[aprssig] IS-to-RF alternate proposal - 'marked beacons'

Andre aprs at pe1rdw.demon.nl
Fri Dec 30 04:55:21 EST 2011

Op 30-12-2011 10:11, Georg Lukas schreef:
> * Andre<aprs at pe1rdw.demon.nl>  [2011-12-30 03:09]:
>> not a bad idea but you better run a test how large a range you can
>> suport on a 1200 baud channel without making it unusable for local
>> users, I'm afraid that it might be a very small range.
>> I have done a simular test a while ago to see how large a range I
>> could stream on 9k6, about 500 km gave a near 100% load.
> Remember, the goal is to provide _local_ tactical information. The
> filter range should be limited to the expected RF propagation area for
> the chosen path and the local channel conditions.
> What are the chances that your RGATE'd packet actually travels 500km
> over RF?
> Also, RGATE operators have to talk to each other to not create
> overlapping areas, where packets might be duplicated. That means that
> any sane RGATE operator should not set the range to more than half the
> distance to the next RGATE.
> 73 de Georg DO1GL
the 500 km was just the range I used for my aprs stream test on 9k6 and 
qouted as reference point.
my direct range for home stations is about 50 km to 80 km and 2 hops can 
easely get me 150 km out, now if 500 km gives a 100% load on 9k6, 150km 
would probably still be beyond the acceptable load on 2 meter. setting 
the range to half the next RGATE has the problem that they are not going 
to be evenly spread, it could be 10 km to the east and 50 km to the west 
and 30 km north, now what range do you have to set? 5 km would leave a 
huge gap to the west, 25 km would give a huge overlap to the east and 
probably overload the channel.
now if you could pick one single gate there would not be an overlap 
situation but the RGATE proposal does not offer that option.
I'm also wondering how you are going to define local, local on 80 meter 
or Zugspitse  is a lot further then local on 23 cm simplex.
Right now we appear to define local as the aloha circle or in most cases 
2 hops, wich is not a circle either.

it is going to be a lot of compromises.

73 Andre PE1RDW

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