This is a follow up from Ed, I believe that he provides an excellent explanation as to why ARRL is encouraged by Motorola’s technology.

 

Please route questions through me – I won’t filter them, I’ll just collect them together so as to minimize impact to Ed’s schedule.

 

He’s a very busy man!

 

Ed, your work and time spent in all that you do is greatly appreciated!

 

Todd Cady – K7PKT

 

 

-----Original Message-----
From: Hare, Ed W1RFI [mailto:[email protected]]
Sent: Tuesday, May 31, 2005 2:51 PM
To: Todd Cady
Subject: RE: Hams Encouraged by NEW Motorola BPL Technology

 

Hi, Todd,

Did you see this post from [email protected]?  You may share this with others.

Ed Hare, W1RFI
ARRL Laboratory Manager
225 Main St
Newington, CT 06013
Tel: 860-594-0318
Internet: [email protected]
Web: http://www.arrl.org/tis
Member: ASC C63 EMC Committee
   Chairman: Subcommittee 5, Immunity
   Chairman: Ad hoc BPL Working Group
Member: IEEE, Standards Association, Electromagnetic Compatibility Society
Member: IEEE SCC-28 RF Safety
Member: IEEE EMC Society Standards Development Committee
   Chairman, BPL Study Project
Member: Society of Automotive Engineers EMC/EMR Committee
Board of Directors: QRP Amateur Radio Club International

Here's a draft of my personal viewpoint on all this:
As BPL systems have deployed, ARRL has been concerned about  interference they can cause.  To protect amateur radio and  other sensitive radio communications, BPL systems must operate with emissions below the level of the signals that are being received from licensed radio transmitters. To date, BPL systems have not done this very well, and interference has been the result in most of the BPL deployments.

In November of 2004, Motorola contacted ARRL, asking for information about what what was needed to have a BPL-system design that could operate compatibly with licensed amateur users.  Motorola and ARRL staff exchanged information and ideas about how this could be done.  Motorola's new BPL design -- the Motorola Powerline LV solution -- included ARRL's input in a design that is intended to be used in a way that has the potential to address interference to amateur radio.

The PowerLine LV solution is designed differently than other BPL systems. It does not operate BPL at all on the medium-voltage (MV) distribution lines. Motorola recognized that avoiding the MV lines is essential to avoid strong radio emissions over a large geographical area. The backbone of the system is wireless, using Motorola Canopy equipment. 

The system then uses HomePlug V1.01 signals over the 240/120-volt low-voltage (LV) lines to get from the wireless backbone into homes and businesses.   LV wiring generally has a much smaller interference footprint area than overhead lines. In addition, the HomePlug specification doesn't use carriers in most of the amateur bands, and HomePlug modems generate signals only when in actual use.  While this offers some protection to amateur radio, Motorola has taken one more important step further and has added additional passive filtering to reduce emissions in the amateur bands by a significant amount. ARRL believes that this combination should be effective at preventing interference to amateur radio.  The system also can inherently implement an "all-wireless" solution to take care of any remaining problems if needed.

The proof of this concept will be final only when these systems are tested in the field.  Motorola is working with ARRL and local amateurs in its initial deployment areas, to show whether what looks good in the laboratory will work as designed when used in various installations.   The design approach of the Motorola Powerline LV solution appears to meet the goals that ARRL has described for emissions levels and protection of amateur communications. 

ARRL appreciates the cooperative and proactive approach of Motorola and the detailed exchange of information. We are enthusiastic about the potential of this approach.  We are looking forward to testing this in the field and continuing to work with this industry to help design products that are compatible with amateur radio and other radicommunications systems. 

Ed Hare, ARRL Laboratory Manager