[aprssig] RINO Position decoding (new subj)

Wed Mar 8 21:43:19 EST 2006

>>> "Wes johnston" <wes at kd4rdb.com> 03/08/06 8:56 PM >>>
>I think the problem with the rinos is not the transmitter... 
>the probeml is twofold with receiver... squelch too tight, 
>and desense caused by close prox to GPS unit hash.

And #3 which is the receivers are 7 dB worse than
typical HAM front ends (my measurements on 3
of them)...

So putting a LNA in front of the APRS receiving
RINO should get at least that 7 dB back while also
picking up maybe 6 dB of external Antenna gain.

Wes
----- Original Message ----- 
From: "Robert Bruninga" <bruninga at usna.edu>
To: <wes at kd4rdb.com>; <aprssig at lists.tapr.org>
Sent: Wednesday, March 08, 2006 8:38 PM
Subject: Re: [aprssig] RINO Position decoding (new subj)

Yes, but what useful range do you get?  I find
I can yell almost as far as these radios work.  ?
Bob

>>> wes at kd4rdb.com 03/08/06 1:09 PM >>>
I am that "customer" ;-)

Bob, I tried to decode the data, but it was easier to set aside a rino unit
to dedicate to this function at the command post and let xastir download the
rino waypoints from the GPS portion of the radio.  Ideally, I'd love to see
a small microprocessor that had an audio input line and could decode the
rino data.... as it stands now, I have yet to find a small processor that
can deal with the 2^31 range of numbers that any garmin device uses for
coordinates.  I did find the "basic atom" that said it would do float math
up to 2^31, but it ended up with a small math error that put my positions
off by 70feet.  Since the unit was unusable for the float math part, I did
not try any further to decode the audio data.  I do know that it is 600 bits
/ sec zero crossing waveform... really this is the same info that you
discovered 4 or 5 years ago, so no progress there sorry to report.  Heck,
I'd even settle for a black box that downloaded waypoints from the rino unit
periodically, converted them to aprs objects and spit out on a serial port
to a KISS mode TNC... but alas, I run into the same floating point math
problem.

Recently there have been a few strides forward in the use of xastir and/or
rino radios.
1)last month, I finally got the GPSMAN program to run under cygwin/windows.
GPSman is a program that will download all the waypoints (among other
things) from a GPS unit and place them in a text file.  Xastir uses GPSman
to built this text file of waypoints and then transmits them on air,
typically every 1 to 5 minutes (user definable).  There had been an error in
the GPS man program that prevented it from working under cygwin.  I worked
with the author, and over a period of about 3 days, it's working fine.  I'm
not sure he has published the corrected gpsman files to his website yet.
Anyone wanting them, contact me.

2)My next step will be to improve the xastir side of things so that xastir
only transmits the objects that have moved since the last polling interval.
Things have been a little too busy at work and home for me lately to try
this.  It'll probaby be some sort of shell script that compares the last
downloaded text file of waypoints with the current, and removes the dupes
leaving only the changes.  Then xastir will parse the reduced list.

3)I have considered gutting a rino radio from the DISC on the pll chip
forward.  In other words, hooking the "brains" of the rino to the front end
of a better radio, perhaps a bat wing GMRS radio - with an external antenna.
Then we get the benefit of better antenna (RX only) and better receiver
sensitivity.

I have modded one of the rino 110 units to hook to an external antenna.  I
have not done any real field tests since the mod.  I did read in the
archives of the yahoo rino group that some guy did yagi to yagi link of
20miles, but I really doubt it.

My biggest gripe at the moment is that some GMRS repeater "one man band"
club and another fellow wrote in to the FCC during the petition period and
nixed the RINO data on GMRS channels.  Kinda nuts... you can send data on
GMRS simplex channel (ie the output of a GMRS repeater), but you can't send
data on a GMRS repeater input frequency.  The writers were afraid the data
would interfere with the GMRS repeater users... but I suppose they failed to
realize that the data is limited in time duration to 1 second and not more
than every 10 seconds (garmin observes a max data rate of one position every
30 seconds).  Or maybe they are just crotchedy old men who don't like to see
change?? 8-)
Wes

----- Original Message ----- 
From: "Robert Bruninga" <bruninga at usna.edu>
To: <archer at eskimo.com>; <aprssig at lists.tapr.org>
Sent: Wednesday, March 08, 2006 11:55 AM
Subject: Re: [aprssig] RINO Position decoding (new subj)

>>> "Curt, WE7U" <archer at eskimo.com> 03/08/06 9:43 AM >>>
>We had a user that required RINO support and
>that was the only wayto do it at the time.
>Sorry that it derailed your effort.

Sorry, didnt mean it to sound that way.  I was all
excited at yor approach and it was the best way
to get the capability.  I even bought 3 radios so
I could have two in the field and use one as the
central receiver.  But my recent sesnsitivity tests
of FRS radios in general and the RINO shows that
with 5W HT's, we can generally do 10 to 15 dB
better with HAM radios, and so I think it might be
time to go back and re-look at decoding the data
directly.

Has your customer been happy with the range
of the RINO in his application?  or did the short
range dampen his enthusiasm for the radios?

Bob
--
Curt, WE7U.   APRS Client Comparisons: 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!"

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