For many years, the ARRL International DX Competition rules specified that
the exchange for DX stations was a 5-digit number (6 on CW) consisting of a
signal report and "approximate 3-digit transmitter input power in watts".
It was not clear what a DX station running 1000 watts should send, since
that is 4 digits. I seem to recall some stations sending "999" as their
In the announcement for the 1979 DX Competition (January 1979 QST, page
86), the definition of the exchange for DX stations had this sentence added:
"An input of 1000 watts would be indicated by 000."
This may have been the only year this note was added but it made an
impression on many of us at the time and the tradition of "000" = 1000
Watts stood for a long time. And for the speed demons insisting on using
cut numbers, "TTT" equaled "000" equaled 1000 watts.
The 1980 DX Contest rules did not mention the "000" exchange. It was also
the year that the official name of the event was changed from "Competition"
to "Contest" and was the ill-fated one-year experiment that allowed
I'm not sure "000" was ever mentioned in print again, other than in an
article by W6ISQ (I think) about a DX contest experience where he asked a
station "How can you be running zero watts?". Maybe someone can find that
The current rules allow DX stations to send "number or abbreviation
indicating approximate transmitter output power".
(who happily had a computer send "5NNK" a few thousand times last weekend)
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