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ARRL General Bulletin ARLB008 (2021)

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ARLB008 Cooperative Effort Under Way to Resolve Potential
70-Centimeter Interference Issue

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ARRL Bulletin 8  ARLB008
From ARRL Headquarters  
Newington CT  March 24, 2021
To all radio amateurs 

SB QST ARL ARLB008
ARLB008 Cooperative Effort Under Way to Resolve Potential
70-Centimeter Interference Issue

ARRL, the FCC, and the US Department of Defense are cooperating in
an effort to eliminate the possibility of amateur radio interference
on 70 centimeters to critical systems at White Sands Missile Range
(WSMR) in New Mexico. The Defense Department's Regional Spectrum
Coordinator contacted the FCC in March, seeking information on whom
to contact regarding detected amateur transmissions it believed
could pose a threat to a critical WSMR system operating on 70
centimeters. The FCC, in turn, asked ARRL to be involved in the
discussion and any necessary remedial efforts. It is to be noted
that the Amateur Radio Service is a secondary service on the band.

Investigation revealed that the potential problem was not with
individual operators or repeaters, but with RF control links at 420
- 430 MHz used to establish a linked repeater system within New
Mexico. "Based on the investigation, and with the support of the
FCC, the owners of the RF control links being used in the 420 - 430
MHz portion of the amateur allocation within a certain proximity to
WSMR are being asked to re-coordinate the link frequency to a new
one above 430 MHz," explained ARRL Regulatory Information Manager
Dan Henderson, N1ND.

ARRL enlisted the assistance of the state's designated repeater
frequency coordinator for information on specific links in that part
of the band. New Mexico Repeater Frequency Coordinator Bill
Kauffman, W5YEJ, agreed to work with the control link operators to
find new frequencies that will meet the needs of the link operators.

"Time is a factor in this request," Henderson said. "The new systems
at WSMR are in advanced testing now and will become fully
operational by early summer 2021." The FCC-imposed deadline for the
affected control links to change frequencies is set for May 31,
2021.

"It appears a total of 32 control links will have to be addressed,"
Henderson said. ARRL has mailed letters to each of the RF control
link operators, based on the recordkeeping of the frequency
coordinator, to advise them of the DoD's request as the primary user
on the band. "Any links with the potential to affect the identified
systems at WSMR still in operation after May 31, 2021 will be
subject to action by the FCC."

Henderson said the changes should have no direct impact on the use
of any local repeater, but until all the affected RF control links
are transitioned to new frequencies, certain links may be
temporarily inoperative. Links unable to be relocated by May 31 will
have to be shut down until the situation can be resolved. ARRL will
be in contact with the FCC after the May 31 deadline to advise it of
the status of the remediation effort.
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