Explanation of the Code
"6EQUJ5"
On the Wow! Computer
Printout
By Jerry Ehman
The photo of the computer printout of the Wow! source shows not only
my handwritten comment ("Wow!") but also the circling of the 6
characters "6EQUJ5" lined up vertically in a column. What is the
meaning of this code?
Each of the first 50 columns of the computer printout shows the
successive values of intensity (or power) received from the Big Ear
radio telescope in each channel (10 kHz wide) in successive 12second
intervals (10 seconds was used for actual sampling and another
approximately 2 seconds was needed for computer processing). In order
to conserve space on the printout, Bob Dixon and I decided to use a
coding method that would result in only one alphanumeric (i.e.,
either alphabetic or numeric) character for each intensity. The
computer was programmed to
keep a continuouslyupdated account for each channel of a baseline
value and an rms value (rms stands for "root mean square", which is
equivalent to the statistical term "standard deviation"). The actual
intensity (after the baseline value was subtracted out) was then
divided by the rms value to obtain a scaled value (i.e., the number
of standard deviations above the baseline). Since there was space for
only one character to be displayed, we decided to take only the
integer value of this scaled intensity for values in the range 0 to
9.999... . The truncated value of zero was printed as a blank
(space). The truncated value of 1, 2, 3, 4, 5, 6, 7, 8, and 9 were
printed directly. For scaled intensities of 10 to 35, inclusive, the
capital letters of the alphabet were used. Thus a truncated value of
10 was printed as an "A", 11 as a "B", etc. If the scaled intensity
ever got to 36.0 or above, the program would simply start over again
at zero (e.g., a truncated value of 38 would be printed the same as
that of 3835=3, namely a "3").
Thus, the "6EQUJ5" code in channel 2 means successive intensities as
follows:
6 > the range 6.0  6.999...
E > the range 14.0  14.999...
Q > the range 26.0  26.999...
U > the range 30.0  30.999...
J > the range 19.0  19.999...
5 > the range 5.0  5.999...
The value "U", meaning the range 30.0  30.999..., was the largest
value ever seen. We do not believe that the intensity ever got above
31.0 and hence no rollover (subtraction of 35) ever occurred. It
would have been easy to spot in a sequence of 6 or 7 numbers that
should follow the antenna pattern of the telescope.
The six successive values in channel 2 fit the antenna pattern of
Big Ear very well.
I have also done a correlation analysis of the six data points with
the mathematical functions: (1) gaussian = normal curve; and
(2)(sin(x)/x)^2. The data fit each of those two functions very well
with correlation coefficients of over 0.99 (i.e., almost a perfect
fit). I also fit the data to each of the two actual antenna patterns
(of the two horns) using the moderately strong radio source OY372.
The correlation coefficients were again over 0.99. There was not
enough difference between the two correlation coefficients to
determine which horn the Wow! source was received in.
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