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.
