A GPSDO is not hard to make. All you need is some way to compare the phase of two signals, an XOR gate can do that. Then a small $2 process moves the control voltage on the crystal. I tried one to build the simplest GPSDO that could still work. Got the parts count down to about four or five and the cost well under $10 plus the OXO which was about $20. The simplest dumb one I could make keeps about e-10. Not great but enough for many uses. I compared to my Thunderbolt and I could see the phase advance and retreat. Just a little most sophistication and I likely could do much better but my goal was to prove to myself that a GPSDO could be build VERY simply with cheap parts
On Fri, Mar 10, 2017 at 1:39 PM, al wolfe <alw.k...@gmail.com> wrote: > Jeff, > I have been using a TrueTime XL-AK purchased on eBay a few years > ago. It has worked flawlessly for the last five years. It seems to > work well with most amplified antennas that I have tried. Supposedly > accurate to better than 10 -12 but I have nothing to compare it to. It > will supposedly control an external oscillator. Mine has five 10 mhz. > sine wave outputs as well as IRIG-B out. > > I paid around $150 for mine, but it seems they are asking around > $500 these days. With patients they can be had for less. > > Al, k9si > > >> On 3/9/2017 3:45 AM, Jeff AC0C wrote: >>> We had a small tornado come through north of our house about 1/2 mile on >>> Monday. Really did a number on the antennas. Only electronics impacted >>> was my old Nortel GPSDO. It’s pretty much deaf now, as far as I can tell. >>> The Nortel always had a hard enough time obtaining the initial lock in >>> the past on startup, but since “the event” it’s been no joy. >>> >>> So I’m in the market for a GPSDO. Key application here is as a bench >>> precision frequency reference. Something with good composite noise >>> performance close in. >>> >>> If you have a suitable GPSDO in solid operational condition, kindly >>> contact me off list. Thanks! >>> >>> 73/jeff/ac0c >>> www.ac0c.com >>> alpha-charlie-zero-charlie > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.