[aprssig] Future Concept for APRS

[Heikki Hannikainen]

On Mon, 21 Sep 2009, Bob Bruninga  wrote:

> Please, understand that APRS digis RARELY hear every packet, because FM 
> collisions occur MOST OF THE TIME.  Hence, Viscous digipeating is a BAD 
> idea, because it multiples the number of SLOTS taken by each packet, 
> instead of having ALL digipeaters respond at the same time which is the 
> way APRS was designed. Viscous digipeating will really slow down a 
> network and multiply QRM!

It is an EXCELLENT idea for fill-in digipeaters, which only need to 
digipeat if the digipeaters at higher elevations don't catch the packets. 
It does not increase the number of slots taken by a packet in this case, 
when the initial transmission is not heard by the high-elevation digi. Of 
course it must not be enabled on mountaintop sites.

> So APRS in your area is only for vehicle tracking.  That is unfortunate.

I don't agree with everything Matti suggests (like trapping all packets 
for which no position is known), and people do a little messaging, 
some telemetry, weather info, etc, over here. But...

> Vehicle tracking is not of much interest to most hams.  Most hams want 
> to do 2-way communications, not watch some tracker drive around with no 
> way to talk to him...

Like it or not, tracking *is* what most people want to do with APRS.

Thinking from a "product" point of view, it is *the* differentiating 
feature of APRS, when compared to other modes of operation. It's what 
sells APRS. And it *is* the thing that works best in APRS. It doesn't 
suffer that badly from the loss of a few packets here and there. The 
digipeater network was not properly designed for messaging, so it doesn't 
really work too well.

I use APRS mostly in the car. I really don't want to do text messaging in 
the car, it is simply too dangerous. I can do APRS tracking in the car, it 
doesn't distract me at all while driving. I can also do two-way 
communications using the HF/VHF/UHF voice radio, since I can use it while 
keeping my eyes on the road. I suppose that APRS is popular mostly because 
tracking doesn't require *any* effort at all once you have installed the 
tracker, you can (almost) forget about it. And there's no fuss about 
mounting yet another display.

Besides, the most popular and most affordable APRS devices can only do 
tracking. The messaging-capable rigs are still a bit expensive.

Things could be different, if affordable messaging-capable devices were 
there, and if the network would be designed to support it, and the 
digipeaters would be smarter than they are now. I think there's room for a 
lot of design improvements. That is going to require dropping support for 
some of the older hardware and unmaintained software. It's going to 
require some experimentation, and dropping some old fundamental concepts. 
It might be too slow and too hard to do, and another solution (like a 
D-STAR version 2 or 3) might get there first.

   - Hessu