[time-nuts] The WWVB Atomic Clock Kit #7

Tom Clifton kc0vsj at yahoo.com
Mon Feb 1 15:25:35 EST 2010

I noted this while looking for a DDS VFO, and thought it interesting and affordable if you are interested in a 60khz WWVB receiver kit  for $30 plus postage.  As a standard disclaimer, I have no affiliation with the gents producing  the kit.  The URL is:  http://www.qsl.net/k5bcq/Kits/Kits.html

And verbage from the site is as follows:

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. 

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. 

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. 

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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