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A number of ham radio bands became unusuable due to interference over the years.
by blattimwind 9y ago
A number of ham radio bands became unusuable due to interference over the years.
- LeoPanthera 9y agoNotably, powerline ethernet destroys nearly the entire HF range, from 3 to 30MHz. This isn't just bad for radio hams, it ruins shortwave and some AM radio too.
- vvanders 9y agoThe hell? (just checked youtube and you're right.) How did that ever make it past FCC certification? I understand unintentional QRM from cheap things but that is something that's spec'd out.
- jstanley 9y agoFWIW, I use powerline Ethernet and I can pick up HF just fine.
- kakarot 9y agoThe issue is that as you and others use powerline ethernet, you leak electromagnetic interference patterns back into the powerlines. This buildup of interference from multiple homes creates problems around your area, even if you don't notice it yourself.
- Dylan16807 9y agoSo if users had a small low-pass filter installed at their fuse box it wouldn't be a problem?
- revelation 9y agoA low pass filter that can pass 50 kW isn't exactly a trivial device or small in any sense of the word.
- Dylan16807 9y agoLow pass filters don't have the power go through them. It's a capacitor going across the power supply, with a resistor for damping.
- vvanders 9y agoExcept unless you have some sort of an impedance follower you'll probably just end up attenuating your powerline networking to the point of not working.
- Dylan16807 9y agoMost of the useful signal in the system is going directly from one circuit to another. The signal headed out toward the power meter is mostly dead, and you might even improve the networking by getting rid of those extra echoes. Unless I'm mistaken?
- kakarot 9y agoOnly one way to find out... and I would love to hear about your results :)
- vvanders 9y agoI'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.