[aprssig] Re: javAPRSFilter "AND" logic

[dick at kb7zva.com]

> Similar to the "-" that is used for exclusion filters, a "+" could be used 
> for "AND" logic.

In this case, logic may only be a case of understanding how to implement
a good filter based on its original concept.

Multiple filter definitions can be setup. If any of the filters find a match 
the packet is passed.

There are 12 different kinds of filters that can be used in any combination.
These filters are 'additive' and can be used multiple times. Each filter is 
working independent. This mean if the filter finds a match it will be passed 
to you. 

Example: Up to 9 range filters can be used at the same time to extend the 
areas when you have problem to find a good circle match. We can also
use wildcards (*) on some filters. 

My point is that a "+" really isn't needed, the filters are 'additive' in any
combination. Yes, the minus "-" filtering further allows you to fine tune any
requirements you may have. The type of port you are using also has an
effect on your filtering needs. Some ports in use don't have the ability to
define filtering by default. In that case, it's best to use port 14580 which 
has no filter default. Port 14580 is a clean Igateport on most servers. You 
have to define what exactly what you want to see. Otherwise, you would 
see nothing.

The logic is based on creativity and remembering that the filters are 'additive',
and independent of each other.

You may also try to explain what type of filtering you expect to see and submit
that information to the javAPRSSrvr list on Yahoo Groups, if you are a member.

73,
Dick Stanich, KB7ZVA
APRSWest - Tier 2 Networks