TV and cable modem are seeing signal levels 10.5
dB below the level that your cable company is feeding your house.
Room 3: Bedroom with a TV.
Room 4: My main media room. Here's where I need the right coax splitter.
I currently have a 2-way splitter connected to a VCR and a TiVo. I'd
like to add a DVD recorder with a cable-ready tuner. All 3 devices would
have coaxial RF cable input.
My two questions:
1. Should I get a 4-way coax splitter with each output at 7dB and
terminate the unused output? This would leave an output free for future
expansion in Room 4. I saw such a splitter at Radio Shack. Is there a
better brand?
You could do that. You'll be wasting some of the RF power fed to that
room, into the termination resistor on the fourth port.
Or, you could daisy-chain an additional 3.5 dB splitter off of one of
the two ports on the existing two-way splitter. This approach will
give you three outputs, two of which have lower RF levels than the
third. Use the third port (the one coming out of the first splitter)
to feed whichever device seems to need the strongest signal for a
decent picture.
2. Should I terminate the cable in the unused Room 1?
Generally a good idea, for several reasons. RFI is one such reason...
unterminated ports can "leak" RF, and some of the cable-TV channels
overlap with amateur bands (e.g. 2 meter) and aircraft/public-safety
bands. Cable companies are required to [try to] keep their cable
plants leak-free, due to the interference that these cable channels
can cause.
--
Dave Platt AE6EO
Hosting the Jade Warrior home page:
http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!