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This topic comprises 2 pages: 1 2
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Author
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Topic: Broadband Over Power Lines
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Rick Raskin
Phenomenal Film Handler
Posts: 1100
From: Manassas Virginia
Registered: Jan 2003
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posted 10-22-2004 07:17 AM
This was in our home town paper this morning:
Hams display interference from BPL
By SARI KRIEGER
skrieger@manassasjm.com
Friday, October 22, 2004
When Federal Communications Commission officials came to Manassas last week, they saw a resident make a phone call using the city's Broadband over Power Line technology.
The Oaks of Wellington retirement community resident relied solely on that telephone for his land-line use and needing no telephone line. But in an emergency, some say that resident may not be able to make a call.
Manassas became the first American locality to implement BPL citywide last year. By plugging a modem into any city electrical outlet, subscribers can gain high-speed Internet access starting at $27 per month, approximately half of what cable and DSL providers charge.
Many short wave radio users, including amateur radio users, or "hams," have opposed this technology for its interference. BPL radiates off the power lines and can make certain short wave radio frequencies inaudible. Radio frequencies can be compared to television channels.
Hams use amateur radios to communicate with other users around the world. Other short wave radio uses include citizen's band radios, foreign broadcasts and emergency communications radios used by some government agencies.
The frequencies used by hams in Manassas have been "notched," or removed from use by BPL, in some neighborhoods.
The FCC adopted rules for BPL last week, including some provisions to deal with interference.
Hams and others still worry, not only for their technology, but for people relying on BPL.
The Ole Virginia Hams, a local amateur radio club, has been watching the issue in Manassas. Member Bob Zaepfel signed up for BPL and acts as a liaison for the club concerning BPL issues. The city notched outside his Longstreet Drive house, so he can use his ham radio without interference or static.
Zaepfel demonstrated Wednesday how quickly BPL allows him to download a large file. But when OVH members Don "Butch" Blasdell or George Tarnovsky used their ham radios in a truck outside Zaepfel's house, the file stopped downloading. It resumed when the ham stopped transmitting.
Manassas Utilities Department Director Allen Todd, also a ham radio user, hadn't heard of any complaints in Manassas or nationally about this, he said.
"Once we see what the problem may be, I'm sure we can take some kind of action to prevent that from reoccurring," Todd said.
An amateur radio user would not realize he or she is stopping a neighbor's BPL use, the OVH members said.
"I could knock out this entire neighborhood," Zaepfel said. "It's one of the aspects of this situation they don't want to talk about."
By adding equipment to the current power grid, the city has outfitted approximately 3,000 to 4,000 city houses with BPL technology. Approximately 900 people have signed up for the service.
The hams worry more about what will happen when the entire city and other jurisdictions begin using BPL.
Although the city notched the ham frequencies, it didn't notch other short wave frequencies. A radio station from Canada was barely audible on the radio in Tarnovsky's truck.
The city can continue to notch out frequencies, but as more and more people subscribe to BPL, not enough frequencies will remain, the hams said.
Zaepfel compared it to narrowing a water pipe, which makes the water flow through slower.
"If you notch out enough of your frequencies, you won't have enough bandwidth for your users," Zaepfel said. "It will be slow as molasses."
But the city can notch for individual homes and not decrease bandwidth for other city areas, Todd said.
"You don't do the whole city," Todd said. "If one customer had an issue because that's the station they like to listen to, we can go out and notch their house and not affect other people. And we can do that from the office."
Driving in his truck on Shannon Lane in Manassas, where ham frequencies haven't been notched, Tarnovsky explained the static heard on his radio. BPL caused this static, which was 11 times more noisy than normal, he said.
The radio sounded mostly static-free after driving away.
While some static can be blamed on the atmosphere and sun spots, that pales in comparison to BPL noise, Tarnovsky said.
Tarnovsky posted a recording of the noise on his Web site at
http://www.target-eng.com/ bpl/bpl.htm.
But what if utilities or companies implementing BPL in other areas aren't as accommodating as the Manassas Utilities Department, hams wonder.
Amateur radios are a licensed use with the FCC, and therefore can not be interfered with in general. The FCC's recent ruling on BPL required the Internet technology to stay away from frequencies used by government for public safety, but the language about ham radio and other uses was not as stringent.
The Manassas BPL system can monitor power outages, allow security cameras on lamp posts and help with city traffic lights.
If the transmission outside Zaepfel's house stops his download, the hams wonder if a ham using a mobile radio in his vehicle could be able to stop city traffic lights too?
In response to a question about BPL's potential to interfere with United States Coast Guard communications, Zaepfel said a former OVH member arranged for a United States Navy official to visit Manassas next week to check on the BPL system's interference.
He declined to name the official or give his contact information for comment.
Most hams have "signed off" on the Manassas project, Power line industry representative Alan Shark wrote to this newspaper:
"While they might like to think we've been placated, they're still interfering," Zaepfel said.
Zaepfel believes a solution can be reached, and prefers not to just argue.
But the hams plan to continue monitoring the situation and file a complaint with the FCC and the city if necessary.
Manassas could have simply chosen a different BPL system, using higher frequencies, which may even work better, Tarnovsky said.
"If [BPL] was a viable service, it would be awesome," Tarnovsky said. "But down at the low bands, that's just a poor choice, especially when other means are available."
When Manassas chose the current system, it looked for an FCC compliant, deployable system, Todd said. This system works, he said.
"Whatever issues that may develop concerning short wave, amateur radios or any other situation may come, we will comply with the [FCC] order," Todd said. "And we think our system will do that."
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