[time-nuts] GPSDO versus GPSPLL

EWKehren at aol.com EWKehren at aol.com
Mon Oct 20 05:27:38 EDT 2014

Having build GPSDO's since Brooks came out with his in QST I learned a few  
things and always worked on improving its performance And hopefully the FE 
405B  project that lasted over nine month will top any thing in GPSDO's. The 
FE5680A  is nearing final Beta test and hopefully will soon be out as a 
kit. Kiting ads  to the cost, since I yet have to find one that would do it for 
Being a Ham and having many Ham friends and some time nuts are Ham's I  
decided to do what I call a GPSPLL for Ham use. With uwave activities and SDR's 
 there is interest for a low cost home brew reference.  While time nuts  
strive for 1 E-13 Hams can live with 1 E-10. The low cost ublox combined with  
there performance and 1 KHz out it all came together. Yes, using a Morions 
is an  overkill, but only because we had them and did not want to spend 
money or time  ordering parts. The team members in Australia will experiment 
with lower  performance VCXO's and release it to the Ham world.
Let us not forget the purpose of a GPSDO or GPSPLL is one thing only: match 
 GPS performance to XO performance.
But for this particular project the most important aspect is that every  
thing on the board is readily available, easy to assemble, flexible for 
multiple  GPS and XO's and shipping a board only in a regular envelop is cheap and 
so far  no problem international. Many Ham's still use a solder iron and 
meet regularly  in groups so they can order the parts economically.
Bert Kehren

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