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nponeccop
Asked: 2012-01-23 16:40:12 +0800 CST

How ITU G.9954 Ethernet Over Coaxial Network (EoCNA) interacts with Cable TV signal boosters?

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I didn't found the proper forum - so move the question if you find a better place for it.

We have 10 houses scattered in the area 500 meters in diameter, and have a tiny DIY CATV network providing houses with 2 analog TV channels (don't laugh it's third world).

We use cheap CATV signal boosters/line amplifiers at some intermediate houses to get the TV signal to the farthest houses.

Now we want to setup an IP network between the houses, so what is the lowest cost solution for that? We won't need more than 1 megabit, so basically speed doesn't matter.

The lowest cost solution seems to be "ethernet switches hanging on trees", but it's not reliable.

DOCSIS seems too powerful for our tiny setup, so we consider DSL (VDSL/SHDSL, also it seems there are 8-port ADSL DSLAMs for $600), EtherLoops ($160 per modem pair) and newer EoCNA standard. The EoCNA seems attractive because of reuse of our CATV cables.

The question is, if we decide to deploy ITU G.9954 Ethernet Over Coaxial Network (EoCNA), what are the requirements for our signal boosters? Do they need a special capabitity to pass the backward signal? Are there any good white papers/docs about the ITU G.9954 technology?

What else technologies can we consider, given we targeting $300 per house with up to 10 houses?

Some houses may be rather close, so we think of mixing long-range and short-range techs (e.g. wifi repeaters or plain ethernet between some houses) if that can lower the cost.

networking

2 Answers

  1. Most cable signal boosters either do not pass reverse signals, or pass them but do not amplify them (this is to avoid injecting RF noise into the cable plant).

    You need to purchase bidirectional cable amplifiers in order to ensure that the return signals make it to your head end.

    Also note that since you are already running a CATV network (based on your question) DOCSIS is probably the better choice for your deployment: It may seem like overkill, but it is a well-proven technology with a large ecosystem of hardware and software tools available to support your deployment. The initial costs will be balanced by the savings in maintenance & troubleshooting, as well as end-user hardware.

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  2. Best Answer

    From an EoCNA device documentation:

    Amplifiers often do not include EoCNA in their downstream band. In cases where this type of device is installed, it should be replaced with one that has a bypass in the EoCNA band. Bypass is done by connecting a low pass filter (LPF) with a cutoff frequency of 45MHz in parallel with the amplifier as shown in Figure 1 (a). Note that in the cases where the amplifier has amplification for both downstream (DS) and upstream (US) directions (i.e. for the return channel, as shown in Figure 1 (b)), it would have overlapping bands with the LPF used for bypass and undesired effects such as positive feedback might occur in which case the amplifier should be replaced.

    So you would just need to add bypass LPFs to your amplifier installations.

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