Hacker News new | ask | show | jobs
by vvanders 3146 days ago
I'd be really surprised if it works that way. I'm not a power systems engineer but I've worked a fair bit on the low voltage side of things.

My guess is that the connection to your house to the service wires in incredibly low impedance, otherwise you'd see all sorts of voltage sags when you used a large appliance with an inductive load(or power tool). So any change large enough to affect the service line is going to go straight into your house. Circuits aren't directional(unless you have a diode or voltage/impedance follower) hence why it would impact the quality of power-line networking.

Additionally any sort of low pass filter(RC, LC or RLC) involves putting a inductor(P) or resistor(R) in series with the circuit(AKA your transmission wires) which isn't simple or cheap.
1 comments
Dylan16807 3146 days ago
The impedance going to all your neighbors is pretty low too, but I don't think the system relies on signals going out that far and echoing back. High frequencies have more of a transmission line model, which is pretty directional. There's free impedance everywhere.

My understanding is that you mostly care about the minor reflections caused by wire junctions in a system like this, and that line headed outside is more or less a signal sink no matter what. It's possible a capacitor would need to be a bit further away than directly at the breaker box, but by the time you reach the pole I'm reasonably confident that absorbing the entire signal with $.50 of components and no inductor would be fine.

link
vvanders 3146 days ago
So, let's say that even what you're proposing is correct(which I'm pretty dubious about).

Is your house longer than 32ft/64ft? Those lengths are halfwave on 20m/40m and make a great radiator. For reference all I need is 5w to get out ~400mi so I'm sure these things are kicking off a ton of RF on those frequencies.

Fundamentally if you have an unshielded wire and you're driving these frequencies across it you're going to see RFI along those frequences(along with the harmonics).

link
Dylan16807 3146 days ago
Well I have no idea about that part, you'll have to take it up with https://news.ycombinator.com/item?id=15648310
link
kakarot 3146 days ago
Well I think it's a multifaceted issue, but I am not educated on how your home itself contributes to the radiation profile so I left that bit of speculation out.
link