[FoxHunt] IARU Transmitter question

[Larry Benko]

I just went back and looked at how I did the IARU patterns.
WPM = 1.2 * #dot periods / second  based on standard word
"PARIS" which is 50 dot periods long including the trailing
7 dot period of silence.

The IARU patterns (including the extra 4 dot times at the end) are:
MOE = 10 + 14 + 4 + 4 = 32 dot periods
MOI = 10 + 14 + 6 + 4 = 34 dot periods
MOS = 10 + 14 + 8 + 4 = 36 dot periods
MOH = 10 + 14 + 8 + 4 = 38 dot periods
MO5 = 10 + 14 + 10 + 4 = 40 dot periods

If sequences all are constrained to be exactly 4.00 seconds long then:
MOE = 1.2 * 32/4 =  9.6 WPM
MOI = 1.2 * 34/4 =  10.2 WPM
MOS = 1.2 * 36/4 =  10.8 WPM
MOH = 1.2 * 38/4 =  11.4 WPM
MO5 = 1.2 * 40/4 =  12.0 WPM

I remember reading somewhere that the desired speed was to be between
8 and 12 WPM.  The above patterns and speeds sound natural since the
proper CW spacing is preserved.  By forcing all sequences into 4.00
second windows the controllers can easily do other patterns than
60 sec. ON and 240 sec. OFF.  We do a lot of hunts at 24 sec. ON and
96 sec. OFF which go faster since there is less dead time.  As an aside
the ID period is also 4.00 sec. which for my call "W0QE" results in it
being sent at 1.2 * 58/4 = 17.4 WPM.  The controller firmware is simple
since all patterns are constrained to be an integer number of sequences
which are always 4.00 seconds.

I have built several controllers for other hunters in the Denver, CO
area and this scheme seems to work pretty well for us.  Also my 80m
foxes are also built on the exact same idea except that the controllers
use the PTT (for oscillator control) and CW output rather the PTT
and audio output that is used on 2m.

73,
Larry Benko, W0QE