Mon, 25 Mar 2002 14:02:14 -0600
An interesting info article link appeared in the EDN newsletter (trade rag)
this morning. I have seen some previous articles on this technology, but
this one appears to be fairly comprehensive (although it does not address
certain obvious -to me- questions). At this stage, products are not really
into the mass market, but I think this article gives us a fairly good
picture of what we can expect when the consumer versions hit the shelves in
the near future. Note that it does transfer data using at least the 4.5 to
21 MHz frequency range on house power wiring. The article says that a 30dB
notch has been included for the ham bands within that range. After you
read the article, perhaps you would like to contribute to a follow-on of
this preliminary list of non-addressed questions:
1) 30 dB down from what level?
2) What is the full frequency range of the system?
3) What happens with a XX V/m in-band source irradiating the power wires?
(Let's assume a house wired without EMT or metal armor flex.)
4) What happens in condo or apartment buildings when multiple users run
the same system (presumably fed from the same main power transformer)?
Note that the editor who wrote the article has an e-mail address. If you
like, and to avoid bombarding him with a ton of messages, send replies to
me. I'll compile the list and after 3 days, I'll send the unanswered
question list (and other constructive comments that arrive) to him for
consideration. Let's avoid flames and concentrate on straight-forward
technical issues. After all, he might feed some of the comments to the
vendors for consideration. Since they have to get FCC Part 15 approval for
their various systems, any useful comments might help both the
manufacturers and we amateur radio ops. Some of us, of course, might hope
that the whole thing dries up and blows away, but I rather doubt that after
the investments that have been made in developing the chips and technology.
Sound technical input now could help avoid problems later. Incidentally, I
think we should consider it a rare plus that amateur radio even merited a
mention in the article.