As Peter has responded, there are two JA windows; 1810-1825 and
1907.7-1912.5 .
Until a few years ago the JA hams only had the upper 1907.7-1912.5
allocation. Because the band was segmented in much of the world most
international contacts on 160 Meters were done split frequency.
From here in the USA the common method was for US stations to transmit in
the 1.820-1.830 area where their narrow band TX antennas were resonant and
listen for the JA stations in the above 1.9 MHZ JA allocation. The JA
stations would do the opposite, TXing above 1.9 and listening down low.
Initially USA transmitted 1800-1810 on CW, usually below 1805. It wasn't
just JA.
The west coast USA had 1975-2000, the east coast 1800-1825.
ZL only worked up around 1875.
Many Europe and Africa only had 1825 up to 1830, some more.
Now the JA's are still very restricted with the two segments you mentioned
and no SSB. Other places have a variety of areas to operate.
This still does not exclude a DX Window for Europe and the rest of the
world, just because JA can't above 1825.
Also, the OLD standard was USA CQ on the start of the odd fives, and listen
on the even start of 5's when DX CQed. For example, I might CQ at 0500Z and
G3PU at 0505.
http://www.w8ji.com/160%20History/hist160dx.pdf
73 Tom
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Topband reflector - topband@contesting.com
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