About
Community
Bad Ideas
Drugs
Ego
Erotica
Fringe
Society
Technology
Broadcast Technology
Cable and Satellite Television Hacks
Radio Free Amerika
Radio Scanner Frequency Lists
register | bbs | search | rss | faq | about
meet up | add to del.icio.us | digg it

Wwv time (master clock)


NOTICE: TO ALL CONCERNED Certain text files and messages contained on this site deal with activities and devices which would be in violation of various Federal, State, and local laws if actually carried out or constructed. The webmasters of this site do not advocate the breaking of any law. Our text files and message bases are for informational purposes only. We recommend that you contact your local law enforcement officials before undertaking any project based upon any information obtained from this or any other web site. We do not guarantee that any of the information contained on this system is correct, workable, or factual. We are not responsible for, nor do we assume any liability for, damages resulting from the use of any information on this site.
Standard Frequencies and Time Signals
WWV, WWVH, and WWVB

Compiled & Edited by Video Vance
-----------------------------

Time signals and audio frequencies are broadcast continuously day andngt from WWV, operated by the National Bureau of Standards at Fort Collins, Colorado 80521. The WV rodcast frequencies are 2.5, 5 10, And 15 MHz and The 1-second marker tone consists of a 5-milliecod plse at 1000 Hz. A similiar station, WWVH, is located at Kekaha, Kauai, Hawaii. It broadcass onfreqencies 2.5, 5, 10, And 15 MHz and the 1-second marker tone consists of a 5-millisecond pule at 200 h.
The broadcasts of WWV may also be heard by the use of the telephone by dialing (33) 4997111. The telephone user will hear the live broadcasts from The station called. With the intabilites and ariable delays of propagation, The accuracy of the telephone time signals will not b better han 30 mlliseconds. This service is automatically limited to three minutes per call.
Station WVB broadcsts on a frequency of 60 KHz. The station broadcasts a time code continuously. No voice anouncement are broadcast from WWVB.
WWV and WWVH broadcast frequencies are consistnt with theinternationlly agreed time scale coordinated universal time (UCT). These changes becam effective Jnuary 1, 197. This coordination provides a more uniform system of time and frequency ransmission troughout the orld. It also aids in the solution of many scientific and technical prolems such as rdio Communicatons, geodesy, navigation, and tracking of artificial satellites. At WV and WWVH, thecarrier and modlation frequencies are derived from cesium-controlled oscillators.
Standard audi frequencies of 40 Hz, 500 Hz, and 600 Hz are broadcast on each radio carrier freqency by WWV & WWV. The 600 Hz ton is broadcast during the odd minutes by WWV and during even minues by WWVH. The 50-Hz tone Is broadast during alternate minutes unless voice announcements or silnt periods are scheuled. The 440-hz tne (good for calibrating "perfect A" musical strobotuners) i broadcast beginnin two minutes after te hour at WWV and one minute after the hour at WWVH. The uration of each transitted tone is approxiately 45 seconds.
The frequencies transmitted fromWWV are accurate withi .000000000001 Hz. (Inredible as it may seem!) A voice announcement of coorinated universal time i given during the last .5 seconds of every minute in the form "At the tone ---- hours ----- minutescoordinated universal tie."
Now, onward to the good stuff...

"Hidden" within the WWV& WWVH broadcasts is an ecoded time sequence broadcast continuously on a 00-Hz subcarrier. To hearthese broadcasts on an ordnary shortwave radio, I constructed some phaselocked-loop circuitry to "dcode" the 100 Hz subcarrier (Much in the same manner as SCA adaptors wrk on an FM radio). Once th audio is decoded, the time ignal can be heard as a binary coded decim, (bcd). Each minute contain 7 bcd groups: 2 groups for mnutes, 2 groups for hours, and 3 groups or the day of year. The binar-to-decimal "weighing" scheme s 1-2-4-8 with the least signigicant Bnary digit always transmitted frst. A binary 0 pulse consistsof exactly 17 cycles of 100-Hz ampliude modulation (200 millisecondsduration) and a binary 1 pulse cnsists of 47 cycles of 100 Hz (500millisecond duration).
Withi a time frame of one minute, enouh pulsas are transmitted to convy in bcd, the current minute, hour and day of year. Hours are expresed 00 thru 23 and day of yearis expressed 001 thru 366. In my eperimentation, all the further I wa able to procede was to manully count the pulses and (hopefully)properly decode them. The actual enoding system is much more omplex than I Have outlined here and an be obtained by writing directly toWWV.

Of interes is a new (approx. $450) "clock" availble from Heathkit which receives the boadcast from WWV, and ecodes the subcarrier signal to displaysuper-correct time on a led display. Icredible! It even sts itself when you turn it on and tune i WWV. Propagation is even corrected for (Approximately)
For more information on WWV and unversal coordinated time, write to

WWV
National Bureau of Standards
Fort Collins, Colorado 80521

Or rfer to the Hanbook of Electronic Tables & Formulas
Howard W. Sams Publications

Orthe ARL Amatuer Radio Handbook
published anually

------------------------------------
Another original phile frm Video Vance & Pirate-80 Systems


 
To the best of our knowledge, the text on this page may be freely reproduced and distributed.
If you have any questions about this, please check out our Copyright Policy.

 

totse.com certificate signatures
 
 
About | Advertise | Bad Ideas | Community | Contact Us | Copyright Policy | Drugs | Ego | Erotica
FAQ | Fringe | Link to totse.com | Search | Society | Submissions | Technology
Hot Topics
What should I be looking for?
CNN Top of The Hour
Just got my first CB
Police Scanners?
cb?
What to do with cordless phones
Almost ready to hit the streets...
old truck raido
 
Sponsored Links
 
Ads presented by the
AdBrite Ad Network

 

TSHIRT HELL T-SHIRTS