[time-nuts] Trimble TB replacement options???

[Bob Stewart]

Hi Chris,

You could try VE2ZAZ's board.  Pick your oscillator.  Pick your receiver.  I'm working on a rewrite of the code.  Dave Platt stepped in to add an integrator to the control system.  My latest (to be released) version looks like a significant improvement over my released version.  I wouldn't put what we have into the commercial grade category, but it is very good for the hobbyist.  The biggest thorn in my side has been the +/- 52ns jitter from the Motorola Oncore receiver.  Dave and I have that licked about as well as one can on a 40MHz PIC.  Using an Adafruit or something else with a smaller sawtooth would probably be a good idea.  In fact, I'm using an Adafruit as my comparison receiver.  One note: if you do get Bert's board, consider getting an 18F2320 chip for future releases.  Dave and I are very near the program size limit on the 18F2220.  If I decide to add code for a thermometer that will probably push it over.

Bob - AE6RV





>________________________________
> From: Chris Albertson <albertson.chris at gmail.com>
>To: wb4gcs at amsat.org; Discussion of precise time and frequency measurement <time-nuts at febo.com> 
>Sent: Saturday, October 12, 2013 10:54 AM
>Subject: Re: [time-nuts] Trimble TB replacement options???
> 
>
>What is needed now is a easy to assemble DIY GPSDO.  In the past people
>lost interest in such becuase you could buy a TB for $90.  I'd think today
>now that we have $10 microcontroller boards that have USB connections and
>are self-programming we could make a GPSDO controller with justone of those
>boards and two cheap chips (plus a GPS and XO.)
>
>