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ARRL General Bulletin ARLB019 (2007)

ARLB019 ARRL Continues Efforts On Interference To PAVE PAWS Radar Sites

QST de W1AW  
ARRL Bulletin 19  ARLB019
From ARRL Headquarters  
Newington CT  August 31, 2007
To all radio amateurs 

ARLB019 ARRL Continues Efforts On Interference To PAVE PAWS Radar Sites

On August 13, the ARRL began sending ''specific mitigation reduction
numbers'' to 122 repeater owners, recommending that they reduce their
signal anywhere from 7 dB to 56 dB, according to ARRL Regulatory
Information Branch Manager Dan Henderson, N1ND. These reductions,
requested by the US Air Force and the Department of Defense, only
concern those repeaters identified by the DoD as affecting the PAVE
PAWS radar system.

''Some reductions are going to be attainable,'' Henderson said. ''You
can do 7 dB, but 56?'' He said such a reduction would ''not be
realistic to achieve. While many of the affected repeater owners may
not be able to achieve the required reductions, but that doesn't
mean they shouldn't try to meet the goal. Everyone involved needs to
continue trying to meet the DoD's requirements. This gives us the
best chance to keep as many of these machines as possible on the

Henderson stressed that any order to shut down a repeater will come
from the Federal Communications Commission, at the request of the
DoD. ''This situation only affects those repeaters on the DoD's list
in Massachusetts and California. It does not affect the everyday,
casual user of 70 cm. This is not a wide-spread threat to the 70 cm

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 or shut down.
The ARRL has been working with the DoD to develop a plan to mitigate
alleged interference from 70 cm ham radio repeaters to this military
radar system on both coasts. According to the DoD, the in-band
interference from Amateur Radio fixed FM voice repeaters has
increased to an unacceptable level. PAVE PAWS radars are used for
national security functions, including early detection of
water-launched missiles. They are critical to our national defense
and are in use 24 hours per day, seven days per week.

The Amateur Radio Service is a secondary user in the 420-450 MHz (70
cm) band, both by the Table of Frequency Allocations and the FCC
Part 97 regulations. As such, Amateur Radio licensees, jointly and
individually, bear the responsibility of mitigating or eliminating
any harmful interference to the primary user, which in this case is
the Government Radiolocation Service that includes the DoD PAVE PAWS


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