§ 200.107 15 CFR Subtitle B, Ch. II (1–1–13 Edition) papers in the journals and books of pro- § 200.107 WWV-WWVH-WWVB broad- fessional organizations, technological casts. associations, and commercial publica- (a) Technical services. The NIST radio tions. The calibration services, stand- stations WWV at Fort Collins, Colo- ard reference materials and related rado, and WWVH on the island of measurement services along with Kauai, Hawaii, broadcast a number of changes and fees are published in two technical services continuously night Special Publications (SP’s) and their and day. These services are: supplements. These are SP 250 ‘‘Cali- (1) Standard radio frequencies, 2.5, 5, bration and Related Measurement 10, 15, and 20, MHz (WWV) and 2.5, 5, 10, Services of the National Institute of and 15 MHz (WWVH); (2) standard time Standards & Technology’’ 1 and SP 260 signals; (3) time intervals; (4) UTI cor- ‘‘NIST Standard Reference Materials rections; (5) standard audio fre- Catalog.’’ 1 A complete catalog of all quencies; (6) standard musical pitch; (7) publications by NIST authors is issued a slow time code; (8) Omega Navigation annually as a supplement to SP 305 System status reports; (9) geophysical ‘‘Publications of the National Institute alerts; and (10) marine storm warnings. NIST also broadcasts time and fre- of Standards & Technology.’’ An- quency signals from its low frequency nouncements and listings of recent station, WWVB, also located at Fort NIST publications and services are Collins, Colorado. published in each issue of the bi- (2) [Reserved] 2 monthly ‘‘NIST Journal of Research’’ (b) Time announcements. Once per and the NIST monthly magazine, ‘‘Di- minute voice announcements are made mensions/NIST’’ 2. Complete citations from WWV and WWVH. The two sta- to NIST publications, along with infor- tions are distinguished by a female mation on availability are published voice from WWVH and a male voice bimonthly in the ‘‘NIST Publications from WWV. The WWVH announcement Newsletter’’, available free from the occurs first, at 15 seconds before the Technical Information and Publica- minute, while the WWV announcement tions Division, National Institute of occurs at 71⁄2 seconds before the Standards & Technology, Washington, minute. Coordinated Universal Time DC 20234. NIST publications are also (UTC) is used in these announcements. announced (with abstracts) in ‘‘Gov- (c) Time corrections. The UTC time ernment Reports Announcements and scale operates on atomic frequency, Index’’ published every two weeks by but by means of step adjustments is the National Technical Information made to approximate the astronomical Service (NTIS), Springfield, Virginia UTI scale. It may disagree from UTI by 22161 3. NTIS also sells microfiche cop- as much as 0.9 second before step ad- ies of all NIST GPO-published docu- justments of exactly 1 second are ments, as well as paper copy and made. These adjustments, or leap sec- microfiche versions of NIST Inter- onds are required about once per year agency Reports. and will usually be made on December 31 or June 30. For those who need as- tronomical time more accurately than 1 Single copies available free from the Na- 0.9 second, a correction to UTC is en- tional Institute of Standards & Technology, coded by the use of double ticks after Washington, DC 20234. 2 For sale by the Superintendent of Docu- the start of each minute. The first ments, U.S. Government Printing Office, through the eighth seconds ticks will Washington, DC 20402, for a subscription indicate a ‘‘plus’’ correction, and from price. The annual subscription price for the the ninth through the 16th a ‘‘minus’’ NIST Journal of Research on the date of the correction. The correction is deter- publication of these regulations is $13.00 and mined by counting the number of dou- for Dimensions/NIST it is $11.00. Prices, how- ble ticks. For example, if the first, sec- ever, for these publications are subject to ond, and third ticks are doubled, the change without notice. 3 The annual subscription rate at the date correction is ‘‘plus’’ 0.3 second. If the of the publication of these regulations for ninth, 10th, 11th, and 12th ticks are this service is $275.00, North American Con- doubled, the correction is ‘‘minus’’ 0.4 tinent, $375.00 all others. second. 356 VerDate Mar<15>2010 08:23 Feb 08, 2013 Jkt 229050 PO 00000 Frm 00366 Fmt 8010 Sfmt 8010 Y:\SGML\229050.XXX 229050 wreier-aviles on DSK5TPTVN1PROD with CFR NIST, Dept. of Commerce § 200.107 (d) Standard time intervals. An audio tions are in operation around the pulse (5 cycles of 1000 Hz on WWV and world. Omega, like other radio naviga- 6 cycles of 1200 Hz on WWVH), resem- tion systems, is subject to signal deg- bling the ticking of a clock, occurs radation caused by ionospheric disturb- each second of the minute except on ances at high latitudes. The Omega an- the 29th and 59th seconds. Each of nouncements on WWV and WWVH are these 5-millisecond second pulses occur given to provide users with immediate within a 40-millisecond period, wherein notification of such events and other all other modulation (voice or tone) is information on the status of the Omega removed from the carrier. These pulses system. begin 10 milliseconds after the modula- (i) Geophysical alerts. These occur in tion interruption. A long pulse (0.8 sec- voice at the 18th minute of each hour ond) marks the beginning of each from WWV. They point out outstanding minute. events which are in process, followed (e) Standard frequencies. All carrier by a summary of selected solar and and audio frequencies occur at their geophysical events in the past 24 hours nominal values according to the Inter- and a forecast for the next 24 hours. national System of Units (SI). For peri- They are provided by the Space Envi- ods of 45-second duration, either 500-Hz ronment Laboratory, National Oceanic or 600-Hz audio tones are broadcast in and Atmospheric Administration, alternate minutes during most of each Boulder, CO 80303. hour. A 440-Hz tone, the musical pitch (j) Marine storm information. Weather A above middle C, is broadcast once per information about major storms in the hour near the beginning of the hour. Atlantic and eastern North Pacific are (f) Accuracy and stability. The time broadcast in voice from WWV at 8, 9, and frequency broadcasts are con- and 10 minutes after each hour. Similar trolled by the NIST atomic frequency storm warnings covering the eastern standards, which realize the inter- and central North Pacific are given nationally defined cesium resonance from WWVH at 48, 49, and 50 minutes frequency with an accuracy of 1 part in after each hour. An additional segment 10 13. The frequencies transmitted by (at 11 minutes after the hour on WWV WWV and WWVH are held stable to and at 51 minutes on WWVH) may be better than ±2 parts in 10 11 at all times. used when there are unusually wide- Deviations at WWV are normally less spread storm conditions. The brief mes- than 1 part in 10 12 from day to day. In- sages are designed to tell mariners of cremental frequency adjustments not storm threats in their areas. If there exceeding 1 part in 10 12 are made at are no warnings in the designated WWV and WWVH as necessary. areas, the broadcasts will so indicate. Changes in the propagation medium The ocean areas involved are those for (causing Doppler effect, diurnal shifts, which the U.S. has warning responsi- etc.) result in fluctuations in the car- bility under international agreement. rier frequencies as received which may The regular times of issue by the Na- be very much greater than the uncer- tional Weather Service are 0500, 1100, tainties described above. 1700, and 2300 UTC for WWV and 0000, (g) Slow time code. A modified IRIG H 0600, 1200, and 1800 UTC for WWVH. time code occurs continuously on a 100- These broadcasts are updated effective Hz subcarrier. The format is 1 pulse per with the next scheduled announcement second with a 1-minute time frame. It following the time of issue. gives day of the year, hours, and min- (k) ‘‘Silent’’ periods. These are periods utes in binary coded decimal form. with no tone modulation during which (h) Omega announcements. Omega the carrier, seconds ticks, minute time Navigation System status reports are announcements, and 100 Hz modified broadcast in voice from WWV at 16 IRIG H time code continue. They occur minutes after the hour and from during the 16th through the 20th WWVH at 47 minutes after the hour. minute on WWVH and the 46th through The international Omega Navigation the 51st minute on WWV. System is a very low frequency (VLF) (l) WWVB. This station (antenna co- radio navigation aid operating in the 10 ordinates 40°40′28.3″ N., 105°02′39.5″ W.; to 14 kHz frequency band. Eight sta- radiated power 12 kw.) broadcasts on 60 357 VerDate Mar<15>2010 08:23 Feb 08, 2013 Jkt 229050 PO 00000 Frm 00367 Fmt 8010 Sfmt 8010 Y:\SGML\229050.XXX 229050 wreier-aviles on DSK5TPTVN1PROD with CFR § 200.108 15 CFR Subtitle B, Ch. II (1–1–13 Edition) kHz. Its time scale is the same as for strictions on the use of results as set WWV and WWVH, and its frequency ac- forth in § 200.113 of this part. Accept- curacy and stability are the same. Its ance of purchase orders does not imply entire format consists of a 1 pulse per acceptance of any provisions set forth second special binary time code giving in the order contrary to the policy, minutes, hours, days, and the correc- practice, or regulations of NIST or the tion between its UTC time scale and U.S.