[Lowfer] HomePlug System Warning

[Ralph Hartwell]

> New to me but ominously sounding for rx-ing is HomePlug systems.
Here's
> an account from a VK who seems concerned. U.S. next? [or are we
> exporting it?  ;-]
>
> Oh, for HiFERs, notice the 13 MHz item.

This has been around for several years.  You can go to Radio Shack and
but it right now.  It's in this years catalog.

Before everyone gets too worked up about this, remember that these are
Part 15 devices, and have some pretty tough restrictions.

Along that line, consider the new RF-driven light bulbs, available at
your neighborhood home supply store.  These beasties generate upwards of
30 WATTS of RF energy.  My wife purchased a couple of these
accidentally - she thought she was buying standard replacement
fluorescent table lamp bulbs - and I decided to test them.  The result
was quite interesting.  Using my BC-348 RX and a 10 foot antenna, I
could not pick up the signal from the lamps if I was more than about 10
feet from the lamp.  I has previously thought that these things would
generate horrible RFI, but apparently this is not so, at least for the
samples I have here.  Again, these are Part 15 devices.

Back to the HomePlug problem, that these devices are designed to feed
all of their RF signal into the power line, using the power line as a
balanced transmission line.  Hence, there should be minimal unwanted
radiation in most cases.  Such things as surge suppressors also serve to
reduce the signal level on the power lines in the house. (In my house, I
have so many surge suppressers connected that even the common-as-dirt
X-10 modules only work intermittently.)

Every home is connected to a mains transformer providing power from the
power company.  These transformers do not pass the HF signals back to
the main power feeders very well, if at all.  Hence, very little
radiation from the main power lines themselves.

In addition, quoting from the article mentioned in another post,

"HomePlug tries to be a good neighbor by avoiding frequencies used by
other power-line technologies. The technology also limits its power
spectral density around the amateur-radio bands by inserting 30-dB
notches in the 4.5- to 21-MHz HomePlug frequency range."

I recently read an article - It was in WIRED magazine, IIRC -which said
that this technology is falling out of favor as the Wi-Fi systems are
becoming cheaper.  And, Wi-Fi is easier to set up, and can be used with
portable computers and devices.  I suspect that is true, I think the
wireless stuff will quickly become cheaper than the plug-in-the-wall
hardware.

Personally, I am much more worried about the UWB (Ultra Wide Bandwidth)
technology that's being pushed right now.  Since that systen is designed
to radiate on the air, I feel it can cause much more damage over a wider
bandwidth than all the HomePlug devices ever will.  Just my $0.02
worth...

73,

Ralph   W5JGV / WC2XSR / 13

http://home.att.net/~shmrg

http://home.att.net/~ralph.hartwell