# The Special Fish Report

## Albert W. Small (December 1944)

### Page 66

Tony Sale's
Codes and Ciphers

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CX/MSS
TOP SECRET Special Fish Report Page 66

P(0 cross in DeltaPSI'A) = A0^2 + 5A1^2 + 10A2^2 + 10A3^2 + 5A4^2 + A5^2
(plus DeltaPSI'B) = .106

1/5 * P(1 cross in DeltaPSI'A) = 2A0A1 + 8A1A2 + 12A2A3 + 8A3A4 + 2A4A5
(plus DeltaPSI'B) = .027

1/10 * P(2 in sum of DeltaPSI's)= .024

1/10 * P(3 in sum of DeltaPSI's)= .026

1/5 * P(4 in sum of DeltaPSI's)= .038

P(5 in sum of DeltaPSI's)= .067

If wrongly overlapped (Delta-D)A + (Delta-D)B can be called

flat in its characteristics (and it is assumed so for the

tables) then:

(Delta-D)A + (Delta-D)B
or (DeltaPSI')A + (DeltaPSI')B Factor in favour of
correct setting
Given: of go-back. D.bans:

0 crosses .106/(1/32) 5.3

1 cross .027/(1/32) -0.7

2 crosses .0241(1/32) -1.2

3 crosses .026/(1/32) -0.7

4 crosses .038/(1/32) 0.8

5 crosses .067/(1/32) 3.4

If a go-back is set properly, it is sometimes desirable to attempt
sum of the
to split the \ Delta psi prime streams back into its original components.

If its original components are more likely to arise from a pair of

crosses than a pair of dots or a dot and a cross, we have gained valuable

knowledge, and can write in some of the motor and thereupon make better guesses.

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