Mailing List Archive: [OT] coax splitting?

[OT] coax splitting?

Aug 1, 2003, 1:04 AM

Post #1 of 6 (1400 views)

Hello,

I have coax running from the wall, and 2 or 3 tuners I want to connect. I'm
looking for recommendations as to doing this. In the same house I have
another TV and a cable modem, so I'm worried I need some sort of amplifier
to have 5 devices connected and still get a good signal in each of them. I'm
pretty clueless about this stuff.

Both tuners can take either coax or S-video, but the TV's S-video input is
needed for input from the myth box, so if I want to record 2 w/myth and
watch 1 wo/myth, the TV needs coax in. Let me try to draw a picture, in
which data travels down and to the right unless otherwise noted:

CURRENT

+------------+ coax +------------+
|box in attic|--------|secondary TV|
+------------+ +------------+
c| c\
o| o\
a| a\
x| x\
+-----------+ +------------+ myth +--------+ Sv +----------+
|cable modem| |myth tuner 1|------|myth out|------|primary TV|
+-----------+ +------------+ +--------+ +----------+

WANTED

+------------+ coax +------------+
|box in attic|--------|secondary TV|
+------------+ +------------+
c| c\
o| o\
a| a\
x| x\
+-----------+ +--------------+
|cable modem| |mystery device|
+-----------+ +--------------+
?/ ?| c\
?/ ?| o\
?/ ?| a\
?/ ?| x\
+------------+ +------------+ +----------+
|myth tuner 1| |myth tuner 2| |primary TV|
+------------+ +------------+ +----------+
m\ m| /
y\ y| -->-->
t\ t| / Sv
h\ h| /
+--------+
|myth out|
+--------+

So what I'm inquiring about is the mystery device (or cable) and the two
mystery connections, which can either be coax or S-video. The coax running
from the mystery device to the primary TV would be nice, but I can live
without it.

FWIW, I have basic (non-digital) cable from Time Warner in the US. All the
myth stuff is on one box next to the TV.

Thanks in advance,
--
Omer Shenker http://omershenker.net/

Re: [OT] coax splitting? [ In reply to ]

webmaster at dddane

Aug 1, 2003, 10:52 AM

Post #2 of 6 (1374 views)

Permalink

> I have coax running from the wall, and 2 or 3 tuners I want to connect.
I'm
> looking for recommendations as to doing this. In the same house I have

buy a good quality splitter... i think its better to have as few splitters
(with longer cables coming out of that perhaps as a result) versus many
splitters and shorter cables out?

you can buy a 10 dB amplifier just about anywhere (best buy, ebay, circuit
city, wal-mart)... I was at home depot last weekend and noticed they had a
25 dB amplifier... Just a note, I tried putting an amplifier on my line and
it caused the cable modem to not work, you have to amplify only the cable
going to the TV.... though I'm not sure I would say it made any difference
in my instance anyway. amplifiers are for cable lenght issues...if you
have a bad signal to start with it probably wont do anything. i'd say try
it without it first... or buy it maybe and return it a day later if it
doesnt do anything?
-dane

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Re: [OT] coax splitting? [ In reply to ]

mythtv at matter

Aug 1, 2003, 10:59 AM

Post #3 of 6 (1376 views)

Permalink

Not sure if this will answer your question, but I'm finding this to be
helpful for general cable wiring. I am also trying to shore up the cable
in my house to get better signals.

http://www.dslreports.com/faq/cabletech/all

Larry

> Hello,
>
> I have coax running from the wall, and 2 or 3 tuners I want to connect.
> I'm
> looking for recommendations as to doing this. In the same house I have
> another TV and a cable modem, so I'm worried I need some sort of amplifier
> to have 5 devices connected and still get a good signal in each of them.
> I'm
> pretty clueless about this stuff.
>
> Both tuners can take either coax or S-video, but the TV's S-video input is
> needed for input from the myth box, so if I want to record 2 w/myth and
> watch 1 wo/myth, the TV needs coax in. Let me try to draw a picture, in
> which data travels down and to the right unless otherwise noted:
>
> CURRENT
>
> +------------+ coax +------------+
> |box in attic|--------|secondary TV|
> +------------+ +------------+
> c| c\
> o| o\
> a| a\
> x| x\
> +-----------+ +------------+ myth +--------+ Sv +----------+
> |cable modem| |myth tuner 1|------|myth out|------|primary TV|
> +-----------+ +------------+ +--------+ +----------+
>
> WANTED
>
> +------------+ coax +------------+
> |box in attic|--------|secondary TV|
> +------------+ +------------+
> c| c\
> o| o\
> a| a\
> x| x\
> +-----------+ +--------------+
> |cable modem| |mystery device|
> +-----------+ +--------------+
> ?/ ?| c\
> ?/ ?| o\
> ?/ ?| a\
> ?/ ?| x\
> +------------+ +------------+ +----------+
> |myth tuner 1| |myth tuner 2| |primary TV|
> +------------+ +------------+ +----------+
> m\ m| /
> y\ y| -->-->
> t\ t| / Sv
> h\ h| /
> +--------+
> |myth out|
> +--------+
>
> So what I'm inquiring about is the mystery device (or cable) and the two
> mystery connections, which can either be coax or S-video. The coax running
> from the mystery device to the primary TV would be nice, but I can live
> without it.
>
> FWIW, I have basic (non-digital) cable from Time Warner in the US. All the
> myth stuff is on one box next to the TV.
>
> Thanks in advance,
> --
> Omer Shenker http://omershenker.net/
>
>
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

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Re: [OT] coax splitting? [ In reply to ]

geekofalltrades at shaw

Aug 1, 2003, 7:21 PM

Post #4 of 6 (1393 views)

Permalink

Omer Shenker wrote:

>Hello,
>
>I have coax running from the wall, and 2 or 3 tuners I want to connect. I'm
>looking for recommendations as to doing this. In the same house I have
>another TV and a cable modem, so I'm worried I need some sort of amplifier
>to have 5 devices connected and still get a good signal in each of them. I'm
>pretty clueless about this stuff.
>
>Both tuners can take either coax or S-video, but the TV's S-video input is
>needed for input from the myth box, so if I want to record 2 w/myth and
>watch 1 wo/myth, the TV needs coax in. Let me try to draw a picture, in
>which data travels down and to the right unless otherwise noted:
>
>CURRENT
>
>+------------+ coax +------------+
>|box in attic|--------|secondary TV|
>+------------+ +------------+
> c| c\
> o| o\
> a| a\
> x| x\
>+-----------+ +------------+ myth +--------+ Sv +----------+
>|cable modem| |myth tuner 1|------|myth out|------|primary TV|
>+-----------+ +------------+ +--------+ +----------+
>
>WANTED
>
>+------------+ coax +------------+
>|box in attic|--------|secondary TV|
>+------------+ +------------+
> c| c\
> o| o\
> a| a\
> x| x\
>+-----------+ +--------------+
>|cable modem| |mystery device|
>+-----------+ +--------------+
> ?/ ?| c\
> ?/ ?| o\
> ?/ ?| a\
> ?/ ?| x\
>+------------+ +------------+ +----------+
>|myth tuner 1| |myth tuner 2| |primary TV|
>+------------+ +------------+ +----------+
> m\ m| /
> y\ y| -->-->
> t\ t| / Sv
> h\ h| /
> +--------+
> |myth out|
> +--------+
>
>So what I'm inquiring about is the mystery device (or cable) and the two
>mystery connections, which can either be coax or S-video. The coax running
>from the mystery device to the primary TV would be nice, but I can live
>without it.
>
>FWIW, I have basic (non-digital) cable from Time Warner in the US. All the
>myth stuff is on one box next to the TV.
>
>Thanks in advance,
>
>
>------------------------------------------------------------------------
>

Hi.

You're going to have a tough go of it there. I work for a cable company
here in B.C. (yes Harold that company) and the standard that most cable
companies try to achieve is to get 10db of signal to your house (box in
attic here i guess) In reality I have seen anywhere from -24 db (noise
floor) to 18 db. First thing to remember is that db is a log scale - ie
2 db is 10x more than 1 db. Now the first 3 way split will drop you 5.5
db. per leg, to 4.5 db of usable signal. Next split is the mystery
device which is also a 3 way splitter (if going passive) (again a 5.5
db drop) which will get you down to -1 db. While the ideal is to get 0
db to the side of the tuner/tv, I have seen good picture at ~2-3 db (It
is here that the quality of the tv becomes apparent). So at this point
you could still have no problems given 1) a good tuner card 2) 10 db
at the side of the house 3) perfect connections to your tuners - ie rg6
cable and good (read solid one piece crimped on) connectors and premium
splitters. Any less and you will have problems. Basic cable is usually
set low in the frequency range so should have less roll-off and
therefore better signal than premium. You will notice poor signal by a)
noise - snow b) banding c) poor reception in the higher channels (ie
above ~45) Best of luck.
Your cable company should be responsive to your needs dependant on the
number of outlets you are paying for -ie we want to keep you happy but
if you're ripping us off..... - best bet is to buy an amp and hope it
doesn't screw up you or your neighbours cable modems. Where i work
homeowner amps are grounds for immediate disconnection as they can bring
down a whole node. Remember you now send crap back to us.

Best of luck.

./gary

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Re: [OT] coax splitting? [ In reply to ]

jmorris at beau

Aug 1, 2003, 9:46 PM

Post #5 of 6 (1373 views)

Permalink

On Fri, 1 Aug 2003, Gary Balliet wrote:

> Your cable company should be responsive to your needs dependant on the
> number of outlets you are paying for -ie we want to keep you happy but
> if you're ripping us off..... - best bet is to buy an amp and hope it
> doesn't screw up you or your neighbours cable modems. Where i work
> homeowner amps are grounds for immediate disconnection as they can bring
> down a whole node. Remember you now send crap back to us.

Someone in the business should know that Radio Shack sells amps specially
designed to preserve the bidirectional nature of digital cable. Yea they
will rip you a new one at $49.95 for a fourway amplified splitter, but if
you gotta have one. I was lucky and got away with a passive splitter.

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F003%5F010%5F001%5F000&product%5Fid=15%2D1197

And if that URL gets mangled, lookup part #15-1197. And be sure to carry
the number with you because as everyone knows about the typical Radio
Shack, "You have questions, we have blank stares."

--
John M. http://www.beau.org/~jmorris This post is 100% M$ Free!
Geekcode 3.1:GCS C+++ UL++++$ P++ L+++ W++ w--- Y++ b++ 5+++ R tv- e* r

Re: [OT] coax splitting? [ In reply to ]

bstoneaz at cox

Aug 3, 2003, 2:30 PM

Post #6 of 6 (1382 views)

Permalink

based on your bottom picture you only would have three drops off the coax
line so there shouldn't be a problem. as long as your mystery device isn't
passive, you only have three devices tapping the cable feed and that should
be ok.

with regards to boosters, do not put one on before your cable modem unless
your cable company oks it.

>
> > Hello,
> >
> > I have coax running from the wall, and 2 or 3 tuners I want to connect.
> > I'm
> > looking for recommendations as to doing this. In the same house I have
> > another TV and a cable modem, so I'm worried I need some sort of
amplifier
> > to have 5 devices connected and still get a good signal in each of them.
> > I'm
> > pretty clueless about this stuff.
> >
> > Both tuners can take either coax or S-video, but the TV's S-video input
is
> > needed for input from the myth box, so if I want to record 2 w/myth and
> > watch 1 wo/myth, the TV needs coax in. Let me try to draw a picture, in
> > which data travels down and to the right unless otherwise noted:
> >
> > CURRENT
> >
> > +------------+ coax +------------+
> > |box in attic|--------|secondary TV|
> > +------------+ +------------+
> > c| c\
> > o| o\
> > a| a\
> > x| x\
> > +-----------+ +------------+ myth +--------+ Sv +----------+
> > |cable modem| |myth tuner 1|------|myth out|------|primary TV|
> > +-----------+ +------------+ +--------+ +----------+
> >
> > WANTED
> >
> > +------------+ coax +------------+
> > |box in attic|--------|secondary TV|
> > +------------+ +------------+
> > c| c\
> > o| o\
> > a| a\
> > x| x\
> > +-----------+ +--------------+
> > |cable modem| |mystery device|
> > +-----------+ +--------------+
> > ?/ ?| c\
> > ?/ ?| o\
> > ?/ ?| a\
> > ?/ ?| x\
> > +------------+ +------------+ +----------+
> > |myth tuner 1| |myth tuner 2| |primary TV|
> > +------------+ +------------+ +----------+
> > m\ m| /
> > y\ y| -->-->
> > t\ t| / Sv
> > h\ h| /
> > +--------+
> > |myth out|
> > +--------+
> >

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