Powerline modem

If you have a EE PHD from MIT, go for it. Do you realize that the high fequency transmission characteristics of most peoples "powerline" changes constantly and essentially randomly? - RM

The two remote electric power measurement schemes I know of:

(1) RF transmitter at your meter, "neighborhood" receiver located on a pole, then connection to phone lines.

(2) Modem connection between your meter and *your* phone line. Power company polls your modem.

...Jim Thompson

I guess I was involved in the earliest of powerline carrier communications. Back in 1961 at Femco.

It did not work then and it will not work now.

Ferinstance, an ancient Diablo 630 printer has such a good noise filter that it takes out any X-10 device within 200 feet.

There is work that has used cell phone methods to dynamically adapt the power frequency to fit the power line characteristics. Remember, anytime an expert says something can be done, he/she is probably right; and anytime an expert says something can not be done, he/she is probably wrong. - Rm

Aren't they hard to swallow? ;-)

Hello Rick,

For power metering it seems that the OP only needs a very narrow channel bandwidth. The challenge will be mostly in the analog and filter design arena but it can be done. Then, of course, there are the transformers that need to be bridged.

Regards, Joerg

Hi Don,

Not for broadband. But for low BW communication it can.

Even a brandnew color printer/scanner did that out here. Had to crack out the toroid box and give it an individual choke per wire plus a cap which fixed the problem. Lots of people in our neighborhood keep stashes of Aspirin or Tylenol. I maintain a bucket of $43 toroids.

But remember, X10 is an ancient AM protocol with little noise tolerance. Then I found that almost all modules were off from carrier frequency so after tuning them all up this increased liability greatly. If a suitable multi-frequency narrowband protocol was adopted this kind of appliance control would work like a champ. It's just that nobody seems to do it, they don't see the market potential..

As to power metering I probably would first sit down with the financial people of a cell phone carrier. It doesn't take a lot of their currency (kb/sec) per account to transfer a meter reading.

Regards, Joerg

Hello James,

Don't know. But maybe they'll come out with #43 material with a Cranberry taste...

Regards, Joerg

Powerline communications doesn't work in the 21st century? Really? Gosh somebody forgot to tell these people:

PPL has had running broadband Internet over powerline services in select markets for a few years now. Some other utilties have similar programs.

Utilities not only have another revenue stream and an efficient Internet distribution method, but also gain the benefit of a communications channel to/from their meters.

The ARRL (amateur radio group) has spoken out against some powerline communications, out of fears that it will cause interference to them.

The main bar to this type of information distribution is the need to bridge transformers along the entire data path. This adds cost (and service delaying infrastructure) to what would otherwise be an already 'in place' data path. It certainly has advantages in simplicity over other services.

With very low channel width and appropriate signalling you do not need to bridge transformers. However if complex tariffs are envisaged there may be a need for transmitting up to 24 readings a day per meter and this may be beyond such systems.

Wideband power line systems are effectively wireless systems that use power lines as a rather crude handrail.

I'm sure you can find other methods as well. This part of the industry hasn't yet standardized. Everything still is in 'beta' ;-)

In my neighborhood the "meter reader" plugs a hand-held device into the meter and records the information, my bill is based on three rates: off-peak, on-peak and peak demand.

...Jim Thompson

It's more than fears. There have been several documented instances of interference to radio services. The potenial for interference to the data communications, from radio transmitters also exists.

I did some chip design work for a "modem-per-house" company that was in (IIRC) Toronto. But they lost their funding before they got it working.

BTW, if you haven't heard the news...

"PALO ALTO, Calif., Feb 09, 2005 (United Press International via COMTEX) -- The chairman and chief executive of Hewlett-Packard Co. has resigned suddenly in a dispute with the California company's board."

Good riddance, Carly ;-)

...Jim Thompson

Ding dong, the wicked witch is dead. Now to see if I can't go defibrillate my poor HP shares.

Best regards, Spehro Pefhany

Don't count on it happening really fast:

"The uptick in Hewlett-Packard is purely because of market psychology and will pass as the company still has the same mess in its hand and doesn't have anyone to run the ship long term," said Cummins Catherwood, managing director, Walnut Asset Management.

But given my experience with such experts, maybe the above is a 'buy' signal.

Best regards, Spehro Pefhany