ONT power supplies are really noisy
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On Thu, Feb 23, 2017 at 3:56 PM -0500, "Greg Troxel" <gdt@lexort.com> wrote:
Aaron Kreider writes:
> I'm thinking of switching from Verizon DSL to Comcast FIOS for faster
> and more reliable internet.
>
> I'm hoping that the FIOS will be cleaner in terms of RFI. What
> possible sources of RFI are there from FIOS? Do they use signal
> boosters that put out RFI? I'm guessing the router will be the
> biggest source and that chokes on that will alleviate most of it.
>
> I'm in Philadelphia, PA and we already have FIOS lines on our street -
> so perhaps they already have the signal boosters installed.
As others said, FiOS is a Verizon trademark for what used to be called
Fiber To the Premises (FTTP).
The way it works is similar to Hybrid Fiber Coax cable systems, where
there is fiber to boxes on poles and then coax, except that with FiOS
the fiber goes all the way to your house and you have your own Optical
Networking Terminal (ONT).
There is a cable of fibers from the CO to the neighborhoods. Each
strand from the CO goes into a 32-1 passive splitter, and then there are
drop cables from houses to a "pod" hanging near a pole and connecting to
one of the 32 split fibers. The great thing about FiOS is that there is
no electronics outside. There is the ONT at your house, and stuff at
the CO, and everything in between is fiber, splices, and the 32-1
passive splitter. (off topic: so if you give your ONT power during a
failure, it will still work, internet and phone, unlike cable which
around here fails after an hour. I don't know anything about TV.)
They will want you to use MoCa which is ethernet over 75-ohn coax from
the ONT, but you can connect that to a router close by, and choke the
cable if you need to. And of course routers have cheap SMPS that need
cleaning up.
I've had FiOS for 10 years. I've had one actual problem, water/bugs in
outdoor splice box (that most don't have; my run is long), and a few
several hour flakes of Internet service that resolved without me
calling. Overall an A+ for reliability for home Internet.
As for RFI, I have never noticed any. There are no long wires not under
your control; the incoming cable is really just a fiber strand with a
lot of physical protection. Then there are POTS lines, coax for TV, and
sometimes RJ45 for wired ethernet (which I use). I have a pretty quiet
location and not too much modern junk plugged in (e.g., seeing S1-S2 on
18 MHz right now, and two S4 spikes in a 50 kHz span). Overall it's
good enough that I haven't gotten around to the full power-off and hunt
game (but I should anyway). So if you already have cleaned up massively
to have zero issues, you might notice it. If you are semi-normal,
and/or you live in the city, you probably won't. That's assuming the
ONT power supply you get is OK. Mine is at least mostly ok and might be
really good; it's from 2006.
Overall, my unsubstantiated opinion is that telco gear like the ONT is
much more likely to be designed correctly than cable company stuff. But
the router/wifi boxes are likely similar. The good news is you can
change it out to a quiet one if you have to.
73 de n1dam
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