The additional article John sent us is a pretty good read. Having soldered all the little wires together with heat shrink, I can see the advantage of the epoxy approach.
A consideration for the discussion. So far its been about the various tried and true methods for a RF frontend. But the real challenge that is in front of us is the software that uses that frontend. How about a very easy to build a phase flipper so that those that are software inclined do not need to deal with the frontend to get going. The dpskr has a phase flipper in it. But it can be even simpler than that. A 60 KHz logic signal ( divide 6 Mhz down or anything else thats easy) Feeds an inverter to generate the 180 degree phase. A gate to select 0 or 180 degrees. All of the gates/inverters can actually be a single quad nand gate. A D flip flop with the clock from the 0 degree 60 KHz logic level. Your data into the D input. The D flip flop synchronizes the data to the clock. On the output you can filter the signal or not and cut the level down or not. Its a BPSK source. Granted in a pure gate approach the actual bpsk flip will not be the 2 X 60 KHz for 1/2 cycle. But in real receivers the 120 KHz never comes through the various stages and filters. So no real harm. This also doesn't supply the AM signals 14-17 db modulation. But its good enough to allow software to be developed and its simple. Good luck Paul WB8TSL On Sat, Oct 10, 2020 at 2:05 PM John Magliacane via time-nuts < time-nuts@lists.febo.com> wrote: > For WWVB reception, I use a single turn of 40-conductor ribbon cable, > configured as a 40-turn loop, brought to resonance with a parallel > capacitance, that differentially drives an instrumentation amplifier. No > electrostatic shielding is needed to eliminate e-field pickup with this > approach. > > The antenna hangs in my attic with thumbtacks and does a commendable job, > day or night, 1622 miles east of WWVB. See attached JPEG image. > > The March 2017 issue of "Circuit Cellar" magazine described an "improved" > version of my antenna/preamp combination (which I haven't looked into). > See attached PDF document. > > During my early experimentation, I realized that the preamp would need to > have a high dynamic range in order to perform well in the high-noise > environment that is LF. And if the preamp is going to feed a receiver > through any reasonable length of coax, it will need to be able to drive a > high capacitance load as well. > > > 73.000 de John, KD2BD > _______________________________________________ > 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.