[time-nuts] Re: Loop Antennas

[paul swed]

Hello to the group.
If the solution is for LORAN C then a wider band antenna is needed. Exactly
as Poul states.
Then for narrow band signals such as wwvb narrow band.
My solution is as follows.
WWVB 10' X 10' square loop resonant at 60 KHz about 1Khz wide or so. It has
worked well for 10 years. Then a preamp.
eLORAN 4' X 4' square loop resonant at 100 KHz and broad banded to tp +/-
15 KHz. Preamp at the antenna.
Square loops are easy to build with plumbing parts. The eLORAN antenna can
be turned 180 degrees. Because currently the tests can come from any
direction. Though right this second they are west of me by 1800 miles.
I also have available simply by changing a connection a classical LORAN C
whip antenna.
I did build the eLORAN antenna just for the fun of it.

Reality is it depends on how far away you are and many other antennas can
work. Simple wire, whips and preamps etc.

Regards
Paul
WB8TSL

On Wed, Jun 7, 2023 at 9:29 PM Alex Pummer via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hi Bob,
> that is my 60kHz remote receiver,
> the remote tuning could be made relative simple, see the attached
> circuit diagram; by changing the supply voltage -- right to corner --
> between 15V and 20V the tuning voltage for the varicaps  -- D8 and D9 --
> will change between +1V and +10,5V, which causes 800pF capacitance
> changing the coil  L6 is approx 2,2mHy,
> D6 an D7 prevent the damage Q25 gate, the op-amp circuit is matching the
> high impedance of the C108 L7 tank circuit to 50 ohm cable impedance. At
> the 20 long end of the cable -- with 50 termination -- I could see a p_p
> voltage  between 60mV and 500mV here in the Bay Area, in California,
> behind the wall, inside of the house, outside I could get at least 6dB
> more.
> I am using that antenna for a frequency reference  --  a 10MHz PLL is
> locked to that 60kHz -- only just to verify that the output of the GPS
> is locked correct
>
> 73
> KJ6UHN
> Alex
>
>
> On 6/7/2023 2:47 PM, Bob Camp via time-nuts wrote:
> > Hi
> >
> > The next layer to this is that some (but not all) WWVB receiver designs
> appear to rely
> > upon the “bandpass filter” of the antenna to provide reasonable
> rejection of “crud”.
> >
> > Having any sort of resonant circuit out in the back yard has
> implications. As the resonance
> > shifts with temperature, so does the phase shift. At VLF phase is indeed
> a big deal. Just
> > how big a deal …..
> >
> > As with a lot of things, you can indeed measure outside temperature and
> model this or that.
> > Lots of fun can be had.
> >
> > Bob
> >
> >> On Jun 7, 2023, at 5:30 PM, Graham / KE9H <ke9h.graham at gmail.com>
> wrote:
> >>
> >> For WWVB time signals, I use a resonant ferrite rod antenna, but
> depending on the rod, the antenna bandwidth can be several hundred to
> several thousand Hz. Resonant multi-turn loops are likely to be similar.
> >>
> >> You will need a broad-band (non-resonant) loop for receiving Loran-C,
> due to the much wider modulation bandwidth of the signal.
> >> --- Graham
> >>
> >> On Wed, Jun 7, 2023 at 3:46 PM Bob Camp via time-nuts <
> time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
> >>> Hi
> >>>
> >>> There are a number of sites around the web that go through the details
> >>> of doing large-ish loop antennas for various LF signals. Are you
> trying to
> >>> do something small (fit in your pocket) or something fairly large (10
> foot
> >>> diameter) ?
> >>>
> >>> Bob
> >>>
> >>>> On Jun 7, 2023, at 2:25 PM, JOHN HARTZELL via time-nuts <
> time-nuts at lists.febo.com <mailto:time-nuts at lists.febo.com>> wrote:
> >>>>
> >>>> Dear time nuts,
> >>>>
> >>>> Who has experience using loop antennas on the front end of receivers
> for receipt of Loran C, and other time signals?
> >>>>
> >>>> Kind regards,
> >>>>
> >>>> John
> >>>>
> >>>> https://linkedin.com/in/john-h-6a131b12/
> >>>>
> >>>>
> >>>>
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