Hi Tom:
I've built it and it works great. See:
http://www.prc68.com/I/Loop.shtml#K5JHF
Next is to develop a better loop antenna based on the Russian Ferrite rods.
---and---
The subject of my prior post, add thermal mass and insulation to the
32768 crystal.
Have Fun,
Next
This not your father's WWVB clock. Many CW output features and even Westminster
"chimes" have been added. In fact we have 22 selectable parameters for those
who like pushing buttons. Since it is very difficult to maintain a 60Khz RF link to WWVB
during the day the Atomic Clock indicates when it was last synced to WWVB. This will
allow you to experiment with various VLF antennas to see which is best. Antenna
orientation is also important and you can experiment there. I've been using some larger
ferrite rods (off eBay) with great success. Also tried some Litz wire antennas. Great fun.
The best way to describe all of it's features is to walk through the setup
process.
Power:
The Atomic Clock draws 0.22 mA running current, and 1.08 mA beeping current. To
reduce power consumption the microcontroller hunts for the correct WWVB signal
during the first 10 minutes of every hour. Two AA batteries should last a long
time.
Construction:
A diagram is located on the schematic page. Components on the back are shown in
mirror image.
Mount a 2pin header on the CMMR-6P-60 for antenna attachment and
experimentation. Remember this is “H” field, locate the ferrite rod away from
metal and at right angles to Ft Collins CO, WWVB for best reception….mostly in
the late evening and very early morning hours.
Use:
Step forward through the Modes by pushing the Mode button. Backup by holding in
the Mode button until you hear the first half second tick. You can repeat this.
If you hold the Mode button in for two half second ticks you go back to the
“clock”. All data is immediately stored in flash memory at the time you change
it. Clean display (no prefix) means you are “set” to WWVB, otherwise U,S,E,L is
displayed for Unsynced (no sync detected), Second sync detected (it requires
two good sync pulses before updating the time data with WWVB), Error (noise),
or Loss of any signal. The microcontroller wll attempt to detect WWVB and sync
up during the first 10 minutes of the hour (drawing ~1mA) it will then revert
to 0.22mA for the remaining 50 minutes whether synced or not to conserve the
battery. You can use #22 (below) to determine antenna effectiveness.
Modes/Parameters: Initial default is Clock shown as “HH – MM – SS” with; Offset
= -6, Interval = 1min, Beeper On, Call On, Tick On, and Westminster On
Offset ….GMT offset selectable from -12 to 12
Beeper On/Off ….One mode provides all sound On/Off for quiet running (wife's
request)
Beeper Tone …. Frequency selectable from 294 Hz to 2093 Hz
Beeper Speed …. Morse WPM selectable from 3 WPM to 40 WPM
Beeper Interval …..Selectable output interval of #14 and/or #15 from 1 to 60
minutes. Test mode output including everything for “0” interval
Call 1 …. Callsign entry (saved) by number A-Z = 1 - 26, 1234567890 = 27-36
Call 2 ….same as #6
Call 3 ….same as #6
Call 4 ….same as #6
Call 5 ….same as #6
Call 6 ….same as #6
Call 7 ….same as #6
Call 8 ….same as #6
Call On/Off ….Send Morse Code call sign "de Callsign Callsign" up to 8
characters for output to Beeper, LED, and Key output for rig
Time On/Off …. Send Morse Code Time to Beeper, LED, and Key output for rig
Westminster On/Off …. Westminster Chimes on Quarter Hour with Hour(s) “Gong” on
the Hour
Tick On/Off ….One second tick
RS232 9600/4800 Baud ….9600 or 4800 Baud selectable for $GPZDA time data RS-232
output
Display 12Hr/24Hr …. 12Hr or 24Hr mode shown on the LCD
Set Hour …. Manual setting of Hours and Minutes if necessary
Set Minute …. Manual setting of Hours and Minutes if necessary
Tells you when the last successful setting to WWVB occurred, format:
"YYMMDDHHMMSS"
The price for the WWVB Atomic Clock Kit #7 (without the CMMR-6P-60) is $20 plus
$2 postage in the USA and $5 postage for DX. The CMMR-6P-60 is available for
$10 with no additional postage if ordered with the kit. We did that since
several local people already have this WWVB receiver and the other worldwide
time standards require different receivers and microcode (which is TBD).
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