Hi If you are fairly deep inside a building, GPS isn’t going to get there. WWVB likely will make it to an internal location.
If you are convinced that WWVB is un-jamable and that GPS is easily jammed, WWVB would be more robust. That’s about it. Bob > On Dec 31, 2018, at 7:56 PM, Wayne Holder <wayne.hol...@gmail.com> wrote: > > While reading this thread and pondering whether to buy and fool around with > an ES100-based module from Universal Solder, I suddenly found myself > wondering if there was any advantage to using the time received from WWVB > vs just using an inexpensive GPS receiver. The ES100 module costs about > $70, but I can get a GPS receiver, with antenna, for far less than that and > I've had no trouble receiving GPS signals indoors with most modern receiver > modules. > > I suppose the low power requirements of the ES100 might be an advantage > when building battery powered clocks to mount on the wall, but it seems > like some of the newer, ultra low power GPS modules intended for use in > smart watches could also work in a battery-powered wall clock, especially > if the receiver was only powered on a few times a day to update the time. > > And, finally, if GPS modules are (or will some become) a suitable > replacement for WWVB receiver modules, do we really need WWVB in the modern > age? Perhaps there's some critical advantage to using WWVB to get the time > but, offhand, I cannot think of it. What am I missing? > > Wayne > > On Mon, Dec 31, 2018 at 4:30 PM Brooke Clarke <bro...@pacific.net> wrote: > >> Hi Joseph: >> >> Thanks for the patent link. I've added it to my WWVB phase modulation >> info at: >> https://prc68.com/I/Loop.shtml#La_Crosse_UltrAtomic >> >> -- >> Have Fun, >> >> Brooke Clarke >> https://www.PRC68.com >> http://www.end2partygovernment.com/2012Issues.html >> axioms: >> 1. The extent to which you can fix or improve something will be limited by >> how well you understand how it works. >> 2. Everybody, with no exceptions, holds false beliefs. >> >> -------- Original Message -------- >>> On Mon, 31 Dec 2018 12:00:02 -0500, time-nuts-requ...@lists.febo.com >>> wrote: >>> >>>> time-nuts Digest, Vol 173, Issue 44 >>>> Message: 7 >>>> Date: Mon, 31 Dec 2018 04:04:22 -0800 >>>> From: "Tom Van Baak" <t...@leapsecond.com> >>>> To: "Discussion of precise time and frequency measurement" >>>> <time-nuts@lists.febo.com> >>>> Subject: Re: [time-nuts] More ES100 WWVB Measurements >>>> Message-ID: <96BB388753294278A9CDE96C1EA7D9AE@pc52> >>>> Content-Type: text/plain; charset="UTF-8" >>>> >>>> Hi Graham, >>>> >>>> That's very nice work. And you have uncovered several unusual effects >>>> in the ES100. Bugs? Features? If we time nuts keep up the good work >>>> to evaluate this chip, we are likely at some point to get an >>>> informative response from the guys who designed it. They read >>>> time-nuts. >>> I didn't see this mentioned, but I think I have found the relevant US >>> patent application: US20130051184A1, Real-time clock integrated circuit >>> with time code receiver, method of operation thereof and devices >>> incorporating the same, Oren Eliezer et al, Oren Eliezer et al, filed >>> 2013-02-28. >>> >>> .<https://patents.google.com/patent/US20130051184> >>> >>> Found this by chasing stuff from the EverSet website: >>> .< >> http://everset-tech.com/wp-content/uploads/2014/11/ReceiverRadioClocks.pdf >>> . >>> >>> Joe Gwinn >>> >>> >>>> So now both you and Tim have observed the off-by-one-second (or >>>> off-by-N-seconds) effect in the ES100. I wonder if this explains why >>>> some of my ES100-based La Crosse 1235UA Ultratomic wall clocks are >>>> off by a second sometimes. >>>> >>>> My main question: in your "Time Plot.PNG" plot, what is the cause of >>>> the sawtooth pattern? The points are almost all on a clear negative >>>> slope, though bounded by roughly +/- 75ms. Looking on the far left, I >>>> see a time drift of +50 ms to -25 ms over an hour, which is >>>> equivalent to a -20 ppm frequency offset; about -2 seconds/day. >>>> >>>> Do you think this is due to the 16 MHz onboard xtal? If so, how about >>>> changing the temperature of the eval board by a lot (say, several >>>> tens of degrees) for an extended time (say, 4 hours) and see if the >>>> sawtooth slope changes convincingly. >>>> >>>> Also, just to be sure, can you put a known independent timing signal >>>> (e.g., GPS/1PPS) into your complex BeagleBone Black / Debian 9.4 / >>>> ntpd time server / Python 3 / Excel stack to establish the validity >>>> of your measurement methodology? Very likely you did it right, but I >>>> always cringe when I hear "Linux" or "NTP" and "precise time" in the >>>> same sentence. Yes, sorry, forgive me; I grew up in the "trust, but >>>> verify" generation [1]. It applies pretty well to metrology also ;-) >>>> >>>> /tvb >>>> >>>> [1] https://en.wikipedia.org/wiki/Trust,_but_verify >>>> >>>> >>>> End of time-nuts Digest, Vol 173, Issue 44 >>>> ****************************************** >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
