Hi The standard 3’ loop was not anything really exotic. There are a lot of ham / SWL articles out there showing very similar designs.
One of many hits from Google: https://www.rfcafe.com/references/electronics-world/vlf-loop-antenna-january-1963-electronics-world.htm <https://www.rfcafe.com/references/electronics-world/vlf-loop-antenna-january-1963-electronics-world.htm> Bob > On Oct 9, 2020, at 8:04 PM, John C. Westmoreland, P.E. > <[email protected]> wrote: > > Paul, > > Thanks for that detailed explanation. I've done something similar for MARS > but of course higher frequency and that was transmit also. > > I've seen the site of something similar but I think that was a 3' diameter > design; and I've looked at some of the Symmetricom schematics I've > been able to find but have yet to find a schematic of one of > the Symmetricom receive antennas. I was hoping to find the one they had > for outdoor pole mount. It's mentioned in a lot of their documents and > even some pics but no schematic details or BOM for that I've been able to > find. > > Thanks to Tim also for the response and have a good weekend! > > 73's, > John > AJ6BC > > On Fri, Oct 9, 2020, 15:24 paul swed <[email protected]> wrote: > >> John I don't think so as not sure how many have built a large antenna. >> Certainly any of the old wwvb receivers have details and thats pretty much >> what most people copy. >> Essentially a 3 foot copper loop with numbers of turns of wire connected >> together. Like 25 pair telco cable connected end to end. A large capacitor >> is then put across the loop to resonate it at 60 KHz. Then the preamp. Some >> use a FET transistor followed by a line driver transistor. Power is sent >> over the coax so a blocking cap and inductor. >> Really big is 10' by 10' using shielded 36 wire ribbon cable. ( did not use >> all 36 conductors it was to much L but 800 ft worth. The shield acts like >> the copper pipe and it must be broken so that it does not look like a >> shorted loop. Add the cap and preamp. >> In this case I built a 2 transistor NPN 2n3904 preamp. >> On the large antenna I use a 2 X 6 post 4ft in the ground with cement. A >> mast above that to support the antenna and to allow it to be turned a bit >> to null MSF. >> Thats it no real magic. Its been operational for 7 years with an occasional >> transistor replacement. Also coax, darn woodpeckers! >> Regards >> Paul >> WB8TSL >> >> >> On Fri, Oct 9, 2020 at 5:14 PM John C. Westmoreland, P.E. < >> [email protected]> wrote: >> >>> Bob, >>> >>> Thanks for the answer; but does anyone actually have a documented >>> specification posted for one of these 'massive' WWVB 60kHz antennas >>> someplace? >>> >>> Thanks. >>> >>> 73's, >>> John >>> AJ6BC >>> >>> >>> On Fri, Oct 9, 2020, 08:35 Bob kb8tq <[email protected]> wrote: >>> >>>> 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. < >>>> [email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> >>>>>>> Date: Thu, October 08, 2020 12:40 pm >>>>>>> To: Discussion of precise time and frequency measurement >>>>>>> <[email protected]> >>>>>>> >>>>>>> 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, <[email protected]> < >>>>>>> [email protected]> 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 -- [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. >>>> >>>> >>>> _______________________________________________ >>>> 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.
