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Discussion Starter · #1 ·
I use several Ch Plus DA-550BID amps to distribute cable and modulated signal throughout the house- I use a low pass filter on the cable feed so the modulators work. Trouble is, I cannot get the cable modem to work through the amp (it is bi-directional): I suspect the low pass filter is the culprit. I can use a splitter at the cable feed and the modem works OK, but then I am down 3.5db to feed my amps, and I can see the difference. any ideas?
 

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The DOCSIS standard allows the cable company to put the up stream and downstream almost anywhere they want.

I don't know how this would work, but you might want to try


Cable Comp --> Amp --> Spliter --> Low Pass --> Combiner --> Amp --> House

&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp-->Cable Modem
 

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At least with my setup using [email protected], the cable modem will NOT work with the low pass filter in the path. I had to use a splitter in my wiring closet right before I feed the modulator/distribution amp and put the filter on that side of the splitter. The other side goes directly to the cable modem. If you have a weak cable signal you may be able to have the cable company put a smaller value attenuator at the distribution box (little green box in ground). They did this at my house and also put in a new run of RG-11 because of the length of the run. Good luck.


Jay
 

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Quote:
Originally posted by jerndl
At least with my setup using [email protected], the cable modem will NOT work with the low pass filter in the path. I had to use a splitter in my wiring closet right before I feed the modulator/distribution amp and put the filter on that side of the splitter. The other side goes directly to the cable modem. If you have a weak cable signal you may be able to have the cable company put a smaller value attenuator at the distribution box (little green box in ground). They did this at my house and also put in a new run of RG-11 because of the length of the run. Good luck.


Jay
That's a good point to know in advance, as I plan on having a similar setup. If I could expand this idea of cable modems a little further, I have a networking question. I'll have distributed data ports (RJ45) throughout the home. If I have the cable modem in the wiring closet with the data distribution patch panel, what additional equipment will I need to plug a laptop into any port in the house and connect to the net. Also, can more than one PC do this at a time?


I figure the least I'll need is a router and a 10/100 hub? Is this correct?
 

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Discussion Starter · #5 ·
Thanks to all- I will add a 15db bidirectional amp at the cable feed, then a two way splitter to feed cable modem and distribution system via low pass filter


Dealing with [email protected] is a hit or miss deal: recently I have been having a lot of cable modem outages( cable tv still OK)so Comcast changed the modem- they said the old Motorola cyber surfer had been recalled years ago (but never told me)--still had outages- they came back and took out a 10db tap that should have been removed when modems were switched


Robertmee- I use a 10/100 hub and have cat5 jacks throughout the house: you can use a router or pay for additional IP addresses- in either case you can have more than one computer operating in the house- you can use Netmail to check your email from remote computers


when [email protected] works, it works very well- when it goes out you have problems- the people you call for tech support are... well you get the idea (the techs who come out on the trucks are very good)
 

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I have successfully used a cable amp before the splitter and then went to the TV homeruns and the Comcast @home modem without problems, so long as you use a return path 1 gHz amp. You can then use notch filters at the TV locations and everything will be fine.

There is another way that you can approach this. Since the cable company's standard proceedure is to take the incoming cable and put it thru a tap first, and then go out to the splitter (s) for the cable TV. This in effect, passes the strongest cable signal to the modem, and whatever level is left over is routed to the TV locations. There is something else that you can request. Tell the cable company that the only way you will take the cable modem is if they bring in a separate cable feed just for the modem. They don't want to do this, but if you insist upon it from the start, they can be coerced into doing it that way.
 

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Discussion Starter · #8 ·
Mr.Hookup--I would love to get a second drop but they just do not want to hear about it! I am at the end of a long street and there are no extra ports on the pole- it would take an act of Congress...


I got a Sencore 754D- same as what installers use, and I got a tap with one port 0, other port -6db: I put the modem on the -6db port and it works- this allows more signal for TV distribution- I am getting the 15db amp today but am thinking I may have too much signal ( the channel plus amps could be overloaded) but now that I have the meter I can balance everything.


one thing I saw right away is the modulator signals are 7db higher than cable signal- that is easy to correct


so this weekend I will install the amp and check signal levels


I also saw hum level of 2.7%- I think industry level is 1% on cable signal: the tech offered to call in a line tech which I may do



Mark
 

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Discussion Starter · #9 ·
still having trouble- cable modem drops out after a day or 2 when going thru bi-directional amp- cable TV signal still good, and when I connect cable direct to modem, it works fine


I bought the Sencore- have good signal levels (approx +10db) and everything else works fine


HELP!
 
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