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 Previous: FCC Sets Aside Maine Amateur's License Renewal Grant | ![Next (later) Story](/images/sty-up.gif "Life Aboard ISS "Very Comfortable," Astronaut Tells Japanese Youngsters"){kind=small} Next: Life Aboard ISS "Very Comfortable," Astronaut Tells Japanese Youngsters |
 Mounted on a pole at the left, the Canopy antenna handles the Headquarters building end of the wireless link. The Amateur Radio beam at the right belongs to W1HQ, a station inside the Headquarters building for use by ARRL staff members during their off hours. |
NEWINGTON, CT, Aug 29, 2005--BPL has come to ARRL Headquarters, and preliminary indications are that the newly installed Motorola Powerline LV system will prove Amateur Radio-friendly. Motorola approached ARRL last fall seeking input on a BPL design that could avoid many or most of the interference problems that have plagued some other BPL systems. This past May, Motorola introduced its Powerline LV wireless-to-low voltage BPL solution at the United Telecom Council's "Telecom 2005." The ARRL said at the time that it was "encouraged" by Motorola's approach but reserved judgment until it had the chance to see a system up close. A Motorola Powerline LV system was put into operation at Maxim Memorial Station W1AW this week.
"Theory is great, but the final proof is in how things work out in practice," says ARRL Laboratory Manager Ed Hare, W1RFI, who's been working with Motorola Principal Staff Engineer Dick Illman, AH6EZ. It was an offhand suggestion from Hare that led Motorola to offer to install its system at ARRL to gauge its compatibility with Amateur Radio. Wanting to get as much firsthand information as possible about the performance of the Motorola system, the ARRL readily agreed.
Motorola says its Powerline LV system, which unites its
Canopy wireless broadband Internet platform with enhanced ham band-notching
HomePlug technology, drastically reduces the potential for widespread BPL
interference. Illman says it does this by restricting the application of high-frequency
RF to low-voltage (220 V ac) power lines instead of to medium-voltage wires
that line many residential streets.
 The W1AW end of the Canopy wireless link, which connects to a 220 V ac power drop. The antenna is mounted on W1AW's north tower. |
In addition, Motorola took the HomePlug modem concept to the next step by adding tunable hardware filters to deepen the notches and improve the immunity of the system to nearby ham transmitters.
At ARRL, a Motorola Canopy wireless link has been set up between ARRL Headquarters and W1AW across the parking lot. The system's connected into the League's local area network on the Headquarters side and into a 220 V ac power drop on the W1AW end. Once the system was up and running, Hare and Illman spent several days checking whether the system affected reception on the Amateur Radio bands at W1AW.
"Although more testing needs to be done over the coming weeks, the initial results for Amateur Radio were positive," Hare said. "While it would be hard to envision a BPL system closer to more antennas and receivers, we found only a few dB of BPL noise on one ham band using the highest-gain antenna at W1AW aimed right at the W1AW building."
Hare said that on all other bands and antennas, the BPL noise did not change S-meter readings, nor did it affect readings on the Rohde and Schwarz analyzer and receiver used to make measurements. "This proactive step by Motorola has shown that they are serious about interference issues," said Hare. "More importantly, Motorola has shown that it is possible to achieve enough filtering to protect Amateur Radio under typical conditions."
Hare and Illman also looked into the Powerline LV system's
immunity to the interference from nearby transmitters. As they were testing the
system, Hare recounts, W1AW fired up its bulletin transmissions, putting out with
more than 1000 W simultaneously on seven bands. Hare says that "much to everyone's
delight," data rates via the Powerline LV system connection didn't change after
W1AW began transmitting.
 ARRL Laboratory Manager Ed Hare, W1RFI, examines one of the Motorola Powerline LV modems. The unit plugs into a 120 V ac receptacle, and the user's computer connects via an Ethernet jack. |
"I could hardly imagine a more difficult environment, with part of the BPL-system wiring 30 feet from W1AW's antennas," Hare remarked, "but the system continued as if the station wasn't even on the air." Based on what he's seen so far, Hare believes that most Amateur Radio operation should be possible in proximity to a Motorola Powerline LV installation. The Powerline LV system will remain at ARRL while Hare continues to test the system.
Illman says Motorola is pleased to be working with ARRL on the project, which is being operated under Part 5 Experimental license WC9XGC. "From the beginning of this project, the ARRL staff was upfront with us, and we with them," he said. "We relied on their input and designed a system that we were confident would work exactly as we found here this week."
Illman says that even though the early results were very encouraging, he's learned a lot in the process and has a few ideas on how to make Motorola's product even better.
His trip also marked his first chance to visit ARRL Headquarters in his 37 years as a ham. He said he was thrilled to see the operation, meet the staff and operate from W1AW.
Hare said the League remains committed to protecting
Amateur Radio spectrum and hopes that this early success will encourage other
BPL manufacturers to work with Amateur Radio, not against it. "I want to
extend my thanks to Motorola for working proactively with ARRL," he said. "I
think that together, we have made this first step a good one."
| Previous: FCC Sets Aside Maine Amateur's License Renewal Grant | Next: Life Aboard ISS "Very Comfortable," Astronaut Tells Japanese Youngsters |
