[MNAPRS] Does the metro have too many WIDE digis

[Doug Reed]

Hi All.

Have any of you been listening to 144.390 and watching the packet 
decodes on your home station? In St Paul/Mpls it looks about as bad as 
before the New-N paradigm went into effect. I'm seeing 4 to 6 repeats of 
MANY packet beacons. And I'm seeing a lot more stations responding as 
WIDE digis.

Three mitigating factors....
1. My home station is pretty good. I hear main digis for 100 miles 
pretty regular. Today I was hearing AITKIN and Austin direct too.
2. Propagation conditions are better than average today.
3. Some WIDEs are not optimum from the software standpoint.

The following are my opinions, whether we choose to follow them is up to 
the group.

Main WIDE digis:
Should be high locations, typically 100' or higher, 200' or higher 
preferred. Want to be heard by home stations 60-80 miles away, minimum.
Should NOT respond to WIDE1-1 unless it is the only WIDE in the area. 
This is NOT the case in the metro area.
Should try to limit most paths to WIDE2 or less, truncate anything over 
WIDE3.
Should respond to MNn-n paths for emergency or special purpose.
If Kantronics, should be using v9.1 or later software to eliminate WIDE1 
errors. Kantronics v8.1 or v8.2 isn't good enough. :-(
Should generate real Bell 201/packet/APRS tones, not TinyTracker 
waveform. (Listen to it on an HT and wonder why it works at all.)
MUST be setup for NO TX hold-off. MUST practice fratricide (be IMPOLITE) 
to meet the New-N paradigm requirements.
Can all WIDE digis be setup to use TXDELAY of 200ms or maybe 150ms? Less 
TDELAY means less wasted time on repeats.
UIDIGI v1.9 is OK for a WIDE digi but not as good as Kantronics v9.1.
(I'm not familiar with DigiNED or other software. And I wouldn't use a 
PC-based computer at a remote WIDE site if I can help it.)


Home (Fill) digis:
This category includes any fixed digi that is NOT required as a main 
digi for the area. Typically installed 25'-120' above ground, 25W max?
Must ONLY respond to WIDE1-1 and will be POLITE about it, waiting for 
the channel to clear after it hears a beacon. This allows any main WIDE 
to TX first.
Prefer that if it hears the packet digi'ed by someone else, it should 
abort its transmission. i.e. if anyone else TXed the packet, I don't 
have to. This advanced feature may not be available in all software.
Should NEVER TX its OWN beacons with WIDE1-1 in the path.
Should ALWAYS do callsign substitution when digipeating packets so it 
does NOT require 10 minute ID beacons.
Does not move very fast so should TX its beacon LESS than 4 per hour.
Kantronics v8.1 or v8.2 software will work for fill digis.
CW ID should always be turned OFF. I haven't heard this error in a while.


Mobile trackers:
If it moves, this is the correct category.
Assumes 0'-25' antenna mounting height and under 50W of power.
If a high-power TX, use beacon path WIDE2-2 for the path. If low power 
TX, use beacon path WIDE1-1,WIDE2-1 in the metro area and most of MN. 
This will get you to an Igate from anywhere in the state, if you are 
heard at all. You will also be heard via RF by anyone in your area.
Normally will NOT respond to WIDE1-1 beacons unless it is a 
better-than-average mobile or emergency or special purpose station.
May use MNn-n path if required for the tracker's purpose.
May digi packets heard using MNn-n path if required for it's purpose.


Portable trackers:
Should never be configured as a DIGI since it will always be limited by 
antenna, radio or available power supply.
Should use WIDE1-1,WIDE2-1 or WIDE1-1,WIDE2-2 as beacon path.
May use MNn-n path if required for the tracker's purpose.

-----------------------

Does this fit with everyone's understanding of the New-N paradigm for 
APRS? Have I missed any new updates to the setup?

My reasoning is twofold:
1. Get all beacon transmissions to an Igate somewhere in the area.
2. Direct RF paths is not important more than 50-100 miles away.

If the beacon gets to an Igate, anyone can locate the station using one 
of the APRS web sites and do it from anywhere in the world, without 
requiring a license or a radio.

The direct RF path between stations is seldom important unless they wish 
to talk via RF, and that will be limited by local repeaters or simplex 
coverage.

In the case of using APRS during an ARRL VHF-UHF contest, the rules 
prohibit using "existing infrastructure" so it will need to be done on 
some simplex frequency and all participating stations should be 
configured as mobile digis.

------------------------

We have a number of very good WIDEs in the metro area and therefore 
don't require a lot of home stations operating beyond WIDE1-1. If all 
those main WIDE digis were configured correctly and using new enough 
software, that would cut down the extra repeats quite a bit.

If the home and fill digis would drop packets that were already 
repeated, that would help more. If they would ignore WIDE2 and above it 
would help even more.

I admit to needing to replace a couple Kantronics v8.x digis with 
Kantronics v9.1 or UIDIGI v1.9, or demote the v8.2 TNCs to fill digis. I 
haven't done a detailed check of the local APRS traffic to see who else 
might need to change their setup.... Who knows, maybe it isn't as bad as 
it looks......

73, Doug Reed, N0NAS.