New 20kHz Band Plan (440-450MHz)



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Southern California 440MHz Amateur Community Re-Engineers Entire 440MHz Band Plan

May 10, 1999
-- In accord with well established community band planning procedures, the active southern California A.R.S. 440 MHz community met en masse in Claremont, CA on 1 May and, by consensus, re-engineered the entire 440 - 450 MHz regional "mobile relay" band plan. This is the first major modification to the existing southern California band plan since the normalization of inputs and outputs to 5 MHz spacing in 1977.

The new band plan establishes 50 additional duplex channel pairs in the available repeater spectrum (440 - 450 MHz), an increase from 200 to 250 usable pairs. This provides material spectrum relief for the southern California band which has been effectively "filled" for more than 15 years.

The most important change in the new band plan is the shift from the historically-derived 25 kHz channel spacing to a new narrower 20 kHz channel spacing plan. This plan allows continuing use of the 16K0F3E complaint equipment presently utilized by all existing coordinated and applicant stations. The 20 kHz channel spacing scheme has been in use in southern California for point-to-point links in the 420-440 MHz sub-bands for a number of years, with complete success.

In addition to the new narrower channel spacing plan, the community adopted a channel re-alignment scheme and schedule for present coordinees on the current mobile relay channels, directed the establishment of additional simplex channels, approved the establishment of additional, dedicated "open repeater" and "test-pair" channels, and established a permanent arbitration committee to resolve coordination disputes.

Present at the meeting were representatives from two-thirds (396) of the region’s 611 stations. Representatives from all systems, including those with valid applications on file, were mailed a notice inviting them to attend this meeting. The agreements to make each of the changes to the 440-450 MHz band plan were reached by consensus. In an amazing show of support, the attendees remained present throughout the meeting and participated actively, resulting in completion of business by very early afternoon, an unprecedented occurrence.

This meeting marked the culmination of several years’ preparation and several prior SCRRBA general membership meetings devoted to the subject of improving the utilization and availability of channel pairs in the 440-450 sub band. SCRRBA membership reviewed and directed this preparation through its publicly announced annual meetings. At the 1997 annual SCRRBA general membership meeting, a detailed presentation of the technical parameters required for 12.5 kHz spaced (11K0F3E) operations was made. The membership overwhelmingly rejected such a channel plan. The SCRRBA technical committee was directed by the membership to "go back to the drawing board" to determine, and then present alternatives. At the 1998 annual SCRRBA general membership meeting, several alternatives were discussed, including a 20 kHz spacing plan. A similar detailed technical presentation of the parameters required for 20kHz, 16K0F3E operations was made. The SCRRBA membership directed the SCRRBA staff to schedule a band planning meeting within 6 months to determine the acceptability of such a plan to the entire community of 440-450 relay station operators.

The new band plan will be fully implemented over a twelve month period beginning immediately. The details of the new band plan follow.


Mobile Relay Input Channels 440.000 - 444.980MHz
Mobile Relay Output Channels 445.000 - 449.980MHz


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Present Plan (MHz) New Plan (MHz) Notes
44x.y00 44x.y00 No change
44x.y25 44x.y20 -5kHz change
44x.y50 44x.y40 -10kHz change
none 44x.y60 New channel
44x.y75 44x.y80 +5kHz change

SCRRBA notes that newer synthesized radio equipment is manufactured programmable to 20 kHz channel spacing.  Some older synthesized radio equipment may need modification.  Equipment that uses discrete quartz crystals for frequency control should accommodate the plan utilizing the existing crystals, requiring only "re-netting" of the oscillators.


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The present 44x.y25 and 44x.y75 systems transition will occur first, with completion by August 1, 1999. Some stations will be requested to change to an entirely different frequency pair. This determination will be made by the SCRRBA technical committee. The SCRRBA technical committee will complete notifying most stations of such changes by August 1, 1999. The present 44x.y50 systems transition and first occupancy of the new 44x.y60 channels will occur beginning August 1, 1999. The entire transition of all stations will conclude on or before May 1, 2000. The SCRRBA technical committee will be closely monitoring the presence of stations in the 440-450 band to verify actual channel utilization.


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Two new simplex channels for "ground-based communications" will be established between 446.000 and 446.500 MHz, adding to the existing two simplex channels. SCRRBA will announce the new frequencies as soon as practical after August 1, 1999. A new simplex channel will be established at 449.460 MHz for use by remotely-controlled base stations, which generally operate at high elevations. This channel is not available for use until after August 1, 1999.


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Four new frequency pairs will be devoted to "open repeaters" (i.e., public repeaters), thus bringing the total number of open repeater pairs to twelve. These new open repeater frequency pairs (and potential changes of some existing open repeater pairs) will be announced as soon as practical after August 1, 1999. One additional "test pair" to complement the existing test pair will also be established at 441/446.860 MHz.  This frequency pair is NOT available for use until AFTER August 1, 1999. These "test pairs" are utilized for construction, development, and demonstration of operation of new systems prior to requesting and obtaining coordination of a final operating frequency pair. These test pairs are for ground-based systems only, are uncoordinated, and are shared equally among all systems on those frequency pairs.


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A new arbitration committee was appointed to handle coordination disputes. This committee will initially arbitrate any disputes arising from the transition plan, but will continue past the completion of the plan as a permanent SCRRBA function. The committee consists of ten individuals, each serving for a two year period, staggered annually. Each member is a 440 MHz system coordinee, but is not an officer or member of the technical committee of the SCRRBA organization. The committee will meet at least once each calendar quarter. Arbitration decisions will be binding and not subject to review; disputes remaining after arbitration is complete will be treated as interference problems.  SCRRBA is the recognized southern California frequency coordinator for the A.R.S. 29, 52, 440, 902, 1240 MHz and microwave frequency bands, and is the southern California representative for the above bands to the National Frequency Coordinators Council. For more information about the new band plan, minutes of the band planning meeting, specifics about the Arbitration Committee, and about SCRRBA in general, please see its World Wide Web page


Last modified: April 29, 2009