internet over power line carrier

[2dye4]

Do distribution transformer builder specify their
pole mounted transformers into the 30 Mhz range. I need
these specs to investigate sending data over the power
line for communication in a small physical area.
Thanks

 

[scottf]

I believe for distribution power line carrier, a capacitor is used to couple the communications signal to the power line, i.e. the capacitor is connected in parallel with the distr xfmr.

 

[jbartos]

Suggestion: The frequency of 30MHz is too high.

 

[dpc]

I doubt transformer manuf. have done any testing in the 30 Mhz range.

You might check FCC website and

http://www.arrl.org

for reference links on broadband over power lines (BPL). Most information I have read indicates a lower frequency - maybe 5 to 10 Mhz. But you won't find any data on that either. The BPL advocates have some test installations in the US. I'm hoping it dies a quick death.

 

[tulum]

I believe that PUC Inc of Sault Ste. Marie, Canada was first municipality in Canada to offer residential high-speed Internet service through the power grid.

I don't know much about it, or your application, but maybe you contact someone at PUC??

Here is a news clipping from the Toronto Star (you may have to cut and paste each piece in your browsers address box as one string).

http://www.thestar.ca/NASApp/cs/Con...geid=971358637177&c=Article&cid=1075936210031

Good luck

 

[stevenal]

DPC,

Why the death watch?

 

[killabyte]

check for x-10 transmittion protocol: low data rate over power lines, nice but very narrow bandwidth.

regards

killa

 

[dpc]

stevenal,

The Broadband over Powerlines techology creates serious interference for HF communications, such as amateur radio bands. This should normally mean that the FCC would not allow it. But I guess Michael Powell is too busy watching reruns of the Super Bowl halftime. Federal Emergency Management Agency (FEMA) opposed it, but anything with the word "broadband" in it is golden at the FCC these days.

This technology has already been banned in Japan due to interference concerns.

I believe it is still in the trial stage in the US at this point.

Utilities have enough problems dealing with RFI from noisy insulators, etc without intentionally generating interference.

 

[jghrist]

I would think that the economics in the USA would not be favorable for PLC based internet service. This is because the system would be effectively limited to the secondary of distribution transformers and secondaries in the USA serve few homes. The distribution transformer would be effectively an open circuit at carrier frequencies. Some means of transferring the signal to another communications medium such as fiber would be required at each distribution transformer.

See

http://www.arrl.org/tis/info/HTML/plc/#TUTORIAL

for a discussion of Broadband over Power Line (BPL) and its effect on amateur radio.

 

[2dye4]

jghrist:

That is what I expected. I don't see how broadband
data can survive a distrubution transformer intact.
There is a lot of BS floating around these days in the
press about this.

Thanks
2dye4

 

[jbartos]

Suggestion: The signal would have to be based on a lower frequency carrier that it suitably modulated.

 

[scottf]

As I mentioned above, the technology I have seen uses a coupling capacitor to bypass the distribution transformer....much like power line carrier on transmission lines.

My understanding is that the frequencies will be in the 50-300 kHz range like for transmission lines.

 

[rsherry]

Broadband on power lines is available in certain areas in the UK and europe. It is technically feasible and speed is about 1Mbps symmetrical for customers (obvioulsy the system bandwidth is higher). Try

http://www.hydro.co.uk/broadband

for some info on the pilot schemes in the UK. There are quite a number of equipment manufacturers out there too - providing either an in-house connection (to use the power mains instead of an ethernet cable inside your house) or the external link as provided by the power companies. The substation equipment is expensive and this does impact on its commercial viability compared to standard telecoms links.
Transformers at substations are not a big problem - power companies have been using this idea for many years to carry protection signals on power lines with suitable filters (line traps) as the lines enter the substations. You would want to bypass substations anyway because you dont want your broadband links to die just because you have to open a circuit breaker in a substation.