[time-nuts] WWVB Chronverter update progress
paulswedb at gmail.com
Mon Aug 27 18:05:19 EDT 2018
Well tinkering around and have 20 X 13 MHz vectron TCXOs.
I have to say impressive. Ran it from 73-100 degrees. Its starts 40 Hz low
and only moves 5 Hz over the range.
Just my luck no 12 MHz units. Though I do have a number of 9.6 Mhz vectron
and div 160 gets 60 KHz.
They are actually only VTOs and have no specs on them. But they do run at
5V with no smoke.
Will see as 160 is a number I can work with chip wise.
As I say the phase tracking clocks are tight so no wiggle room.
Did test the vectron VTO's. No markings from 73-100 degrees 6 hertz temp up
Will have to add a pot with a stable reference for the Vtune. But appears
good enough for what I need.
One day when bored I could add a tempsnsor and opamp to correct even that.
Now to dig up the divider chips and figure out how I want to mount the VTO.
On Mon, Aug 27, 2018 at 3:21 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
> One of the “interesting” things about the phase modulation on WWVB is that
> it does not get converted to
> AM (and thus mess things up) in the front end filters of the typical
> watches and clocks. The filters also do
> not strip off the AM modulation sidebands of the signal. One would *guess*
> that the filters have to be at least
> 20Hz wide (+/- 10 Hz relative to 60,000 Hz) to make this happen.
> > On Aug 27, 2018, at 2:26 PM, Larry McDavid <lmcdavid at lmceng.com> wrote:
> > Tim, there is indeed a consumer clock that uses only the BPSK modulation
> on WWVB. It is an "ULTRATOMIC" clock by La Crosse and has available on
> Amazon for over a year now. I have two of these clocks. They are *vastly*
> more sensitive than the usual "atomic" AM clocks. My actual experience is
> that these clocks will sync to WWVB within 10 minutes any time of day,
> completely unlike the usual AM "atomic" clocks.
> > Several years ago I had radiant barrier thermal insulation installed in
> my home attic; it forms essentially an aluminum umbrella over my home, an
> unexpected result. I had to relocate all my AM "atomic" clocks to (the
> inside of) outside walls for them to sync overnight. However, the
> ULTRATOMIC clocks will sync within 10 minutes any time of day, anywhere
> within my home.
> > But, so far as I can determine, this one rather large analog-display La
> Crosse clock is the only consumer BPSK clock available. It uses two or four
> C-cells for power and claims up to 6 years "battery" life. I installed two
> C-cells and they were only slightly depleted after one year. The clock can
> be configured for time zone and to inhibit motion of the second hand
> between midnight and 5 am. For me, one advantage is that the clock face is
> large enough that I can read it without my glasses!
> > Look here:
> > https://www.amazon.com/Crosse-Technology-404-1235UA-SS-
> > or search ULTRATOMIC La Crosse on Amazon.
> > Tom Van Baak did a tear-down has many pictures posted on his website;
> look here:
> > http://www.leapsecond.com/pages/ultratomic/
> > Larry
> > On 8/27/2018 8:12 AM, Tim Shoppa wrote:
> > ...
> >> Now, if this is a fancy-pants consumer WWVB wall clock that also expects
> >> the phase shift keying (not just amplitude keying) then I have no idea
> >> it'll respond to just plain amplitude keying for the time code. You
> >> think the WWVB BPSK chip will respond to loud and clear amplitude
> >> modulation but I have no experience with this. Nor do I even know if a
> >> single consumer clock was ever sold with BPSK ability.
> >> Tim N3QE...
> > --
> > Best wishes,
> > Larry McDavid W6FUB
> > Anaheim, California (SE of Los Angeles, near Disneyland)
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