Paul, by going to high power mode I meant at the 200, 500, or 800 msec point of each second. Ray -------- Original Message -------- Subject: Re: [time-nuts] WWVB Dephaser Question From: Bob kb8tq <kb8tq@n1k.org> Date: Fri, October 09, 2020 4:12 pm To: Discussion of precise time and frequency measurement <time-nuts@lists.febo.com> Hi I don’t believe that the WWVB transmitters change power day to night. Both the north and south antenna’s are fed with the same power, regardless of the time of day….. Bob > On Oct 9, 2020, at 5:59 PM, rcbuck@atcelectronics.com wrote: > > Paul, > I was seeing a -10 dBm on the SA when they enter high power mode at > night. At low power they are only a couple of dB above the nearby noise > makers. But that is at the output of the last stage of my receiver. The > WWVB signal was about 10-15 dB above the noise makers in my work shop. I > don't know what the actual WWVB signal level is and have no way to > measure it. I estimate the ferrite antenna to be approx 20k ohm which > doesn't match the 50 ohm input of the SA. Maybe feed the rod antenna > into a single stage op amp with a gain of 1 to feed the SA would work > give me a rough idea?? I previously said I had 1 mV of daytime signal > according to the WWVB maps. But that was wrong. In my mind I was > thinking 1000 uV when the maps show the 100 uV coverage area. So receive > level during the day should be around 0.1 mV. I have PCB's on order that > hopefully will improve the receiver performance. > > Bob, > I'm still trying to figure out if a software or hardware solution is > better. I've looked at the Costas loop and a PLL angle. But I run into > the problem of the LO being on the same frequency as WWVB. Plus as Paul > said the math is intimidating to me. Locking WWVB to a HF oscillator and > dividing down to 10 kHz or so for the control voltage and I/Q > demodulation may be an answer but involves more hardware. > > For a software solution I don't know exactly how to approach the task. I > don't have any DSP software experience so that option is out. I haven't > made a decision on the CPU yet. I will just use whatever it takes for > the job, probably a STM32 part of some sort. I have a couple of STM32 > development boards I can use when I get to that point. > > Ray > > > -------- Original Message -------- > Subject: Re: [time-nuts] WWVB Dephaser Question > From: Bob kb8tq <kb8tq@n1k.org> > Date: Fri, October 09, 2020 12:23 pm > To: Discussion of precise time and frequency measurement > <time-nuts@lists.febo.com> > > Hi > > Since you need a MCU to decode the data, you might as well get > things in there sooner rather than later. There are a number of MCU’s > out there that have fast enough ADC’s to do the job. They do have > limited > dynamic range. You can go to one of the 24 bit converters and have > a ton of dynamic range. It’s all up to you. > > Once it’s into the MCU, it’s just code :). Depending on how much cpu > > horsepower you have (and how much code you want to write) you can > go more or less crazy …. PHK has some interesting tidbits on his web > site. http://phk.freebsd.dk/AducLoran/AducLoran-0.0.pdf > <http://phk.freebsd.dk/AducLoran/AducLoran-0.0.pdf> > > Bob > > >> On Oct 9, 2020, at 1:38 PM, rcbuck@atcelectronics.com wrote: >> >> Paul, Bob, >> >> I am not using any commercial receiver. I am building everything from >> scratch. The RF front end starts with a ferrite rod antenna feeding a >> differential first op amp followed by 5 stages of op amp filtering and >> amplification. When the last stage is fed to my spectrum analyzer >> (through attenuators) the WWVB signal is clearly visible. I'm now trying >> to figure out how to detect the phase shift so I can get the time data >> for my CPU to process and send to a display. >> >> I already have a GPS based clock that I built so I thought the WWVB >> phase clock would be an interesting project. >> >> Ray >> >> -------- Original Message -------- >> Subject: Re: [time-nuts] WWVB Dephaser Question >> From: Bob kb8tq <kb8tq@n1k.org> >> Date: Fri, October 09, 2020 7:35 am >> To: Discussion of precise time and frequency measurement >> <time-nuts@lists.febo.com> >> >> Hi >> >> At least to me, anything dimensioned in the 100’s of feet is >> “massive” compared to >> the rod antennas normally seen in WWVB use …. >> >> The other point being that if the antenna is some sort of large loop, >> it’s going to be >> a good long ways away from the receiver. You get both a larger signal >> voltage and better >> isolation ….. >> >> Bob >> >>> On Oct 8, 2020, at 11:30 PM, John C. Westmoreland, P.E. <john@westmorelandengineering.com> wrote: >>> >>> Hello All, >>> >>> Are there any design details someplace regarding these massive antennas? >>> >>> Thanks, >>> John >>> AJ6BC >>> >>> >>> On Thu, Oct 8, 2020, 19:27 paul swed <paulswedb@gmail.com> wrote: >>> >>>> Hello to the group. >>>> Ray as Bob mentions you are taking a 10s of uv signal to a logic level of >>>> maybe 4V. >>>> If the loop is any place close to the divided down signal, it will >>>> oscillate. It would take incredible shielding to protect the receiver. >>>> Thats why you often see a solution that doubles to 120 KHz and modifies the >>>> detectors to work at that frequency. That means hacking the radio >>>> internally. Not fun. The other really annoy effect is that the doubling >>>> slips phace due to noise and propagation. So if charting suddenly you get a >>>> 180 degree flip. Thats messy. >>>> The doubling solution can work. Search for carter and there are several >>>> others. >>>> But having tested and used all of the alternates and lots more on the east >>>> coast decided they were too much trouble. You should see the box of boards >>>> I have chuckle. >>>> For me I am very happy with the d-psk-r. Though in being above board I >>>> designed version 1 and Rodger and I did version 2. Its solid and no mods to >>>> any receiver. Everything has always been released to the time-nuts group. >>>> As they say have fun. >>>> Regards >>>> Paul. >>>> WB8TSL >>>> >>>> On Thu, Oct 8, 2020 at 5:39 PM <rcbuck@atcelectronics.com> wrote: >>>> >>>>> Bob, >>>>> >>>>> I am using a ferrite rod antenna for the receiver. No outside antenna. >>>>> >>>>> Ray >>>>> >>>>> -------- Original Message -------- >>>>> Subject: Re: [time-nuts] WWVB Dephaser Question >>>>> From: Bob kb8tq <kb8tq@n1k.org> >>>>> Date: Thu, October 08, 2020 12:40 pm >>>>> To: Discussion of precise time and frequency measurement >>>>> <time-nuts@lists.febo.com> >>>>> >>>>> Hi >>>>> >>>>> A lot depends on your antenna setup. You can also swamp out the incoming >>>>> WWVB signal……. >>>>> >>>>> Bob >>>>> >>>>>> On Oct 8, 2020, at 2:07 PM, <rcbuck@atcelectronics.com> < >>>>> rcbuck@atcelectronics.com> wrote: >>>>>> >>>>>> I have read several different articles where the WWVB phase shift is >>>>>> eliminated by doubling the signal to 120 kHz. Several members of the >>>>>> list have built these units. >>>>>> >>>>>> Assume I build a circuit to double the incoming signal and use a >>>> schmitt >>>>>> trigger to get a 120 kHz square wave. If I then divide that signal back >>>>>> down to 60 kHz will that signal be strong enough to swamp out the WWVB >>>>>> signal? I'm guessing it will be since it is at the 5 volt level and >>>>>> somewhere in the +25 dBm or greater range. >>>>>> >>>>>> Ray, >>>>>> AB7HE >>>>>> >>>>>> _______________________________________________ >>>>>> 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. >>>> >>> _______________________________________________ >>> 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. > > _______________________________________________ > 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.