Looks like the signal has to be with in 1 hz. I new it was tight. Need a bit more experimentation across the several receivers though they all use the same approach with a sharp Xtal filter.
On Sat, Aug 25, 2018 at 8:24 PM, paul swed <[email protected]> wrote: > My mistake the chronverter uses a pic 12f1840. > > On Sat, Aug 25, 2018 at 8:23 PM, paul swed <[email protected]> wrote: > >> Have to look at what oscillators and crystals I have then a divide. >> Thats old style and most likely the junk box has everything. >> Have to look in my box of tricks as I built several chains for the >> de-psk-er experiments. >> Have to agree on the micro the chronverter uses a pIC 12F64 as I recall >> and it has quite a nice set of dividers in it. Just not an external crystal >> input so a better oscillator can be used. Getting lazy these days. >> I have some number of tcxos from a company called vectron. Several cards >> of each. Can't imagine how I came by those. >> :-) Believe the lowest freq was 12 MHz. >> Regards >> Paul. >> >> >> On Sat, Aug 25, 2018 at 8:07 PM, Bob kb8tq <[email protected]> wrote: >> >>> Hi >>> >>> A pretty simple modest Q tuned circuit on the output of a gate will turn >>> the square wave >>> into a sine. Not much to it since there are a lot of power supply >>> components out there that >>> work fine at 60 KHz. In order to get a stable 60KHz, a divider is the >>> way to go. I’d probably >>> use one that’s built into an MCU as part of a timer or something >>> similar. >>> >>> Bob >>> >>> > On Aug 25, 2018, at 7:00 PM, paul swed <[email protected]> wrote: >>> > >>> > Bob The generator sig is 60 Khz sinewave.but as a I build up a divider >>> > chain and such your idea makes great sense. >>> > Then filter to 60 KHz. >>> > But I see the issue with the Chronverter carrier its 120-150 Hz high. >>> > Bounces around a fair amount. >>> > There could be a secondary issue in that the carrier may not actually >>> be >>> > phase stable. >>> > It really doesn't matter as for the Truetimes and Spectracoms its >>> simply >>> > not good enough. >>> > I still need to try the cheapy clocks as that is what it was intended >>> for. >>> > Not throwing stones as so much of what it does saves me a bunch of >>> coding >>> > and doing exactly what Dave did. >>> > Regards >>> > Paul >>> > WB8TSL >>> > >>> > On Sat, Aug 25, 2018 at 5:31 PM, Bob kb8tq <[email protected]> wrote: >>> > >>> >> Hi >>> >> >>> >> You can do the 14 db deep modulation with a tristate gate and a pair >>> of >>> >> resistors. >>> >> Ground the input and feed the “modulation” signal to the tristate >>> control. >>> >> >>> >> Bob >>> >> >>> >>> On Aug 25, 2018, at 4:35 PM, paul swed <[email protected]> wrote: >>> >>> >>> >>> From the earlier threads OOK modulation does not work for high end >>> clocks >>> >>> like spectracoms and truetimes. Have not tried it on the cheapy >>> clocks >>> >> yet. >>> >>> >>> >>> I added an external modulator. A dg419 analog switch and then with a >>> few >>> >>> resistors added DC offset and anttenuation so that the carrier drops >>> by >>> >> -14 >>> >>> db per the wwvb spec. The logic control is driven from the >>> chronverter >>> >> and >>> >>> it totally works. Spectracom Netclock 2 locked up in the normal time. >>> >>> There are far better modern single supply analog gates that will >>> work. >>> >> Just >>> >>> did not have any. >>> >>> >>> >>> The 60 KHz carrier is supplied by a fluke 6060 generator. This >>> eliminates >>> >>> any chance of being off frequency and is not the long term answer. >>> >>> >>> >>> The chronverter actually uses a dallas semiconductor clock chip thats >>> >>> reasonably accurate.(dangerous to say on time-nuts) So that even if >>> you >>> >> do >>> >>> not add the GPS receiver it will run quite some time correctly after >>> >>> setting the time. >>> >>> >>> >>> Chronverter draws 6 ma from a 5 V supply. I always like low power. >>> >>> >>> >>> All in all a very nice answer to what do we do if WWVB goes away. >>> >>> As mentioned it handles timezones and DST and you can change DST if >>> those >>> >>> silly politicians screw with it again. >>> >>> >>> >>> Speculation >>> >>> The chronverter actually puts out carriers for the popular LF >>> stations >>> >>> along with the time codes for them. >>> >>> >>> >>> Though the modulator allows quality clocks to lock I speculate the >>> >>> frequency from the chronverter is not tight enough. All of these >>> clocks >>> >>> have very sharp crystal filters in them. 10 Hz. Plan to measure the >>> >> output >>> >>> of the chronverter see what the 60 KHz is actually at. Though >>> listening >>> >> on >>> >>> a HP3586 receiver it appears pretty close to frequency maybe its >>> just not >>> >>> good enough. Or the fact is OOK modulation does not work because it >>> gaps >>> >>> the PLL in these clocks. >>> >>> >>> >>> Next steps >>> >>> >>> >>> - Determine and lay to rest the OOK/need for external modulator. >>> >>> - Power amplifier and loopstick transmitting antenna staying at or >>> >> below >>> >>> 30uv@30 meters. >>> >>> - Integrate a neo6 GPS receiver in. (Seriously easy) >>> >>> - >>> >>> - Box it up. >>> >>> >>> >>> Have my eye on one of the Truetime DC468 units and the classy >>> panelplex >>> >>> display. >>> >>> >>> >>> Hope this helps those of you concerned with what to do should WWVB go >>> >> away. >>> >>> Regards >>> >>> Paul >>> >>> WB8TSL >>> >>> _______________________________________________ >>> >>> time-nuts mailing list -- [email protected] >>> >>> To unsubscribe, go to http://lists.febo.com/mailman/ >>> >> listinfo/time-nuts_lists.febo.com >>> >>> and follow the instructions there. >>> >> >>> >> >>> >> _______________________________________________ >>> >> time-nuts mailing list -- [email protected] >>> >> To unsubscribe, go to http://lists.febo.com/mailman/ >>> >> listinfo/time-nuts_lists.febo.com >>> >> and follow the instructions there. >>> >> >>> > _______________________________________________ >>> > time-nuts mailing list -- [email protected] >>> > To unsubscribe, go to http://lists.febo.com/mailman/ >>> listinfo/time-nuts_lists.febo.com >>> > and follow the instructions there. >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to http://lists.febo.com/mailman/ >>> listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> >> > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
