Re: Order to vacate 420 to 430 MHz

Brian Mileshosky

Jim and everyone —

Please disregard (most) of the original note below.  While WSMR is indeed bringing about a capability that is sensitive around that part of the 70cm band, the FCC has *not* issued an order, in any shape or form, for anybody anywhere to vacate that part of the band by anytime. 

ARRL is working in real-time with FCC, WSMR and DOD’s spectral management office to understand the issue and jointly explore avenues to mitigate interference with minimal impact to the amateur radio community.  They are working to limit potential impacts only a few links on specific frequencies in specific areas adjacent to WSMR...not all occupants of an entire sub-band across a broad geographic area.

For now, it’s best to treat this as “for awareness only” and await official guidance from ARRL based on what they, WSMR, DOD, and FCC determine is and message the least impactful path forward.

The original messaging below has certain inaccuracies that shouldn’t be propagated further to prevent any sort of panic. Bill W5YEJ has since issued a correction stating that no such FCC order exists. 

Brian N5ZGT 

On Mar 19, 2021, at 13:29, KC7QY <kc7qy@...> wrote:

FYI - From a message sent out by Bill W5YEJ on the repeater owners group.

"Per request of the U.S. Army the FCC had ordered that we vacate the 420 to
430 MHz segment of the 70cm band to make way for a new project on WSMR.
Area included: All Amateur transmitters within LOS of WSMR and any other
location that may cause interference on the Range. Sandia Peak, Manzano
Mtns, Capilla, Organ Pass, Benson Ridge, Long Ridge, Buck Mountain & El
Paso are all within the area of concern as well as the Tularosa Basin.
This list is not all inclusive and may need to be expanded if interference
is found at sources outside the LOS area.
Note that frequency coordination is primarily used to protect receivers
from unwanted signals. In this case the receiver(s) location is not
specified and so is a bit difficult to determine which, if any, other
locations may need to be included.
When: FCC has said we must vacate the band segment or turn off any
transmitters within the 420-430 range by May 31, 2021. This doesn't give
us a lot of time to rearrange channels.
What do you need to do? If you're operating transmitters (links or
repeaters) with the range of 420 to 430 please contact me ASAP so I can
verify the NMFCC database is up to date. I was officially notified of this
order on March 16th and have been trying to come up with a plan to move
transmitters. If you have suggestions please let me know. FYI, here is
the band plan from the ARRL:
70 Centimeters (420-450 MHz)
420.00-426.00 ATV repeater or simplex with 421.25 MHz video carrier
control links and experimental
426.00-432.00 ATV simplex with 427.250-MHz video carrier frequency
432.00-432.07 EME (Earth-Moon-Earth)
432.07-432.10 Weak-signal CW
432.10 70-cm calling frequency
432.10-432.30 Mixed-mode and weak-signal work
432.30-432.40 Propagation beacons
432.40-433.00 Mixed-mode and weak-signal work
433.00-435.00 Auxiliary/repeater links
435.00-438.00 Satellite only (internationally)
438.00-444.00 ATV repeater input with 439.250-MHz video carrier frequency
and repeater links
442.00-445.00 Repeater inputs and outputs (local option)
445.00-447.00 Shared by auxiliary and control links, repeaters and
simplex (local option)
446.00 National simplex frequency
447.00-450.00 Repeater inputs and outputs (local option)
I suggest we use the 433.00-435.00 and 438.00-440.00 segments to move
transmitters currently in the 420-430 segment. Paul Choc advises some of
his equipment may not go high enough to operate in the 438 MHz range and
has suggested we might use 430.00-430.975 MHz and 434.00-434.975 MHz (4 MHz
split) for some links. I am soliciting your comments on both of these
suggestions whether or not you are affected. I don't want to make
unilateral changes that will impact Amateur operation on the 70cm band for
so long as we are operating there (and I wont be around that long anyway).
I would prefer your comments in writing so I have a record but you are also
welcome to call me any time.
Bill, W5YEJ"


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