[TowerTalk] BPL article.... amazing....!!!

[Jim Lux]

At 04:53 PM 4/26/2004 -0500, wcmoore at verizon.net wrote:
>So if BPL is a Part 15 system then why cannot experimenters use
>BPL type equipment for communications on the power lines
>as long as the experimenter's gear complies with Part 15 requirements? 
>Since they both will be Part 15 device users, can
>either one claim a dominant position?

Part 15 unlicensed doesn't mean total free for all. It's different than low 
powered experimental use. A mfr has to either test or certify that the 
equipment meets the limits in Part 15. Among other things it depends on 
whether it's an unintentional (BPL) or intentional radiator (your ham rig). 
Part 15 isn't hugely complex, but there are a lot of facets, so you kind of 
have to go through it to figure out if your experimental widget falls under 
Part 15, and if so, which flavor of testing, certification, or 
what-have-you is required.  This whole process is called "authorization".

You don't need authorization if you are performing "testing to determine 
compliance", however they're pretty specific that this means lab equipment 
kind of testing, not "customer acceptance" or "market testing"

However, if mfr A has a Part 15 device and mfr B has a Part 15 device, 
neither has priority.

As far as homebuilt devices goes (section 15.23):
(a) Equipment authorization is not required for devices that are not 
marketed, are not constructed from a kit, and are built in quantities of 
five or less for personal use.

That means: no web site advertising the design; no making up kits a'la 
TAPR, etc., etc.

Section (b) goes on to say that testing isn't required, but "good 
engineering practice" is, and you need to follow the operating rules of 
15.5 (accept interference, don't cause interference, etc.)


>The flip side of this is since we are more and more often
>restricted from erecting antennae due to deed restrictions, local 
>ordinances and grousing neighbors, can we use the AC Power
>system as a transmission line and antenna? 100 watts on the
>AC line? Maybe 1500 watts? I know the XYL would be thrilled to see me take 
>down the dipoles and simply plug into the wall socket.
>It would be a more esthetically acceptable solution in the view of many.


A fascinating idea...  I can see putting an RF choke on the incoming power 
line at your panel and putting an RF coupler to the "line" side of the choke.

You're not in Part 15 territory here, but Part 97, since you're licensed, 
and an intentional radiator to boot.  I suspect that, if read carefully, 
your power company probably has rules in their tariff that prohibit you 
from doing this (either in some form of prohibition against excessive 
inteference from your loads, or against reverse power (really intended to 
be line frequency, as in backfeeding a generator, but probably broadly 
written).

They also currently use PLC (power line carrier) techniques to turn user 
loads on and off, and your HF signals might interfere.

Casually looking through Southern California Edison's Tariff.... 
http://www.sce.com/NR/sc3/tm2/pdf/Rule2.pdf (page 9) Rule 2, E. 
Interference with Service:

"3. Any customer who superimposes a current of any frequency upon any part 
of his electrical system, other than the current supplied by SCE, shall, at 
his expense, prevent the transmission of such current beyond his electrical 
system."

Even more gory details at:
http://www.sce.com/NR/rdonlyres/eksfg5hozof4g7dqwcxejdl4angzvc2ebgyrugxwhfccumvzgrcgqfxgtozacp6pmi4pfqpg2dtt35ipjx6hftqev2h/esr_March_05_2004.pdf



>Chuck WD4HXG
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