That re trace result is impressive. Thanks for sharing that. Looking forwards to getting my hands on one.
Sent from my iPod On 2012-01-12, at 3:04 PM, [email protected] wrote: > I hear all these ideas from paper tigers. How about building something and > report on it. I can do a Shera for $ 40 and add a $ 20 GPS. And it works. > I did fail to mention that I also have retrace data. Over the test period I > had at least 10 power outages from seconds to a couple of hours. The Rb > goes right back to 1 E-12. It would be nice if some one independent does a > test on aging, maybe I was lucky and got a particularly good unit. > Bert Kehren > > > In a message dated 1/12/2012 12:04:03 P.M. Eastern Standard Time, > [email protected] writes: > > I plan to lock my FE5380 to a GPS also. But I want to mine to "unplug > able". The idea is to connect the GPS and let it sync for some > period of time. Perhaps hours or maybe weeks, the longer the better > and then you can disconnect the GPS and the FE5680 free runs at that > frequency. Plug it back in to sync it. > > I think it's clear that a small micro processor is required or a > desktop computer could be used. The FE5680 uses the RS232 port for > frequency adjustment you are going to need a computer. I think a Tiny > AVR would do fine. It is a $2, 8-pin chip. It has a 10-bit A/D > converter to read the phase offset and you can use another pin for > serial output to the FE5680. If you used a digital phase detector > you'd not need the A/D. > > The controller would work like the typical GPSDO controller except > the DAC is physically inside the FE5680. This make it easier. > > Physically, It will be mounted inside a steel box about the size of a > shoebox (The box once held a pair of large sized disk drives, from > back in the days when drives where about 3" thick) There is a thick > aluminum plate the divides the box vertically. the FE5680 sits on top > of the plate, a heat sink is bonded to the underside of the plate. A > low speed fan moves air through the box slowly. The fan is > controlled by a temperature sensor bonded to the plate the FE5680 is > mounted on. This is a crude type of "oven" using the FE5680 is a > heating element. I hope to stabilize temperature to about 2C. > I'll start with a simple comparator chip as a on/off fan controller > and eventually use another 8-pin uP to do a full PID controller with a > three wire fan > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
