Hi All, Should this ARRL msg. cause us to worry about the future of mode B operations? 73, Tony, N2UN
[Original Message] From: ARRL Web site [email protected] To: [email protected] Cc: <Subscribed ARRL Members:> Date: 4/24/2007 12:06:01 AM Subject: ARLB013 ARRL aiding effort to mitigate repeater interference to
military radars
SB QST @ ARL $ARLB013 ARLB013 ARRL aiding effort to mitigate repeater interference to military radars
ZCZC AG13 QST de W1AW ARRL Bulletin 13 ARLB013 From ARRL Headquarters Newington CT April 23, 2007 To all radio amateurs
SB QST ARL ARLB013 ARLB013 ARRL aiding effort to mitigate repeater interference to military radars
The ARRL has been working with the US Department of Defense to develop a plan to mitigate alleged interference from 70 cm ham radio repeaters to military radar systems on both coasts. Citing an increasing number of interference complaints, the US Air Force has asked the FCC to order dozens of repeater systems to either mitigate interference to the ''PAVE PAWS'' radars in Massachusetts and California or shut down. Amateur Radio is secondary to government users from 420 to 450 MHz and must not interfere with primary users. The Commission has not yet responded. ARRL Regulatory Information Specialist Dan Henderson, N1ND, stresses that the Defense Department acknowledges Amateur Radio's value in disasters and emergencies and is being extremely cooperative, and a wholesale shutdown of US 70 cm Amateur Radio activity is not in the offing.
''The ARRL Lab is working up calculations on each repeater system the Air Force has identified to determine where interference-mitigation techniques offer a reasonable chance of keeping the repeater on the air,'' Henderson says.
The situation affects 15 repeaters in the vicinity of Otis Air Force Base on Cape Cod, Massachusetts, and more than 100 repeaters within some 140 miles of Beale Air Force Base near Sacramento, California.
A US Air Force contractor identified the problematic repeater systems last summer, but the situation didn't become critical until the Air Force contacted the FCC a month ago. ARRL officials met with Defense Department representatives in late March to discuss alleged interference to the PAVE PAWS radar sites. Henderson has contacted Amateur Radio frequency coordinators in both affected areas.
PAVE PAWS is a missile and satellite detection and tracking system, and its facilities occupy essentially the entire 70 cm band -- one factor that makes mitigation difficult. As a ''first step,'' however, the ARRL is recommending that all affected repeater owners reduce power -- possibly to as little as 5 W effective radiated power (ERP).
''We understand the difficulty this may cause to owners and users,'' Henderson said, ''but the alternative to operating with a smaller coverage area may be not operating at all.''
Henderson says the League is still seeking further information on the problem. ''Until the Defense Department accepts a mitigation plan, repeater owners should exercise patience,'' he cautioned.
Contact Dan Henderson, N1ND, [email protected], or 860-594-0236, with specific questions or issues associated with this situation. NNNN /EX