[OZAPRS] New option for HF 30M APRS -- TinyTrak 3b (Review)

Mon Feb 16 20:37:14 EST 2004

WA8LMF2 may have convinced Byon to use the 1600/1800 Tone pair, but
remember that the idea to add HF send capability to the TinyTrak came from
Oz - even if it took several messages to Byon to convince him how useful
it would be, and how simple a change it was !

Mike VK2BMM

-----Original Message-----
From: Richard Hoskin [mailto:lhoskin at bigpond.com]
Sent: Monday, 16 February 2004 06:38 pm
To: ozaprs at marconi.ics.mq.edu.au
Subject: [OZAPRS] New option for HF 30M APRS -- TinyTrak 3b (Review)

This is an excerpt from the US APRS Sig that I thought some readers would
be
interested in.

Cheers
Richard
VK3JFK

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

Subject: New option for HF 30M APRS -- TinyTrak 3b (Review)

From: "Stephen H. Smith" <WA8LMF2 at aol.com>

Date: Sun, 15 Feb 2004 03:50:38 -0800

X-Message-Number: 1

For the last several days, I have been beta-testing the next-generation 

firmware for the Byonics TinyTrak 3. The major enhancements in this 

next version are support for raw NMEA strings, and support for 

300-baud/200-Hz-shift HF operation. Only the contents of the PIC chip 

have changed; the new version can be inserted as an upgrade into even 

the oldest TinyTrak board. [ I did my testing on an original board 

from a TinyTrak I! ]

When the new version is released publicly (in the next week or two) we 

will have, for the first time, a device that can do Mic-E 

compressed-format Smart-Beaconed transmissions on 300 baud HF! The new 

version firmware also now provides for separate position and status 

reports. (Previous versions only transmitted a combined posit and 

status report.)

The HF tones used by the TinyTrak are, at my suggestion, the same 

1600/1800 Hz pair used by the KAM and TNC2 so the same radio frequency 

settings used with these devices will apply; i.e. for normal 30-meter 

operation on 10.149.200/10.149.400, set the SSB radio to EXACTLY

10.151.00 MHz LSB or to 10.147.60 MHz USB . As expected, these 

tones pass easily through even very narrow (1.8KHz bandwidth) SSB IF 

filters in the center of their passbands, where the group delay and 

phase shift characteristics are flattest-- something that can't be said 

for the much higher tones used by the PK-232 TNC and AGW Packet Engine 

softmodem.

The short Mic-E format bursts are a huge improvement over the (much 

longer) plain text strings the TigerTrak, dumb trackers implemented with 

TNCs, and programs on computers send. [ TigerTrak transmits the 

standard APRS "compressed" format that is plain-text ASCII and about 4 

times as long!] If your GPS device outputs the GPGGA sentence, a 

check-box option on the setup screen will cause the TinyTrak to encode 

altitude in the basic Mic-E burst.

On the constantly noisy, QRM-riddled HF freqs, the very short 

Mic-E bursts have a much higher probability of getting thru intact than 

the longer strings sent by other HF devices.

By checking the "Status, Send Separate" box, the actual posit can be a 

VERY short true Mic-E that has a very high probability of success, 

followed by a separate longer "expendable" human-readable text status 

transmission.

The new TinyTrak is now, as far as I know, the ONLY APRS device that can 

send an actual Mic-E burst on HF. This will yield a major improvment 

in reliability and throughput on HF APRS, by addressing the noise/QRM 

problem, and the limited throughput of the 300 baud channel.

The TinyTrak supports two completely different switch-selectable sets of 

parameters and settings. These variables include radio baud rate/tone 

pair, path, APRS symbol, beacon frequency, status message, encoding 

format (APRS, Mic-E or raw NMEA), and an number of other variables. 

These variables are set into the PIC's flash memory with a stand-alone 

single .EXE Windows program; i.e. TinyTrak3Config.exe doesn't need 

to be "installed" and could be carried around in, and executed from, a 

flash-memory keychain drive.

You could configure the primary set for 1200 baud VHF and the 

secondary set for 300 baud HF. With a "DC-to-light" radio like an Icom 

706, Yaesu FT-100 mobile or 817 porta-luggie, you could operate either 

144.39 or 30 meters HF as you travel with just a flip of the switch. Or 

how about a new concept -- Mic-E operation on HF SSB phone?

A final note: The TinyTrak radio interface uses EXACTLY the same DB9 

connector with the same pinout as Kantronics KPC3 and 9612 TNCs, so any 

radio interface cables you have for these devices will work as-is on the 

Tiny Trak.

Stephen H. Smith wa8lmf (at) aol.com

Home Page: http://wa8lmf.com <http://wa8lmf.com/> 

Ham Radio/Mobile SSTV page: http://members.aol.com/wa8lmf/ham
<http://members.aol.com/wa8lmf/ham> 

APRS Stuff 

http://members.aol.com/wa8lmf/aprs <http://members.aol.com/wa8lmf/aprs> 

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