[time-nuts] Odetics 325 - Lots of Details and Files!

Bruce Lane kyrrin at bluefeathertech.com
Sun May 13 14:05:59 EDT 2007

	Before I get started, I want to make it known that what I'm about to post would not have been possible without the kind efforts of Art Sauer (Magellan), Andre Sprong and Tim Gavin (FEI-Zyfer), and Robert Atkinson and Rob Kimberly (time-nuts members). You all have my heartfelt thanks for the info you provided!

	This goes out to all owners, present and future, of the Odetics 325 and 425 GPS clocks.

	INSTRUMENT REVISIONS: The 325 came in two (as near as I can determine) revisions. The original unit employed an Odetics-branded GPS receiver, while the later revision employed a Magellan OEM 5000 series module as a retrofit. Said retrofit also involved a change in firmware. 

	EPROM image files of the last known release of firmware, which allowed use of the Magellan retrofit and effectively converts an Odetics 325 to a 425, are available from my FTP archive site. This should allow anyone with an older unit, one which may not be functioning correctly, to at least get it one step closer to 'usable.'

	RECEIVERS: The Magellan OEM 5000 series is, as one might imagine, long since discontinued. However, thanks to Art Sauer, a ZIPfile of the 5000's technical manual and specifications is also available from my site.

	I was, at one time, making efforts to get a 'modern' (as in NMEA-speaking) module to work with the Odetics. However, I have found that doing so will likely require design and interfacing skills greater than mine currently are. I have found that the receiver talks to the main board in plain ASCII, at 9600-n-8-1.

	When I originally got my 325 in December of 2006, I found that it had the problem of not receiving the GPS satellites at all. After many hours of troubleshooting, I did what I should probably have done right off the top: A close physical inspection of the GPS receiver board, paying particular attention to the quality of soldering on the pins of the surface-mount devices. Surprisingly enough, I found several spots where the soldering looked suspect at best.

	I decided to try using an Ungar 6966C miniature heat gun, and its narrow nozzle accessory, as a crude sort of 'reflow' tool, applying heat as evenly as I could all around the SMD IC packages and a few other components. I let everything cool, and put it all back together -- and it started working like a champ, and has continued to do so ever since! After minor tweaking of the OCXO, the time and frequency outputs both locked on, and there has been no sign of malfunction to date.

	This particular 325 has some cool history behind it as well. It was part of the AST/RO radio-astronomy project at the south pole. I came by it thanks to a friend of mine who was working on a different project there at the time. It was offered to him (it was originally slated for disposal), and I later made a deal for it.

	In any case: Accessing my FTP archive is a bit tricky. If you're using a web browser, put the following in the URL address bar:


	If you're using a standard FTP client program, set your transfer mode to PASSIVE, and manually set the port to 50021. This is a change I made to clean up log clutter due to script kiddiez looking for wide-open (in the abusable sense) FTP sites.

	The path you want is: /electronics/radio/GPS (case-sensitive).

	Happy tweaking.

Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
"If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"

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