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ZL3AI  > APRDIG   13.07.04 22:06l 201 Lines 6993 Bytes #999 (0) @ WW
BID : 3577-ZL3AI
Subj: TAPR Digest, Jul 09, 2/2
Sent: 040713/1943Z @:ZL3VML.#80.NZL.OC #:27812 [Chch-NZ] FBB7.00i $:3577-ZL3AI

Subject: Re: How fast can you transmit APRS ?
From: "Curt, WE7U" <>
Date: Fri, 9 Jul 2004 12:35:32 -0700 (PDT)
X-Message-Number: 20

On Sat, 10 Jul 2004, Andrew Rich wrote:

>Has anyone tried on simplex tests to see how fast you can transmit packet ?
>Has anyone wound the tinytrak up as fast as it will go ?
>My GPS will update every 2 seconds.
>Imagine a rac car, or a a jet.
>How fast is the fastest 1200 baud transmission ?

You can get down to 100ms or so TXD if you're using a crystal radio,
perhaps a bit less.  If the unit is on a special frequency and can transmit
continously, you get rid of the TXD time and can send packets back-to-back.

There are GPS'es available that can update their position at a 10 Hz rate.
Might be others that can go faster.

Shortest packets you can do still are Mic-E packets, but you could go with
a separate protocol if you only have one station on the air transmitting
continously, just sending the lat/long coordinates (and perhaps
course/speed), skipping the rest of the packet, including the header.  Just
have to meet the emissions and ID requirements for the frequency you're

Curt, WE7U		
"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!"


Subject: Re: How fast can you transmit APRS ?
From: "Scott Miller" <>
Date: Fri, 9 Jul 2004 12:39:24 -0700
X-Message-Number: 21

>Has anyone tried on simplex tests to see how fast you can transmit packet?

802.11g is pretty fast... what are you considering 'packet'?

>Has anyone wound the tinytrak up as fast as it will go ?

Are you talking about beacon interval?  I could probaby set my OpenTracker
to send a continuous stream of packets... useful for things like model
rocket tracking, but not likely to make you many friends on 144.39...

>My GPS will update every 2 seconds.

The Garmin GPS 16 will do 5 updates per second...

>How fast is the fastest 1200 baud transmission ?

Umm... 1200 bits per second?  With full AX.25 headers, you can probably
manage three APRS position packets per second.



Subject: Re: migration to 9600/70cm
From: "Robert Bruninga" <>
Date: Fri, 09 Jul 2004 17:16:23 -0400
X-Message-Number: 22

>>><> 7/9/04 1:54:02 PM >>>
>The idea of a digipeater caching objects and transmitting 
>them at later times wasdiscussed recently here...
>... it needs to be coordinated between the station being 
>cached and the digipeater so that stations can eventually 
>expire... but you probably intended that anyway.

Yes, just to clarify.  The discussion was ONLY about OBJECTS.  Never any
intention of caching stations. I used the term "bundeling" not cacheing.
That is, as much as a say 2 second delay to see if several 9600 baud
packets can be combined into one TXD bundle...



Subject: Super Tiny DIgipeater
From: "Robert Bruninga" <>
Date: Fri, 09 Jul 2004 17:33:18 -0400
X-Message-Number: 23


I understand that the TNC-X pic TNC is now working?

What woiuld it take to make it a DIIGPEATER (very simple, just respond to
WIDE)... If we can make it work, then I may have several small CUBESAT
builders that would fly us some more digipeaters in space.

These 4" cubesat satellits have no room for a full sized TNC, and most use
a MIM module to transmit GPS or Telemetry in APRS format, but they dont
have any receiver.  If we could add a receiver, then we would have a SPACE
digipeater...  And lots of them on a continuing basis...

Also we still need a TINY 1 W 2m transmitter. Has anyone tried to reverse
engineer the old AGRELLO postage stamp APRS transmitter?

de Wb4APR< Bob


Subject: Re: TNC's
From: Curt Mills <>
Date: Fri, 9 Jul 2004 17:47:30 -0700 (PDT)
X-Message-Number: 24

On Thu, 8 Jul 2004, Peter Maxfield wrote:

>With all the TNC's out there for sale, how does one new to aprs, such as
>myself, find out which tnc's can be used successfully for aprs?

Depends on what you mean by "used for aprs"...

If you're talking about a home station, nearly any old TNC will do that has
a serial port.  If it has KISS mode in it as well (most do), so much the

If you want something that can be used while mobile without a PDA or
computer attached, then the choices get more limited.  For that you'll need
a TNC that is APRS-capable.  If you just want to transmit and not receive,
you can use things like TigerTrak's, TinyTrak's, and PocketTrackers to do
it.  See for links to these
(near the bottom of the page).

If you want something to be used on a mountaintop, then probably the
Kantronics KPC-3+ is one of the better choices, as it handles
WIDEn-N/TRACEn-N flooding protocols properly.

I use an old AEA PK-88 TNC at home, and TinyTraks, PocketTrackers, and
OpenTrackers while mobile/portable.

Curt, WE7U.				archer at eskimo dot com
  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!"


Subject: Is any one using an ALINCO DR 620 on APRS ?? Mine won't work .
From: "Peter Jurgens" <>
Date: Fri, 9 Jul 2004 20:13:19
X-Message-Number: 25

I was wondering if any one else has tried using the new ALINCO DR 620 with 
the EJ-50U TNC board on APRS . I have not been able to find out how to 
program the EJ-50U for APRS use. ( Beackon, call sign , ect..... ) Alinco 
did not answer my questions and the dealer I purchased the radio from said 
they had never tried it themselves although the advertising states it is 
easily used on APRS. It would be helpful if I found somebody that is 
actually using a DR 620 on APRS successfully. Jurgen , ( Ve7Jkp ) Thanks.


Subject: Symbols
From: deni <>
Date: Fri, 09 Jul 2004 20:28:24 -0500
X-Message-Number: 26

Someone please head me towards a list of symbols.  I can not stand seeing 
myself as a little red car, when I actually drive a suburban.



Subject: RE: Symbols
From: "Christensen, Eric" <CHRISTENSENE@MAIL.ECU.EDU>
Date: Fri, 9 Jul 2004 21:37:16 -0400
X-Message-Number: 27

All symbols are listed in the APRS SPEC at the end.




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