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ZL3AI  > APRDIG   13.07.04 21:06l 201 Lines 6993 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Jul 09, 2/2
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From: ZL3AI@ZL3VML.#80.NZL.OC
To  : APRDIG@WW

Subject: Re: How fast can you transmit APRS ?
From: "Curt, WE7U" <archer@eskimo.com>
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
using.

--
Curt, WE7U			         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!"

----------------------------------------------------------------------

Subject: Re: How fast can you transmit APRS ?
From: "Scott Miller" <scott@opentrac.org>
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.

Scott
N1VG

----------------------------------------------------------------------

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

>>><wes@johnston.net> 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...

thanks
Bob

----------------------------------------------------------------------

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

APRSdom:

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 <archer@eskimo.com>
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
better.

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 http://www.findewe.com/nwaprs/SearchAndRescue 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
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!"

----------------------------------------------------------------------

Subject: Is any one using an ALINCO DR 620 on APRS ?? Mine won't work .
From: "Peter Jurgens" <jhp@telus.net>
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 <deni@dwatt.com>
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.

Thanks
Deni

----------------------------------------------------------------------

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.

73s,
Eric KF4OTN
kf4otn@amsat.org

---

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