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[aprssig] Weather Stations and Net Neutrality

Steve Dimse steve at dimse.com
Fri Aug 15 21:30:48 UTC 2008


On Aug 15, 2008, at 3:48 PM, Robert Bruninga wrote:

> Because Weather without position is meaningless.  Whereas
> Messages and most Status's  usually have meaning that is mostly
> independent of position.

I disagree totally. Very few messages and status messages stand on  
their own. The whole point of using APRS o text someone is you know  
where they are. I made this a key feature of reverse IGating - sending  
messages from the internet to RF ten years ago. Igates keep exactly  
the buffer I have talked about, the last position for all stations it  
hears. When a station on the internet sends a message to someone on an  
RF network, the IGate takes that last position and sends it on RF.  
That way, an RF station can see the psotion of who they are taling to.  
Magic.

You could have put position in each message, but you didn't. No big  
deal, easy to work around. But weather is just too hard?
>
>> and  positionless telemetry, which requires up
>> to FOUR separate packets (position, parameters,
>> bits and data) to be fully useful, and is also
>> your creation.
>
> Yes, I agree telemetry is an exception that does require
> additional apriori information for full meaning.

No, it didn't _need_ to be an exception. Even if you want to exclude  
params and bits from the discussion, you could have written a  
telemetry format which included position, but you didn't! Still,  
somehow, you manage to make telemetry work just fine in your software,  
associating a position received before or after the telemetry data.  
Amazing! But you cannot do it with weather?

> But it is
> several orders of magnitude less significant on APRS than
> weather which everyone uses, not 0.1% that use telemetry.

And therefore much more important that bandwidth be saved by  
unnecessary positions!
>
> When I am driving down the road, and have a black cloud ahead, I
> want to look at my APRS radio for the nearest WX station ahead
> of me and see what is going on.

First of all, this would be (barely) useful if there were APRS weather  
stations with the density to be likely to provide helpful info. The  
odds of finding an APRS weather station under a random dark cloud are  
pretty slim.

If I'm driving and see a dark cloud, I pick up my iPhone, and press  
the icon on the front page which pulls up this URL:

http://www.findu.com/cgi-bin/radar-find.cgi?call=k4hg-8&zoom=50&offsetx=500&offsety=500

In 10 seconds I'm looking at a beautiful radar image centered on my  
truck's last reported position. The size of this image is optimized  
for the iphone, display starts zoomed all the way out (about 35 mile  
radius), and you can pinch zoom in if you want more detail. Any  
weather warnings are drawn by the NWS on this map, if I see something  
I want to read I use another bookmark on the iPhone desktop to warn- 
near.cgi, showing a sorted list of warnings by distance from the  
center of warning to my car. The text of any warning can be pulled up  
with a tap.

I've used two different systems to do what they do best. APRS is great  
for getting short data, like my position, from a mobile to the  
internet on an ongoing basis. (If Apple ever approves my findU app,  
even that can be done on the iPhone.) I've used the mobile internet to  
download a 10k image that would tie up 144.39 a couple minutes to  
transfer if you tried.

And, if I really wanted to use APRS weather stations, I can use wx- 
near.cgi on the iPhone to see those stations near me. Or, I could  
add ,* to the callsign in the above URL, this adds all the APRS  
stations on the radar image

This was exactly what I imagined when I began findU. Combining the  
data from APRS with the other data sources out there. I had hoped  
amateur radio would supply the downstream mobile bandwidth I needed. I  
donated a lot of money to TAPR's spread spectrum data radio project.  
That project failed. There is no other in the wings.

Face reality. There will never be enough amateur digital bandwidth  
built out to match the useful bandwidth to mobiles that mobile  
internet has today. It was a nice dream, but it is over. Ham radio  
could not match the economy of scale of the cell phone industry. I  
say, use each system for what it does best.

Do it the way you want, but I'll be a lot drier than you!

> In the mobile environment with
> positionless weather being reported, it might be one to two
> hours before my radio can integrate the positionless-weather
> being reported every 10 minutes to the weatherless-position
> report that only comes out once an hour.  In the meantime, I am
> wet and mad at having an APRS system that is delivering useless
> weather packets that I have no idea where they are coming from.

This would be a one in a million shot, a weather station under the  
cloud that provides enough information to prevent you from getting  
wet, and where you happen to miss the last few positions. Of course, a  
station without rain would be a very important piece of info as well,  
but you hope not to see them because their transmit rate has decayed!

And as always, if you really need to know a station's position, you  
can send ?APRSP? to them.

Steve K4HG






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