Re: [time-nuts] Looking for information on True Position GPSDO.
True Position was a Berwyn, PA mobile industry equipment provider.
In 2014 they acquired Skyhook Wireless and changed company name to acquirer’s.
—
These True-Position units are surplus from the cellular/mobile phone industry.
Several years ago, when these units first appeared (2010/2011), the Mt. Airy VHF Radio Club (“Pack Rats”, Philadelphia, PA area) created a Technical Project to use these GPS units as a cheap GPSDO for amateur radio (and time-nut) users.
http://www.packratvhf.com/index.php/technical-articles
A Packrat GPS Receiver Project
by Gary WA2OMY and Bruce WA3YUE
http://www.packratvhf.com/index.php/technical-articles/160-gps-receiver-project
This project was developed to use surplus GPS receiver boards to provide a precision 10 MHz reference for the ham community using equipment that accepts a 10 MHZ reference or clock. We hope to have accomplished this at a reasonable cost to the community.
Project PDF (31 pages, extensive photos for beginner DIY / Maker)
http://www.packratvhf.com/attachments/article/160/A-Packrat-GPS-Receiver-Project.pdf
The Internet Link (above) has the necessary HEX files with or without Display,
as well as PDF of the Club’s Powerpoint presentation. The Mt. Airy club NO LONGER have surplus TruePosition units, as this club project was 7-8 years ago.
MANY Asian eBay resellers are NON-STEM,
relying on Mt. Airy project and other published documents to determine $$ surplus value.
Greg, w9gb
Date: Sun, 18 Mar 2018 09:59:08 -0500
From: John Green wpxs472@gmail.com
Subject: [time-nuts] Looking for information on True Position GPSDO.
There is a small, about 3.5" by 4.5", GPSDO board being offered by several
sellers on eBay. I bought one from what looks to be the only US based
source. It is identified as True Position, Inc., and had a small CTS OCXO
and Furuno GT8031 on board.
Sent from iPad Air
John -
I would NOT bother with trying to replace the 10 MHz oscillator.
Spend your $$ for the inexpensive Arduino board, LCD, 5 volt antenna, and nice enclosure .... that will provide you with a “self-running” GPSDO unit (operator intervention not required to operate).
The fact that Mt. Airy has already provided the Arduino “firmware” (HEX) is a BIG plus — IF you have no coding experience.
In addition, you should change to Google for Internet searches, and routinely post purchase queries to focus groups, like time-nuts, before blindly purchasing on eBay.
That is the “smart approach”, that saves time, $$ and get what you desire.
Greg, w9gb
Date: Sun, 18 Mar 2018 09:59:08 -0500
From: John Green wpxs472@gmail.com
To: time-nuts@febo.com
Subject: [time-nuts] Looking for information on True Position GPSDO.
This isn't a bad looking little board.
I was thinking of pulling the little CTS oscillator and replacing it with something better.
The fact that you have to tell it to do its thing is something of a bummer,
but I think I can live with it.
Hi
If you do go swapping around OCXO’s (or whatever) on a GPSDO board,
it’s very nice to be able to change the internal “magic numbers” to get the
control loop running properly again. The TBolt kind of spoiled us all in that
regard. Most GPSDO’s are not very user friendly in this regard ( = you can’t
get at the numbers you need to change).
Bob
On Mar 19, 2018, at 1:01 PM, Gregory Beat w9gb@icloud.com wrote:
John -
I would NOT bother with trying to replace the 10 MHz oscillator.
Spend your $$ for the inexpensive Arduino board, LCD, 5 volt antenna, and nice enclosure .... that will provide you with a “self-running” GPSDO unit (operator intervention not required to operate).
The fact that Mt. Airy has already provided the Arduino “firmware” (HEX) is a BIG plus — IF you have no coding experience.
In addition, you should change to Google for Internet searches, and routinely post purchase queries to focus groups, like time-nuts, before blindly purchasing on eBay.
That is the “smart approach”, that saves time, $$ and get what you desire.
Greg, w9gb
Date: Sun, 18 Mar 2018 09:59:08 -0500
From: John Green wpxs472@gmail.com
To: time-nuts@febo.com
Subject: [time-nuts] Looking for information on True Position GPSDO.
This isn't a bad looking little board.
I was thinking of pulling the little CTS oscillator and replacing it with something better.
The fact that you have to tell it to do its thing is something of a bummer,
but I think I can live with it.
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