1 Kenwood KT-815 (IF modified) w/6 element yagi indoors - DX Radio

of the National Association of Broadcasters. If you have Adobe Acrobat Reader, you can
read it for yourself on http://www.nab.org/scitech/rbds1998.pdf .
As it turns out, in the United States there is a one-to-one relationship between PI codes
and station call letters. If you receive a PI code, you can calculate which station transmitted
it.
A PI code is a four-digit "hexidecimal" number. In school, you may have learned about
the different number bases. In the base 10 system we normally use in everyday life, the
rightmost digit is the number of units - 10 to the 0th power. The next rightmost is the number
of tens - 10 to the 1st power. Then, the number of hundreds - 10 to the 2nd power. And so
on. In the binary number system, the rightmost digit is the number of units - this time, 2 to the
0th. Then, the number of twos - 2 to the 1st - then the number of fours - 2 to the 2nd - etc.,
etc..
"Hexidecimal" is a fancy word for "base 16". In the "hex" number 7106, 6 is the number
of units. There are no 16s (16^1), 1 256 (16 to the second power), and 7 4096s. (16 to the
third power) Converting to decimal, you get:
4096 * 7 = 28672
256 * 1 = 256
16 * 0 = 0
1 * 6 = 6
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(incidentially, there's an easier way to do this if you have Windows.. Click "Start",
"Programs", "Accessories", "Calculator". Click "View", "Scientific". Click in the circle next to
"Hex", and enter the hex number in the window above "Gradients". Click in the circle next to
"Dec", and the number in the window is automatically converted to decimal.)
Something I've glossed over is what's done with the "extra" digits. In the base 10
number system, there are 10 possible digits: 0123456789. In the base 2 number system,
there are 2 possible digits: 01. In base 16, there are 16 possible digits. We can call the first
ten 0123456789, but what about the other six? We start using the alphabet. So the sixteen
possible digits in the hexidecimal system are 0123456789abcdef. 21C7 is a valid hexidecimal
number. (and it's equal to 8647 in base 10).
The NAB assigned the PI code 1000 hex to the callsign KAAA. KAAB gets 1001,
KAAC gets 1002, etc.. KZZZ works out to 54A7, so WAAA gets 54A8; WAAB 54A9, etc..
There are a couple of exceptions to this orderly arrangement. For technical reasons too
complicated to go into here (but explained in the NAB Web document) codes with 0 in the
second digit like 80A3, and codes with 00 as the last two digits like 5300, don't work reliably.
If the alphabetical system assigns a station 80A3, the zero is removed, the first digit
moved one place to the right, and an A inserted as the first digit. 80A3 becomes A8A3. If the
alphabetical system assigns 5300, *both* zeros are removed. The first two digits are shifted
to the end, and AF inserted as the first two digits. 5300 becomes AF53.
There are a handful of other exceptions. First, three-letter callsigns. These of course
don't map into the four-letter alphabetical system the NAB set up. The codes between 9950
and 9EFF have been reserved for these callsigns, and a specific lookup table has been
established. KGO is 9954, WSM 99A4, etc.. For the most part, only three-letter calls that
actually exist are in the table - though for some reason, the calls KBW, KCY, and KDF
appear. To my knowledge these calls have *never* been assigned to broadcast stations.
They have, however, been used as slogans by low-power TV stations and my bet is that's
what's going on here.
In some circumstances, it's desirable for several transmitters carrying a common
program to use the same PI code. (it is, after all, *Program* Information, not *Station* or
*Transmitter* Information) All codes beginning with B, D, and E have been reserved for
multistation networks.
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