Does the La Crosse UltrAtomic clock actually use a crystal filter or do
they digitally filter the signal? Has anyone ever looked inside of one
of the clocks? Just curious.
Ray
AB7HE
Original Message
Subject: Re: [time-nuts] WWVB SDR discussion
From: Mark Haun
Date: Mon, August
Ray,
I don't see a crystal filter. There is a 16 MHz crystal, but that's for
the processor.
"Inside the La Crosse 1235UA UltrAtomic Radio Controlled WWVB (Atomic)
Wall Clock"
http://leapsecond.com/pages/ultratomic/
"ES100 datasheet, including block diagram, application circuit, and theory"
Hi,
you do not necessarily need a variable ( physical ) oscillator. You mix
the signal down in the digital domain. A 'digital local oscilator' is a
mere complex value, which is rotated and the power is adjusted:
#define CMUL(_a,_b,_c) \
{ _c.re = _a.re*_b.re-_a.im*_b.im; \
_c.im = _a
Hi Detlef,
On 11-Aug-20 3:46 AM, Detlef Schuecker via time-nuts wrote:
> you do not necessarily need a variable ( physical ) oscillator. You mix
> the signal down in the digital domain. A 'digital local oscilator' is a
> mere complex value, which is rotated and the power is adjusted:
My proposed
Hi everyone,
On 8/6/20 5:55 AM, jimlux wrote:
On 8/5/20 4:18 PM, Mark Haun wrote:
I wonder if someone maintains a directory of ionosondes. Seems like
waste/duplication to have every interested party set up their own,
instead of piggy-backing on what's already out there. There's also the
pollu
Should add that on the East Coast the signal is about 10 uv. On the large
10' X 10' loop I get about 63 uv during the day. That loop at night can
easily hit 1000 uv.
Regards
Paul
On Tue, Aug 11, 2020 at 3:37 PM paul swed wrote:
> Mark
> His antenna hit a preamp as I recall about 20 db of gain. T
Mark
His antenna hit a preamp as I recall about 20 db of gain. To see something
on a scope add 40 more db approx. Unfortunately a purely broadband solution
will show 40 db of pure garbage these days. Using the 60 KHz watch crystals
$2.00 for 20 out of China you can most likely find a reasonable mat
Hi
The problem with the crystal is that it has a temperature coefficient. As a
narrow band filter, it will have a *lot* of delay. Crystal resonance moves
(with temperature) and the delay changes.
How much delay depends a lot on a bunch of fiddly details. A 10 to 100 Hz wide
bandpass could easi
On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq wrote:
> The problem with the crystal is that it has a temperature coefficient. As a
> narrow band filter, it will have a *lot* of delay. Crystal resonance moves
> (with temperature) and the delay changes.
I agree. The crystal needs to be
I'm seeing more than 100mV p-p right now (7:09 PM) (2309 UTC) on the output of
my preamp from the east coast of New Jersey, 1622 miles east of WWVB.
During my early days of WWVB experimenting, I found the signal is easier to
spot (since it's buried in noise) if the scope's horizontal sweep is e
How do the small AM WWVB clocks work then. They use the 60 KHz crystal and
they don't actually do anything special. In measuring those clocks they are
about 2-6 hz wide. On the spectracoms the crystal is huge. Looks like a HC6
but 3" long. About 1-2 Hz wide.
Using the same small crystals in BPF fil
On Tue, Aug 11, 2020 at 10:27:33PM -0400, paul swed wrote:
> Just saying they work for all those atomic clocks for $10.
Those don't give a damn about 60 KHz delay/phase provided it
doesn't change very fast (as it wouldn't due to thermal effects).
But monitoring frequency or drift
> deriving exact time to way closer than a second from the signal
To the average consumer if the clock is accurate to within a minute or
so they are happy. The clocks also run on a RTC and only use WWVB to
keep the RTC more or less accurate. The clocks are also only looking at
the carrier level c
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