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ZL3AI > APRDIG 11.05.07 10:49l 222 Lines 7726 Bytes #999 (0) @ WW
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From: ZL3AI@ZL2BAU.#79.NZL.OC
To : APRDIG@WW
Message: 11
Date: Sat, 28 Apr 2007 23:53:05 -0700 (PDT)
From: Curt Mills <archer_at_eskimo.com>
Subject: Re: [aprssig] Help for course/speed/altitude etc HF APRS
On Sun, 29 Apr 2007, Jack Chomley wrote:
>I should have looked in the manual further :-) Looks like I can run the TM1+
>in NMEA mode and simply select a transmit timer value, so it does not continue
>to broadcast EVERY sentence the TM1+ gets from the GPS.
Yea but: Check out the length of a GPRMC or GPGGA sentence compared to the
length of a normal APRS sentence. Now check any of those against Base-91
Compressed or Mic-E Compressed sentences.
FWIW: The success rate of your packets getting decoded by other stations
depends greatly on the length of those packets. The shorter your packets
are, the more will be received correctly.
NMEA sentences over the air are nearly the worst packets you can send,
length-wise. I think the only ones that are worse are nice long weather
packets, or any packet with extensive comments at the end.
If the TM1+ can do Base-91 Compressed or Mic-E packets, select that
instead. If they can do Standard APRS packets instead of GPGGA or GPRMC
packets, you still win.
You might investigate getting an Opentracker 0T1x or Tracker2 to do this
instead, and use it in Base-91 mode. OT1x kits are quite inexpensive, and
the latest OT1x version added receive capability. I hope I got that model
number right!
--
Curt, WE7U. archer at eskimo dot com
http://www.eskimo.com/~archer
Lotto: A tax on people who are bad at math. - unknown
Windows: Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me: I picked the coordinate system!"
------------------------------
Message: 12
Date: Sat, 28 Apr 2007 23:56:57 -0700 (PDT)
From: Curt Mills <archer_at_eskimo.com>
Subject: Re: [aprssig] Help for course/speed/altitude etc HF APRS
On Sun, 29 Apr 2007, Jack Chomley wrote:
>In my case, the TM1+ can look for the header ($GPRMC) and I then either set
>the sentence length or termination character and it will be sent out the radio
>port at intervals set by my Tx timer value.
You originally stated that you wanted speed/course/altitude.
If you transmit the GPRMC sentence you'll only have
time/position/speed/course sent out.
If you choose GPGGA instead, you'll be sending
time/position/altitude.
Many TNC's that can send Standard APRS, Mic-E Compressed, or Base-91
packets allow you to select which of the speed/course/altitude parameters
to send, and can send them in every packet.
--
Curt, WE7U. archer at eskimo dot com
http://www.eskimo.com/~archer
Lotto: A tax on people who are bad at math. - unknown
Windows: Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me: I picked the coordinate system!"
------------------------------
[commercial content deleted]
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Message: 15
Date: Sun, 29 Apr 2007 11:19:54 -0400
From: "Stephen H. Smith" <wa8lmf2_at_aol.com>
Subject: [aprssig] Re: Help for course/speed/altitude etc HF APRS
Curt Mills wrote:
>On Sun, 29 Apr 2007, Jack Chomley wrote:
>
>
>>I should have looked in the manual further :-) Looks like I can run the TM1+
>>in NMEA mode and simply select a transmit timer value, so it does not continue
>>to broadcast EVERY sentence the TM1+ gets from the GPS.
>>
>
>Yea but: Check out the length of a GPRMC or GPGGA sentence compared
>to the length of a normal APRS sentence. Now check any of those
>against Base-91 Compressed or Mic-E Compressed sentences.
>
>FWIW: The success rate of your packets getting decoded by other
>stations depends greatly on the length of those packets. The
>shorter your packets are, the more will be received correctly.
>
>NMEA sentences over the air are nearly the worst packets you can
>send, length-wise. I think the only ones that are worse are nice
>long weather packets, or any packet with extensive comments at the
>end.
>
>If the TM1+ can do Base-91 Compressed or Mic-E packets, select that
>instead. If they can do Standard APRS packets instead of GPGGA or
>GPRMC packets, you still win.
>
>Y
The problem is that in raw NMEA mode, the TigerTrak can only send ONE
selected NMEA sentence. So again, you either send the one with
velocity/heading only ($GPRMC) --or-- you send the one with altitude
only ($GPGGA).
The TigerTrak can only send standard APRS-format posits parsed from the
$GPRMC GPS sentence (speed but no altitude data) or raw NMEA (only one
sentence at a time selectable). Thus, there is no way to send both
speed/heading and altitude at the same time with this device.
I have used the TigerTrak for years for 30M HF APRS because it would
operate at 300 baud, but was very frustrated that it wouldn't do any
kind of compressed formats. When the TinyTrak III came out that could
do 300 baud and do Mic-E format with altitude by parsing both GPRMC and
GPGGA, I started using that instead.
In fact, the two switch-selectable "modes" of the TinyTrack III can each
be set to different baud rates. One side can be set to run at 1200 baud
for VHF and the other side set to 300 baud for HF. This is very
convenient for "DC-to-light" HF/VHF/UHF rigs like the Yaesu FT-100 or
FT-817 or Icom 706 that might be used on either 2M or 30 APRS.
The success rate when transmitting the very short Mic-E packets over the
noisy, interference-prone, fading HF paths is noticeably higher than
for the longer plain-text standard APRS format. (I would would
monitor myself off the internet while triggering HF transmissions from
the car, and count the number of transmissions that actually got
successfully igated from HF to the Internet.)
--
Stephen H. Smith wa8lmf (at) aol.com
EchoLink Node: 14400 [Think bottom of the 2M band]
Home Page: http://wa8lmf.com --OR-- http://wa8lmf.net
NEW! World Digipeater Map
http://wa8lmf.net/APRSmaps
JavAPRS Filter Port 14580 Guide
http://wa8lmf.net/aprs/JAVaprsFilters.htm
"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths
Updated "Rev H" APRS http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:
------------------------------
Message: 16
Date: Sun, 29 Apr 2007 08:40:24 -0700 (PDT)
From: "Tyson S." <timbercutter_at_yahoo.com>
Subject: [aprssig] Findu Topo and Imagery
I may have missed some exchange of emails about the subject recently if
this has all ready been discussed, have not been around the Internet as
much as usual, but I have noticed for the last few months the topo maps
and the aerial images do not work on the Findu site. The error message
says "Geo file not found"
Tyson - N7ZMR
Southern Oregon
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Message: 17
Date: Sun, 29 Apr 2007 16:48:42 +0100
From: "Andy Pritchard" <apritch_at_blueyonder.co.uk>
Subject: Re: [aprssig] Findu Topo and Imagery
Try
http://www.mountainlake.k12.mn.us/ham/aprs/
Andy, M0CYP - Telford
http://www.apritch.myby.co.uk/uiview.htm
http://www.apritch.myby.co.uk/radioprop.htm
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Message: 18
Date: Sun, 29 Apr 2007 09:15:27 -0700 (PDT)
From: David Pavao <kg6sod_at_pacbell.net>
Subject: [aprssig] remove me from the list
remove me from the list
------------------------------
Message: 19
Date: Sun, 29 Apr 2007 12:33:35 -0400
From: Mark White <jmarkw_at_ec.rr.com>
Subject: Re: [aprssig] remove me from the list
David Pavao wrote:
>remove me from the list
https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
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