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ZL3AI > APRDIG 23.04.03 09:24l 301 Lines 13738 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: WXTrak is now available
From: "Russ Chadwick" <russ@wxqa.com>
Date: Sun, 20 Apr 2003 21:04:58 -0000
X-Message-Number: 25
----- Original Message -----
From: "Gerry Creager N5JXS" <gerry.creager@tamu.edu>
To: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Cc: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Sent: Sunday, April 20, 2003 7:56 PM
Subject: [aprssig] Re: WXTrak is now available
>Mesoscale use of weather data can make use of it at a finer granularity
>than 15 minutes. And I might note that, because of the processing
>involved, the APRSWXNET data can be delayed almost an hour in reporting.
>It's still more timely than some of the other sites available today.
APRSWXNET data is time-stamped when they are received at findu.com (in order
to avoid relying on individual station clocks). This assumes that APRS-IS
only has small delays. So, when the data get to NOAA. they have times
associated with each data point so that they are put into the proper bins
(or tanks as they are sometimes called) for numerical weather prediction.
Here's a way to check the internet delay from Antwerp, Belgium, at least.
Marc, CW0009, sends data to APRS-IS every quarter hour. His station sends
the data packet within 1 second after the quarter hour. You can check when
each packet was received at findu.com by going to this page
http://www.findu.com/cgi-bin/wx.cgi?call=CW0009
and looking at how much each measurement is timed after the quarter hour.
The delays are usually between 10 and 20 seconds, which is not a problem for
this weather data.
Russ Chadwick KB0TVJ
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Subject: Re: WXTrak is now available
From: James Jefferson <jjeffers@aprsworld.net>
Date: Sun, 20 Apr 2003 16:26:05 -0500
X-Message-Number: 26
>and looking at how much each measurement is timed after the quarter hour.
>The delays are usually between 10 and 20 seconds, which is not a problem
>for this weather data.
Russ and List, I did some experiments using aprsworld.net data for this.
I wrote software to compare the time contained in a trackers NMEA packet (with
valid GPS lock and presumably valid time) as compared to db.aprsworld.net's
NTP set local clock.
If memory serves me, this time two years ago the network propogation delay
from a station transmitting before it entered into aprsworld.net was around
3.
Here are the results from today:
Based on 8508 samples (where difference < 60, to get rid of unlocked):
Minimum propogation time: 0
Maximum propogation time: 59
Average propogation time: 7.17054536906
-Jim
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Subject: Re: NMEA sentences from TM-D700A
From: WA8LMF2@aol.com
Date: Sun, 20 Apr 2003 17:34:42 EDT
X-Message-Number: 27
In a message dated 4/20/2003 1:13:29 PM Pacific Daylight Time,
ik7565@erols.com writes:
>Or can I get it from the DIN port?
The DIN port is just TX and TX AUDIO, PTT and RX squelch line. This
connector is standardized across all the Japanese ham mfrs now -- it's a
perfect place to connect a sound card interface or a hardware TNC.
> Or do I have to split the signal
> coming down the GPS cable? Thanks!
This is likely to be the most successful. The Kenwood WILL echo GPS data
out the DB9 port when it is in the "PACKET" mode but not during the
standalone "APRS" mode.
Stephen H. Smith wa8lmf @ aol.com
Home Page: http://wa8lmf.com
Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
APRS Stuff
http://members.aol.com/wa8lmf/aprs
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Subject: WX: was something about TinyWX
From: "Spider" <spider@rivcom.net>
Date: Sun, 20 Apr 2003 14:42:35 -0700
X-Message-Number: 28
(bounced three times on tapr sig....rewrite below)
>>Mesoscale use of weather data can make use of it at a finer granularity
>>than 15 minutes. And I might note that, because of the processing
>>involved, the APRSWXNET data can be delayed almost an hour in reporting.
>> It's still more timely than some of the other sites available today.
>>
>>gerry
It's delayed coming from ????
Some of the stuff Utah is using is quite interesting. I can not, for the
life of me, remember the name of their new system...Rambo, or something
like that.....but I've asked that they include APRSWXNET data on it....and
I hope Russ pursues this issue someday. I know permissions of theAPRSWX
stations are needed, they certainly can have mine and I can not see why
anyone would object to the Utah Meso guys having this data. It's public
data anyway!
You are right, Gerry! There are delays For example, Utah is using or
including AZMET as "real-time" data! AZmet is read once at midnight! If
someone where to quickly need data and not know that....they just might be
surprised on what really is. AZMET is VERY slooooow.....they "could" be
really fast if they would pull their heads out of the sand and use
APRS...and they would even reduce cost! This is a perfect example of a
different standard. They are not doing what they do for "real-time
purposes...but more for research and study applications. I do not claim to
know any of what they do with it. It's worthless for tactical real-time
data, darn-it. However, Utah is using it under the wing of real time data!
Jim
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Subject: a few basic questions....
From: "Daron J. Wilson" <daron@wilson.org>
Date: Sun, 20 Apr 2003 14:43:25 -0700
X-Message-Number: 29
I'm relatively new to APRS, but not new to digital modes and amateur
radio.
As I read the posts going through and now look at the stations on the
air a bit, I am somewhat confused about what APRS is supposed to do.
1. Automatic Position Reporting System as I understand it, so why do so
many home stations (who obviously are in the same place all the time)
beacon endlessly with their position? What is the benefit of this?
2. The weather data is very interesting, and I have a home weather
station putting data on the internet already. But then I got to
thinking, if we are concerned with channel crowding, what roll in
Automatic Position Reporting do fixed weather stations provide? Perhaps
it would be better if they output their data on the packet network or a
dedicated weather network and then it were picked up since their
position doesn't change?
3. I'm unclear on the RELAY vs. WIDE setting. Lets say that I can hear
two WIDE digi's and three RELAY stations, and I have my tracker set to
transmit RELAY,WIDE2-2. Do all three relay stations attempt to transmit
my packet? What if I am out of range of any relay station, and I
transmit? Do the WIDE stations picking up my packet retransmit it
anyway even though it is prefaced with a RELAY? Is there any
Delay_before_retransmit type timer in the digipeater software that could
be set to different parameters? It seems like a heirarchial timing
scheme would allow the closest relay/wide digipeater to handle the
traffic.
Hopefully someone can educate me a bit on this, thanks.
73's N7HQR
Daron Wilson
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Subject: Re: a few basic questions....
From: "Spider" <spider@rivcom.net>
Date: Sun, 20 Apr 2003 16:08:59 -0700
X-Message-Number: 30
----- Original Message -----
From: "Daron J. Wilson" <daron@wilson.org>
To: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Sent: Sunday, April 20, 2003 2:43 PM
Subject: [aprssig] a few basic questions....
>I'm relatively new to APRS, but not new to digital modes and amateur
>radio.
>As I read the posts going through and now look at the stations on the
>air a bit, I am somewhat confused about what APRS is supposed to do.
>
>1. Automatic Position Reporting System as I understand it, so why do so
>many home stations (who obviously are in the same place all the time)
>beacon endlessly with their position? What is the benefit of this?
It allows others to know that they are there? The arguement about if a
stations moves or not is moot. Although it may look like a home station,
they could be acting as an I-Gate or a relay station and just choose the
House Symbol. Hopefully, stations can set the beacon times to something
that is reasonable. If you set this time to some long length of time, no
one would know you are there....and there are a few stations that do
exactly that. One of my digi's does not show up on the map! And, if you
know it's there...you might be able to digi thru it and drive the owner
nuts!
>
>2. The weather data is very interesting, and I have a home weather
>station putting data on the internet already. But then I got to
>thinking, if we are concerned with channel crowding, what roll in
>Automatic Position Reporting do fixed weather stations provide? Perhaps
>it would be better if they output their data on the packet network or a
>dedicated weather network and then it were picked up since their
>position doesn't change?
Think of the total collective picture. Take your grid square for
example....how many 'anything' do you have in your grid square?
Anything...Houses, objects, items...anything. Even on Firenet! Does what
is showing in your grid square represent the enviroment to any major degree?
I think you will notice hardly anything
is truely represented in your own grid square. I use the grid square
approach to show that APRS and the data that is there now is nothing
compared to what it could be. The ability is there! The technology is
there....the attitudes and the rules Hams have to live by do nothing but
hurt the ability of APRS.
If the postions were not reported, you could not know where they were at.
Let's say you were driving down the freeway and because you noticed the
weather, right where you are at that given time,
was getting bad...and indicators....like cars coming the other direction had
their lights on, dragging tree limbs behind them, dark skies ahead, etc.,
you look at your ever reliable APRS map and you look at...let's just say 5
weather stations that are 20 miles from you in the direction you are
heading.
And they were showing gusts of 150 miles an hour and loads of rain, would
you continue( okay...let's assume you are not a storm chaser)?
That is what they could provide. You would know that there was something
seriously wrong ahead and that maybe you should not continue....the data
does not have to be exact, but you would know something is up as you just
ingested several pieces of the total picture. A. Car with lights on. B.
Cars dragging tree limbs. C. Weather getting bad right were you are. D.
Dark skies ahead. E. Flaky APRSWXNET weather stations are reporting very
high winds and loads of rain.
Collectively, your instincts are telling you there is trouble ahead with the
all the data you've just ingested. As I keep preaching, how you ingest that
data is your choice! And another one...MORE IS BETTER. Your Brain can do a
better real time assessment of data than any QC rating...but that is good
data too!
Now, if you are a storm chaser, none of this applies.....it would just get
you more excited! ;)
Most of these weather stations on the air are not about getting the reports
to the APRSWXNET and they are not about following some standard they can't
meet in the first place. They are about a personnal interest one has in the
weather and Ham Radio and Weather Nuts go hand in hand. APRSWXNET collects
this data and gives these guys a way to compare or "rate" their personal
stations with the best of them. If anyone, including the NWS chooses to
look at this data...hey, that's a plus!....and you know what? The APRSWX
stations do a darn good job.
Check out FireNet if you are interested in WX data. firenet.us port 2023
for the full feed.
There is loads of provisional wx data there and much of it is as real-time
as we can get it.
Check out WWW.SEAOFBLUE.NET too!
I think many people the first get on APRS have the same exact questions. I
did. But as time goes on you come to realize that this data is not
something
that you are suppose to stare at all day long. Any data that is there is
for you to ingest any which way you choose. Someone, because it's a hobby,
has their station on the air for a reason and are enjoying it in someway or
another.
As time goes on....your ingestion process will change!
One final comment...then I'll shut up....
When a company builds a network....and over time the network begins to show
signs of overload, what do they do? They get with the program and design
additions so that their network will grow and be healthly, they invest in
their network.
What do many hams do? I've seen this since the first day of packet in So
Cal. First, they build their little network and become gods. When it
overloads they whine like it's the end of the world and tell everyone it's
the fault of the users. They then become control freaks and start placing
limits on things. Instead of "growing" their part of the network, they
hinder it to the point it's worthless. Add a channel, add a backbone, lower
a high node, teach a class, but dont whine to me as a user for cluttering
the channel...it's not yours! This is not directed at you...just
conversation. So, there really is not an overload problem anywhere except
in the minds of those who do nothing to make it better. I am not saying
dis-respect your neighboring hams
<this soapbox switch wont turn off! Darn>
73 Jim
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