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Discussion of precise time and frequency measurement

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GPSDO versus GPSPLL

E
EWKehren@aol.com
Mon, Oct 20, 2014 9:27 AM

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
free.
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

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 free. 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