[time-nuts] Advise on building a DIY GPSDO?

[dlewis6767]

Lots' of help herein; ...but,  also lots' of nay-sayers, too.

Don't let the nay-sayers scare you.  

A VERY accurate, newbie-based, GPSDO can be built with minimal
investment or cost.

It's not hard at all.  Just Do-It.  Mistakes allowed.

I have built two GPSDO's from scratch.  Both worked very well against
each other measured with an HP 5370B; against my rubidium; as well as
my cesium.

Just look at it at the 'building-block' level. (no real need for an
embedded computer unless you like code more so than dips.  :-)


1.  Get a good, used, GPS receiver with a 10Khz output.
2.  Get a good, used, 10MHz OCXO with a voltage control.
3.  Design a simple divide-by-thousand divider.
4.  Exclusive-or these two using a 4046 PLL (comparator 1)
5.  Design a voltage tracking / filter to match the OCXO control
requirements.
6.  And, ...ta-dah;  
7.  You have a 10MHz, bench frequency standard that will rival all
others; and the best part....you designed and built it!
8.  NOTE:  Take the unused, SR flip-flop output of the 4046 PLL and
connect a small, analog, milliampmeter.  It will swing back and forth
trackin the XOR function until your GPSDO 'locks'; then become
stationary.

Basic? Yes!  Over-simplified?  Probably.  

But it will work and you will feel like you accomplished your goal of
'doing-it-yourself'.

-Don
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-- 
dlewis6767 <dlewis6767 at austin.rr.com>