Re: callsign limit

[Ralf Baechle DL5RB <ralf@linux-mips.org>]

On Thu, Jun 01, 2006 at 07:04:02AM -0500, David D. Hagood wrote:

> Ralf Baechle DL5RB wrote:
> >One of my crazier ideas to deal with the issue of the longer callsigns
> >was using a hash value instead.  The probability of colissions is low but
> >how to do the reverse mapping from hash to callsign ...
> 
> Since a callsign is always from the set [A-Z0-9] (36 chars, 5.2 bits of 
> data per character for a naive encoding) could you not simple encode the 
> callsign of an otherwise too-long call as 6 bits per character packed 
> into the octets, with a specific leading character to indicate 
> compression (e.g. '?') - yielding about 8 chars/call.

That is a modest proposal which gives you a little bit of extra headroom.
But the WRC03 rules set no limit for callsigns length.  And, let's face it,
the current format of AX.25 MAC addresses sucks anyway, 7 bytes with
various other junk thrown in just because space was available make
processing more complicated than needed.

73 de DL5RB op Ralf

--
Loc. JN47BS / CQ 14 / ITU 28 / DOK A21