Power Line Modem Carrier Frequency

It uses one of several HomePlug standards, HomePlug AV, HomePlug Green (PHY), and HomePlug AV2. More recently also IEEE 1901. The exact technology and standard used depends on the specifi product, which you did not specify: (old)

In theory, any device that complies with various HomePlug standards, should be able to talk to similar devices from different manufacturers. In reality, each manufacturer adds their proprietary enhancements to make sure that will never happen. Compatibility across different standards is also problematic.

If you mean discrete frequencies, no. There are no discrete "frequency components", whatever that means. It's all spread spectrum, where the power is spread across the available spectrum. For example, HomePlug AV goes from 1.8MHz to about 28MHz. IEEE 1901 extends this to 50 MHz. HomePlug AV2 stretches it to 86MHz. AV2 also adds MIMO which allows multiple orthogonal signals to take various paths through the house wire, which are later combined to give the higher speeds. There are also some intentional "holes" in the spectrum to protect existing services that might not appreciate broadband noise produced.

Here's an example of the radiated trash produced by a typical HomePlug AV2 system. I've run similar conducted radiation tests on other products with similar spectra.

Thanks Jeff. That's exactly the information I wanted, but didn't know the correct terminology to research it.

What is your specialty BTW?

Martin King

Note that those are radiated emissions tests, performed nowhere close to FCC requirements. However, the spectrum analyzer photos do offer a clue as to the nature and extent of the RFI problem. If you're going to do your own testing and want to do conducted radiation testing, you'll need to build or buy an LISN (line impedance stabilization network): mostly to keep OTA (over the air) sources from entering the test equipment via the power lines, and ruining the measurements.

Power line networking is just another form of BPL (broadband over power line) or PLC (power line communications) networking, which is known to radiate RFI well above limits established by the FCC. House wiring and power distribution wiring make fairly good antennas. BPL/PLC uses higher power levels to go longer distances than HomePlug, but is otherwise quite similar. Ask about BPL or power line networking in any of the ham radio forums.

Ah, my favorite topic... me.

I'm not a specialist. I'm more of a generalist. Specialization is risky as many specialties have either disappeared or become obsolete. (I'm 66.5 years old and doing a slow motion slide into retirement and possible impoverishment). In the past, I've helped design both the electronics and mechanical for marine radios (HF and VHF), direction finders, pagers, data link radios, consumer electronics, some antennas, sewage sampler, games, VoIP hardware, and some stuff I don't want to disclose. Some I've helped design, but mostly I clean up other peoples problems. I've also worked for or owned a print shop, various electronic repair businesses, and part of an avionics shop. Add some consulting on everything from doing business plan sanity checks to chain saw repair. At this time, I'm doing mostly consulting and computer repair. At any given time, I have at least two businesses running.

Now that you have mentioned it, I am particularly interested in the "stuff you don't want to disclose".

You mean like black budget hardware? No worries, you can tell us about it.

Martin King