Re: smashing down callsigns into 32 bits
- To: email@example.com
- Subject: Re: smashing down callsigns into 32 bits
- From: firstname.lastname@example.org (Mike Bilow)
- Date: Fri, 02 Dec 94 20:09:00 -0000
- Reply-to: email@example.com
On 94 Dec 02 at 16:49, Fred Goldstein wrote:
FG> The original poster's fallacy, of course, was in forgetting
FG> how to determine permutations. The proper value of a field
FG> AA9AAA is 26^5 * 10, noting of course other formats too so
FG> more likley 27^5 and when you add non-US signs like C21 and
FG> 4N7 it gets a bit bigger... fred k1io
The rule imposed by international treaty is that amateur callsigns are always
exactly 6 characters in the form:
where: X is alphabetic, numeric, or space;
x is alphabetic or numeric;
9 is numeric;
a is alphabetic;
A is alphabetic or space.
There are certain additional restrictions: the 2nd character cannot be numeric
if the 1st character is numeric or a space, and the 1st and 5th characters
cannot both be space. As far as I know, the only callsign that does not
conform to this rule is JY1, used by the king of Jordan.
There are three cases:
1. The 1st character is alphabetic.
26 x 36 x 10 x 26 x 27 x 27 = 177,409,440
2. The 1st character is numeric.
10 x 26 x 10 x 26 x 27 x 27 = 49,280,400
3. The 1st character is space.
1 x 26 x 10 x 26 x 26 x 27 = 4,745,520
Total worldwide callsigns: 231,435,360
Since 24 bits can only represent 16,777,216 permutations, and we need to
represent just under 14 times more values, this is obviously impossible.