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OPTIMIZING PROPAGATION ON 630 AND 2200 METERS  THIS STUDY OF OUR NEW MEDIUM
AND LOW FREQUENCY BANDS YIELDED INTERESTING RESULTS.  ROBERT S. LOGAN, NZ5A
PROPAGATION ON OUR NEW FREQUENCY BANDS AT 630 AND 2200 METERS CAN BE QUITE
DIFFERENT FROM WHAT MOST AMATEURS ARE ACCUSTOMED TO EVEN 160 METER
OPERATORS.  TO BETTER UNDERSTAND THE CONDITIONS ON THOSE BANDS, I CONDUCTED
A STUDY OF LOW FREQUENCY STATIONS CALLED NONDIRECTIONAL BEACONS NDBS FOR
THREE WINTER SEASONS FROM 2014 THROUGH 2017.  IN THE UNITED STATES, NDBS
HAVE SERVED AVIATORS AND MARITIME VESSELS AS IMPORTANT AVIGATIONAL AIDS
SINCE 1932, WHEN THE DEPARTMENT OF COMMERCE INSTALLED 83 BEACONS ACROSS THE
COUNTRY.  NDBS TYPICALLY TRANSMIT SLOW SPEED CW MESSAGES AT VARIOUS
FREQUENCIES FROM 190 KHZ TO 535 KHZ, ALTHOUGH THEIR ALLOCATION RANGES UP TO
1750 KHZ.  OTHER COUNTRIES NDB SYSTEMS GENERALLY FOLLOW SIMILAR FREQUENCY
ALLOCATIONS.  FOR EXAMPLE, AUSTRALIAN NDBS TRANSMIT FROM 200 TO 490 KHZ.
NDBS ARE RELEVANT TO THE AMATEUR COMMUNITY FOR THREE REASONS.  FIRST, THEY
PROVIDE REAL TIME PROPAGATION INFORMATION ON FREQUENCIES VERY CLOSE TO THE
NEW BANDS.  FOR EXAMPLE, 630 METERS IS ABOUT 60 KHZ BELOW THE UPPER
FREQUENCY LIMIT FOR DOMESTIC NDBS, WHILE 2200 METERS IS ABOUT 50 KHZ BELOW
THEIR BOTTOM LIMIT.  IN TERMS OF PROPAGATION, THEN, CONDITIONS ON NDB
FREQUENCIES AT ANY GIVEN MOMENT ARE PROBABLY SIMILAR ON THE TWO NEW BANDS,
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