[time-nuts] Opinion Of Attached - Possible HPSDR GPSDO 'Engine'

[Chris Albertson]

On Sat, Apr 14, 2012 at 8:00 PM, Bill Dailey <docdailey at gmail.com> wrote:

> Why not do this... Should be cheaper and offer better performance..
> Especially short tem.
>
> http://www.jrmiller.demon.co.uk/projects/ministd/manual.pdf
>
>
The short term performance of a GPSDO is defined by the short term
performance of the OCXO.  I think the proposed device that was quoted at
$300 used a TXCO, not an OCXO.   One could also use a double oven XO
(DOCXO)

One way to get good performance and low cost is to make the system modular.
 It breaks nicely into three parts
1) The GPS
2) A voltage controlled oscillator which could be a double oven OX or the
cheaper TXCO or "whatever"
3) the GPSDO controller.  As shown on the PDF file above these can be very
simple.

All GPS and most oscillators have about the same interface so an end user
could choose his parts based on budget.   If you'd build a stand alone
controller that would accept timing pluses from a GPS from 1Hz to 1KHz and
would output a voltage to control an oscillator you'd have a pretty popular
device.

The problem is the "competition".  It is hard to build anything that is
better than the Thunderbolt without spending more for parts than the price
of a Thunderbolt.

Chris Albertson
Redondo Beach, California