and we can see therefore that while D text was random in appearance,
Delta-D text will not be random, being the sum of Delta-PSI'(with definite
characteristics)
and Delta-P (with definite characteristics).
Characteristics of Delta-D
Thus a set of Delta-D characteristics for late April and early May
Jellyfish Berlin (20 motor dots) is as follows, based on 16 messages"normalised"
to 3,200 letters length:
/ ..... 128 R .x.x. 92 A xx... 96 D x..x. 89
9 ..x.. 110 C .xxx. 90 U xxx.. 124 F x.xx. 100
H ..x.x 102 V .xxxx 94 Q xxx.x 101 X x.xxx 87
T ....x 99 G .x.xx 100 W xx..X 89 B x..xx 82
O ...xx 104 L .x..x 92 5 xx.xx 143 Z x...x 89
M ..xxx 100 P .xx.x 96 8 xxxxx 112 Y x.x.x 97
N ..xx. 100 I .xx.. 96 K xxxx. 89 S x.x.. 104
3 ...x. 113 4 .x... 90 J xx.x. 103 E x.... 89
Total 3,200
I might add that the Delta-D characteristic frequencies are so important to the
successful prosecution of the Fish problem, that practically every man,
every Wren, in the Newmanry and in the Testery, knows them by heart, together
with the variations to be expected on the different circuits and among the
different correspondents. The solution of equation (1) is not considered
complete unless the results match the expected Delta-D characteristics; and
Maj. Tester's section utilises these to the fullest in the art of converting
Delta-D into plain text.
From the above table of deltaD characteristics, the following
important facts about the various impulses of Delta-D result: