Cable Broadband Internet Signal loss from serial RG59 cabling - RF amp recommendations?

Cable Broadband Internet Signal loss from serial RG59 cabling - RF amp recommendations?
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Cable Broadband Internet Signal loss from serial RG59 cabling - RF amp recommendations? drydem 01-20-2008
Posted by drydem on January 20, 2008, 10:20 am
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I currently have cable broadband internet from Comcast. The initial
basic installation was just a wire through the main exterior wall. I
am leasing a Scientific Atlantic DPC2100 cable modem from Comcast ( I
am getting about 4Mbps download/ 380 kbps upload currently).

My three floor townhome was built prewired for cable/TV antenna - but
the tv antenna/cable wall jacks were not installed. Recently, I
decided to use the pre existing internal (wall) wiring so I could set
up my computer upstairs with cable broad band internet connection on
the third floor. So I installed five tv antenna/cable wall sockets/
jacks. I found out that the house was serially prewired with RG59
dual shielded coaxial wire and that I had to use a 1Ghz two-way
splitter to connect each wall jack. Initially I was able to get an
excellent cable and internet signal from the first(ground/basement)
and second(main) floor wall jack; however, the third(top) floor wall
cable jacks had very poor cable signal and no internet signal. The
cable signal had apparently degraded signficantly as the length of the
wire increased and the number of splitters increased. By installing
a Radio Shack RF amp (VCR/TV/FM Variable 20db amp Catalog No 15-1113)
at the very front of this serial RG59 cable - I was able to boost the
cable signal so that all the cable channels were strong enough to view
clearly on the third floor but it completely blocked the cable
internet signal on every floor. I know that the signal loss is due to
the use of serial prewiring of RG59 and that it would have been better
had the house had prewired with parallel RG6 cables ; but I would like
to avoid ripping up the drywall and rewiring the house from the ground
up.

Is there a RF amp/splitter ( F-connector) that could boost both the
cable and internet signals?

Walter

Posted by Bill M. on January 20, 2008, 5:47 pm
On Sun, 20 Jan 2008 07:20:25 -0800 (PST), drydem

>
>I currently have cable broadband internet from Comcast. The initial
>basic installation was just a wire through the main exterior wall. I
>am leasing a Scientific Atlantic DPC2100 cable modem from Comcast ( I
>am getting about 4Mbps download/ 380 kbps upload currently).
>
>My three floor townhome was built prewired for cable/TV antenna - but
>the tv antenna/cable wall jacks were not installed. Recently, I
>decided to use the pre existing internal (wall) wiring so I could set
>up my computer upstairs with cable broad band internet connection on
>the third floor. So I installed five tv antenna/cable wall sockets/
>jacks. I found out that the house was serially prewired with RG59
>dual shielded coaxial wire and that I had to use a 1Ghz two-way
>splitter to connect each wall jack. Initially I was able to get an
>excellent cable and internet signal from the first(ground/basement)
>and second(main) floor wall jack; however, the third(top) floor wall
>cable jacks had very poor cable signal and no internet signal. The
>cable signal had apparently degraded signficantly as the length of the
>wire increased and the number of splitters increased. By installing
>a Radio Shack RF amp (VCR/TV/FM Variable 20db amp Catalog No 15-1113)
>at the very front of this serial RG59 cable - I was able to boost the
>cable signal so that all the cable channels were strong enough to view
>clearly on the third floor but it completely blocked the cable
>internet signal on every floor. I know that the signal loss is due to
>the use of serial prewiring of RG59 and that it would have been better
>had the house had prewired with parallel RG6 cables ; but I would like
>to avoid ripping up the drywall and rewiring the house from the ground
>up.
>
>Is there a RF amp/splitter ( F-connector) that could boost both the
>cable and internet signals?

Serial wiring? Ouch, what a mess of a bad idea. As you know, the best
thing would be to rewire the entire house with 'home run' cables,
preferably quad shield RG-6 or equivalent rather than RG-59. That's a
lot of work, though.

Barring that, I would add a 2-way splitter where the cable arrives at
the house. One output of the new splitter would connect back into the
house wiring and would power all of the existing TV jacks, and the
other output of the new splitter would connect to a new cable that
would run up the outside of the house to the new office. With this
plan, your new office would have two cable jacks, one for TV and one
for Internet/TV. If necessary, you could still add an RF amp to the
non-Internet side of the new splitter without significantly affecting
the cable modem.

--
Bill

Posted by $Bill on January 20, 2008, 8:54 pm
Bill M. wrote:
>
> Serial wiring? Ouch, what a mess of a bad idea. As you know, the best
> thing would be to rewire the entire house with 'home run' cables,
> preferably quad shield RG-6 or equivalent rather than RG-59. That's a
> lot of work, though.
>
> Barring that, I would add a 2-way splitter where the cable arrives at
> the house. One output of the new splitter would connect back into the
> house wiring and would power all of the existing TV jacks, and the
> other output of the new splitter would connect to a new cable that
> would run up the outside of the house to the new office. With this
> plan, your new office would have two cable jacks, one for TV and one
> for Internet/TV. If necessary, you could still add an RF amp to the
> non-Internet side of the new splitter without significantly affecting
> the cable modem.

I agree with everything except the running of the cable outside. That
would have to be a last resort. If at all possible, try to find a way
to run it inside if that's what you end up doing.

Another alternative would be to put a decent wireless router at the entry
point and going wireless to the third floor for your internet access.
That would eliminate the need for tearing up your walls or hanging wire
outside the house.


Oftentimes, you can replace parts of your run by just tying one (or even
two cables) to the end of your existing cable and pulling the new cable
through, but that can easily be defeated by staples and such that may
have been used. You could test that easily enough by just tying some
string to the end of the cable and seeing what happens if you give a bit
of a tug on the next outlet in line and see if the cable runs free.

That would allow you to at least run parallel cables along the serial
route which wouldn't be as short as home runs could be, but the RG6
would make up for the loss due to length over the RG59.

I would think any RG6 or RG11 should be great for longer runs of
non-baseband cable (dual or quad shielded only if you can afford it),
but a CM rated RG59 will handle most of your *short* haul needs with
not much less dB loss than RG6 (in your case with them all strung
together serially, that probably isn't true).

Posted by drydem on January 22, 2008, 9:53 am
> Bill M. wrote:
>
> > Serial wiring? Ouch, what a mess of a bad idea. As you know, the best
> > thing would be to rewire the entire house with 'home run' cables,
> > preferably quad shield RG-6 or equivalent rather than RG-59. That's a
> > lot of work, though.
>
> > Barring that, I would add a 2-way splitter where the cable arrives at
> > the house. One output of the new splitter would connect back into the
> > house wiring and would power all of the existing TV jacks, and the
> > other output of the new splitter would connect to a new cable that
> > would run up the outside of the house to the new office. With this
> > plan, your new office would have two cable jacks, one for TV and one
> > for Internet/TV. If necessary, you could still add an RF amp to the
> > non-Internet side of the new splitter without significantly affecting
> > the cable modem.
>
> I agree with everything except the running of the cable outside. =A0That
> would have to be a last resort. =A0If at all possible, try to find a way
> to run it inside if that's what you end up doing.
>
> Another alternative would be to put a decent wireless router at the entry
> point and going wireless to the third floor for your internet access.
> That would eliminate the need for tearing up your walls or hanging wire
> outside the house.
>
> Oftentimes, you can replace parts of your run by just tying one (or even
> two cables) to the end of your existing cable and pulling the new cable
> through, but that can easily be defeated by staples and such that may
> have been used. =A0You could test that easily enough by just tying some
> string to the end of the cable and seeing what happens if you give a bit
> of a tug on the next outlet in line and see if the cable runs free.

yes.

I thought about that - but I decided
against doing that because of the way the RG59
cable is threaded. The RG59 cable is threaded
from the roof/attic and winds through three
bedrooms (third floor) to the living room ( second
floor) and then drops down into an unfinished
basement(first/ground floor). The attic cable
was put there by the builder to accommodate
an attic TV aerial antenna since a rooftop TV
aerial antennas are banned by the HOA.
Rethreading the cable is also best done as a
two person job ( one feeding cable, one pulling
the cable). Given the limited time I have allocated
for this project - I decided that rethreading would
be best for a later project.


>
> That would allow you to at least run parallel cables along the serial
> route which wouldn't be as short as home runs could be, but the RG6
> would make up for the loss due to length over the RG59.
>
> I would think any RG6 or RG11 should be great for longer runs of
> non-baseband cable (dual or quad shielded only if you can afford it),
> but a CM rated RG59 will handle most of your *short* haul needs with
> not much less dB loss than RG6 (in your case with them all strung
> together serially, that probably isn't true).



Posted by on January 21, 2008, 1:19 am
>
> I found out that the house was serially prewired with RG59
> dual shielded coaxial wire and that I had to use a 1Ghz two-way
> splitter to connect each wall jack. Initially I was able to get an
> excellent cable and internet signal from the first(ground/basement)
> and second(main) floor wall jack; however, the third(top) floor wall
> cable jacks had very poor cable signal and no internet signal.

As others have said, the best thing would be to run a separate cable for
the modem, but you might be able to get away with your current setup by
using directional taps instead of simple splitters. A splitter sends
half the incomming signal to each outlet, so the first jack in the chain
gets 1/2 the original signal and sends 1/2 along the chain, the next
jack in line gets 1/4 of the original signal, the jack after that 1/8,
then 1/16, etc. Taps, while harder to find, split the signal unevenly
so that most of the signal is sent along the chain with only a small
amount being sent to the jack, which keeps the signal level from
diminishing so quickly as you go along the chain.

If you still need an amplifier, you must get one that has a return path
(bidirectional). Simple unidirectional amplifiers block the cable
modem's upstream transmissions, which keeps it from working.

-Larry Jones

I think we need to change the rules. -- Calvin

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