(Geoffrey S. Mendelson) writes:

Frnak McKenney wrote:
Not sure what you could be referring to... other than the three
computers, 25" monitor, printer, Atmel AVR development board (8MHz
clock), flourescent desk lamp, and overhead I-look-like-an-
incandescent flourescent helix... all within 3 feet of the antenna
and clock. grin!

With all that hardware, wouldn't NTP (internet time) be a better option? Or if
you are not too deep into steel and concrete a GPS receiver?

Sounds like OP is really interested in bringing his father's WWV clock
to life.

But if correct time is the objective, ntp is easy. Over the internet
it is supposed to be accurate to tens of milliseconds. On our network,
1 - 5 ms is typical, but I suppose it is quite well behaved.

A GPS intended for timing gives better than 100 ms accuracy off the
cable. It can discipline ntp on a computer to typically 1 - 10 us
accuracy.

It looks like the Garmin GPS 18lvc us the timing GPS of choice for
hobbyists. You need a pulse per second (PPS) signal. There are other
GPS dongles which don't have PPS on the plug, but you can find the signal on
the circuit board.

More info at TAPR: "http://www.tapr.org". See also the timekeepers
mailing list archive:
"http://fortytwo.ch/mailman/pipermail/timekeepers/".

John Ackerman N8UR is an authority on timing and ham radio.

But again - this is probably not what you're really after :-)

73
LA4RT Jon

Jon Kåre Hellan wrote:
Sounds like OP is really interested in bringing his father's WWV clock
to life.
But again - this is probably not what you're really after :-)

A totaly different approach occured to me when I found that there
were no time signals readable here. WWV, CHU (if it is still around)
and their European equivalents never seem to be readable here.

The 60 kHz WWV coverage map puts me almost a 1000 miles beyond the edge
of their "weak but occasionaly useable" (my words) propigation. Someone
on another list claims his clock syncs about 30 miles north and at sea
level, but he never answered a question of too what and how often. :-(

What I thought of doing was sort of an radio to NTP interface. Access
the time information via NTP and then modulate a signal with it. 10 mHz
would be more difficult, you might be able to get 60kHz with a sound
card, or something like it. Obviously, you would not need or want
anything very strong and you may be able to couple it directly to the
antenna socket.

I know it would be cheating, but it seems like a fun hardware/software
project. You probably could get a magazine article published about it,
and maybe even sell enough boards to to offset the cost of making them.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

Jon Kåre Hellan wrote:
(Geoffrey S. Mendelson) writes:


Frnak McKenney wrote:

Not sure what you could be referring to... other than the three
computers, 25" monitor, printer, Atmel AVR development board (8MHz
clock), flourescent desk lamp, and overhead I-look-like-an-
incandescent flourescent helix... all within 3 feet of the antenna
and clock. grin!

With all that hardware, wouldn't NTP (internet time) be a better option? Or if
you are not too deep into steel and concrete a GPS receiver?


Sounds like OP is really interested in bringing his father's WWV clock
to life.

But if correct time is the objective, ntp is easy. Over the internet
it is supposed to be accurate to tens of milliseconds. On our network,
1 - 5 ms is typical, but I suppose it is quite well behaved.

A GPS intended for timing gives better than 100 ms accuracy off the
cable. It can discipline ntp on a computer to typically 1 - 10 us
accuracy.

It looks like the Garmin GPS 18lvc us the timing GPS of choice for
hobbyists. You need a pulse per second (PPS) signal. There are other
GPS dongles which don't have PPS on the plug, but you can find the signal on
the circuit board.

More info at TAPR: "http://www.tapr.org". See also the timekeepers
mailing list archive:
"http://fortytwo.ch/mailman/pipermail/timekeepers/".

John Ackerman N8UR is an authority on timing and ham radio.


Why not take the GPS disciplined oscillator (e.g. a Z8301) and use that
to synthesize a fake WWV signal (which you could program up in the AVR),
and radiate that to your MACII. You can easily divide down the 10 MHz
from the oscillator to generate all the needed modulations for WWV (the
tones, ticks, and 100 Hz timecode). Synthesizing the voice
announcements might be a bit more challenging grin "At the tone,
Coordinated Universal Time is...." You could even have a switch to
change back and forth between WWV and WWVH.



But again - this is probably not what you're really after :-)

73
LA4RT Jon

Jim Lux wrote:

Why not take the GPS disciplined oscillator (e.g. a Z8301) and use that
to synthesize a fake WWV signal (which you could program up in the AVR),
and radiate that to your MACII. You can easily divide down the 10 MHz
from the oscillator to generate all the needed modulations for WWV (the
tones, ticks, and 100 Hz timecode). Synthesizing the voice
announcements might be a bit more challenging grin "At the tone,
Coordinated Universal Time is...." You could even have a switch to
change back and forth between WWV and WWVH.

Talking clock programs have been around for a long time. All you need
is samples for 0 through 24, 30, 40, and 50 and a few words. You could
even play games with it, I'm sure the clock does not care, for
example "At the beep, the fake univeristy time is" and so on.

You really don't need to do much at all, since if I remember correctly,
it's an AM modulated signal, with no modulation also being no carrier.
Am modulation and on/off switching of a high power radio signal is
fairly complex, but at the microwatt level it should be easy.

It's fairly slow so even a reed relay connected to a GPIO line
would do. I'm sure there are all sorts of digitaly controlled
analog switch chips that will quickly and cleanly switch 10mHz.

As an aside, if I remember correctly, the 60kHz version is just
pulse code modulation of a carrier at a very slow baud rate,
so it would be really easy.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/