VISIT TO NATIONAL BUREAU OF STANDARDS, HIGH-FREQUENCY STANDARDS DIVISION; REPORT ON

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03153A002000060002-4
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 32
• Document Creation Date: December 23, 2016
• Document Release Date: January 29, 2014
• Sequence Number: 2
• Publication Date: June 17, 1952
• Content Type: MEMO

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STERILIZED WORKING LEVEL MEMO
17 June 1952
From: Mac
To: Paul and Dave
Subj: Visit to National Bureau of Standards, High-Frequency
Standards Division; report on
End: (1) USNBS, Standard Frequencies and Time Signals,
WV and WWVH, dtd Apr 15, 1952
(2) USNBS, Standard Frequency Broadcast Reception,
preprint 51-28, dtd May 2, 1951
1. Visited NBS, 16 June 1952, and contacted Mr. E. L. Hall
(Telephone OR-4040 Ext. 217) in Radio Building No. 214.
2. Enclosures (1) and (2) cover the majority of questions you
had in mind.
3. Of particular interest to you is the information on trans-
mission from MSF, Rugby, England, which is covered on page 14
of enclosure (2). The report also includes a survey of world
reception from WV and WWVH.
4. Mr. Hall states England is considering to broadcast on a
round-the-clock basis and his superior, Mr. W. D. George, is on
an international committee regulating sudh matters. I will
follow up on the development of this problem and will report to
you any significant proposals or recommendations.
5. Mr. Hall also stated that Japan is coming into the broad-
casting picture. In addition, the reception in the Korean area
is very poor owing to interference from military broadcasting
when the assigned frequencies are not rigidly maintained.
6. The NBS had on file a proposal from:
Specific Products
5864 Hollywood Blvd.
Hollywood 28, Calif.
on tentative specifications for a specially designed receiver,
Model WWVR, to receive just time ticks on 5, 10, and 15 megacyles.
The cost is approximately $400.00 and the panel, I would estimate
from the drawing, is 5" x 10". This does not meet our require-
ments of cost and size but may be a source for our custom built
specifications. Won't follow up on this unless I hear from you.
POCIIMelit
Review of this dot:moat by CIA has
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Sincerely,
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U. S. DEPARTMENT OF COMMERCE
15, 1952 NATIONAL BUREAU OF STANDARDS Letter Circular
_WASHINGTON 25, D. C. LC1009
we STANDARD FREQUENCIES AND TIME SIGNALS (Supersedes
WWV AND WWVH LC974)
LL Radio Station WWV (in operation since 1923) and WWVH (since 1949) now broadcast con-
tinuously, night and day, giving six widely used services: STANDARD RADIO FREQUENCIES,
LIN
STANDARD TIME INTERVALS, TIME ANNOUNCEMENTS, STANDARD MUSICAL PITCH, STANDARD AUDIO FRE-
QUENCIES, AND RADIO PROPAGATION NOTICES.
gm
Awl. Radio Frequencies and Station Locations
am Station WWV (N 38? 591 33" W 76? 501 5211; near Washington, D. C.) broadcasts con_
JIB
1111
tinuously, night and day, on standard radio frequencies of 2.5, 5, 10, 15, 20, and 25 Mc.
Station li4WVH (N 20? 461 02", W 156? 271 42"; Maui, Territory of Hawaii) broadcasts on
standard radio frequencies of 5, 10 and 15 Mc. The WWW broadcast is interrupted for 4
...minutes following each hour and half hour and for periods of 34 minutes each day beginning
? at 1900 UT (Universal Time). Also, during the week including the third Tuesday of each
NMI
month, the WWW broadcast is interrupted from 1900 to 2200 UT as follows: 5 Mc on Tues-
day; 10 Mc on Wednesday; 15 Mc on Thursday.
2. Time Signals and Standard Time Intervals
The audio frequencies are interrupted for intervals of precisely one minute. They
Imare resumed precisely on the hour and each five minutes thereafter. They are in agree-
ment with the basic time service of the U. S. Naval Observatory so that they mark
accurately the hour and the successive 5-minute periods.
L.
Universal Time (Greenwich Civil Time or Greenwich Mean Time) is announced in tele-
10?
Li.graphic code each five minutes starting with 0000 (midnight). Time announcements are
pm given just prior to and are with reference to return of the audio frequencies.
L.
A voice announcement of Eastern Standard Time is given each five minutes from
station WWV; this precedes and follows each telegraphic code announcement.
A pulse on each carrier frequency of 0.005-second duration occurs at intervals of
Pm
precisely one second. The pulse consists of five cycles, each of 0.001-second
go duration.
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NATIONAL BUREAU OF STANDARDS
STANDARD FREQUENCIES AND TIME SIGNALS, WWV AND WWVH
WWV
BROADCAST CONTINUOUSLY
MC
POWER, KW
MODULATIONS, C/S
2.5
0.7
1,440 OR 600
5
8.0
1,440 OR 600
10
9.0
1,440 OR 600
15
9.0
1,440 OR 600
20
8.5 a
I, 440 OR 600
25
0.1
1,440 OR 600
30 b
0.1
1
35b
0.1
I
WWV I 600
START
EACH
HOUR
?I 440
5
WWVH I SILENT 440
WWV
600
WWVH c
BROADCAST CONTINUOUSLY
MC
POWER, KW
MODULATIONS, C/S
5
2.0
I;440 OR 600
1;440 OR 600
10
2.0
15
2.0
I; 440 OR 600
(o) 2.0 KW, FOR FIRST 4 WORK DAYS AFTER FIRST SUNDAY OF EVEN MONTHS.
(b) TO BE DISCONTINUED JANUARY 1,1953.
(c) REGULAR INTERRUTIONS EXPLAINED ON PAGE 1
NOTE: AMPLITUDE MODULATION, WWV AND WWVH PULSE, 100%, TONE, .
MODULATION FREQUENCIES
440
10 15 120 25 30 35 40 45 I 50
RADIO PROPAGATION DISTURBANCE WARNING NOTICE, W WV ONLY
* * * * *
600?I 440 600
WWVH SILENT 34 MINUTES BEGINNING AT 1900 UT
ISTART ONE MINUTE
ANNOUNCEMENT
INTERVALS
WWVH I
*ANNOUNCEMENT INTERVALS
CODE
600
440
600
440
^
55 END 160
EACH MIN
HOUR*
440
CODE VOICE CODE VOICE I
PROPAGATION NOTICE"CALL LETTERS AND EST UT EST I
END ONE MINUTE
ANNOUNCEMENT
INTERVALS
In a
a
0
RELATIVE VOLTAGE OR POWER
1.0
.9
.8
.7
.6
.5
.4
.2
UT AND CALL LETTERS_ 30
** 19-1- AND 49- MINUTES PAST EACH HOUR
It
I - 11- --, M - 8 -
ixt MI - 111t
II IN
14r-- i 7
INIW,,m111
l-c-- 0.005 SECOND
Ws,
ats?
al
I 1
rat?a
op....nr
I -4--
i
imr-vom
-1
0 200
.05
? '
1
W., will W
-r
HE - ? ? NCY STELTRUM Or ME
,SECONDS PULSES 4
?RELATIVE VOLTAGE ---- RELATIVE POWER
a
THE SPECTRUM IS COMPOSED OF DISCRETE
FREQUENCY COMPONENTS AT INTERVALS OF 1.0
c / s THE COMPONENTS NEAR 995 c /s ( the
spectral maximum) HAVE AMPLITUDES OF 0.005
VOLT FOR A PULSE AMPLITUDE OF 1.0 VOLT.
EACH PULSE CONSISTS OF FIVE CYCLES OF
1000 c / s , AND IS REPEATED ONCE EACH SECOND.
MIN
11111111111111111=111
III=A MEM III
1.1111._I ...?
11111= iihM ? AI
411
Ism
400 600 800 1000 1200
111
1400 1600 1800 2000 2200
FREQUENCY - (c / s )
2400 2600
2800 3000
WWV TIME SIGNALS, JANUARY, 19 48, THROUGH OCTOBER, 1951
TI I I II I I IIII I I I I 1-1- II I I
.05
DEVIATIONS FROM U.S. NAVAL OBSERVATORY TIME
DEV ATIONS FROM GREENWICH ENGLAND) OBSERVATORY TIME
( CORRECTED FOR PROPAGATION TIME, UNCORRECTED FOR POLAR VARIAT ON )
JFMAMJJASON DJFMAMJJ A SONDJF MAMJ JA
1948 1949 19 50
SONDJ FMAMJ J A SO
19 51
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.05
.04
03
.02
01
0I
02
03
04
05
a
60
SEC.
?
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3. Audio Frequencies and Musical Pitch
Two standard audio frequencies, 440 and boo cycles per second, are broadcast on
all radio carrier frequencies. The audio frequencies are given alternately, start-
ing with 600 cycles on the hour for four minutes, interrupted one minute, followed by
440 cycles for four minutes, and interrupted one minute. Each ten-minute period is
the same. The 440?cycle tone is the standard musical pitch A above middle C.
4. Accuracy
Frequencies transmitted from WWI/ and WWVH are accurate to within 2 parts in 108;
this is with reference to the mean solar second, 100-day interval, as determined by the
U. S. Naval Observatory with a precision of better than 3 parts in 109. Time intervals,
as transmitted, are accurate within + 12 parts in 108 + 1 microsecond'.
Frequencies received may be as accurate as those transmitted for several hours per
day during total light or total darkness over the transmission path at locations in the
service range. During the course of the day errors in the received frequencies may
vary approximately between -3 to +3 parts in 107. During ionospheric storms transient
conditions in the propagating medium may cause momentary changes as large as 1 part in 106?
Time intervals, as received, are normally accurate within + 12 parts in 108 + 1
millisecond'. Transient conditions in the ionosphere at times cause received pulses to
scatter by several milliseconds.
Corrections for the slight errors in absolute time and frequency as broadcast are
available quarterly to organizations having need for corrections.
5. Radio Propagation Disturbance Warning Notice fuDiggy
An announcement of North Atlantic radio propagation conditions is broadcast in code
on each of the standard radio frequencies at 19 1/2 and 49 1/2 minutes past the hour. If
a warning of disturbance is in effect, the letter Nn (in International Morse Code) is
repeated 10 times (keying tone 800 c/s) prior to the time announcement; if unstable
conditions are expected, the letter "U" is repeated 10 times (keying tone 1200 c/s); if
there is no warning, the letter "N" is repeated 10 times (keying tone 600 c/s). These
announcements are pertinent only to transmission paths in the North Atlantic area.
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OM,
VOW
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n
CRPL PREPRINT 51-28
C71
ISSUED MAY 2, 1951
U.S. DEPARTMENT OF COMMERCE
NATIONAL BUREAU OF STANDARDS
CENTRAL RADIO PROPAGATION LABORATORY
WASHINGTON, D.C.
STANDARD FREQUENCY BROADCAST RECEPTION
By
EL.Hall
THIS REPORT IS A PREPRINT OF MATERIAL WHICH HAS BEEN
SUBMITTED FOR REGULAR PUBLICATION AND IS ISSUED FOR INFORMATION
PURPOSES ONLY. PUBLICATION OR REPRINTING OF THE CONTENTS EITHER
IN FULL OR IN PART IS NOT AUTHORIZED WITHOUT EXPRESS PERMISSION.
THIS REPORT IS NOT AVAILABLE FOR FURTHER DISTRIBUTION.
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STANDARD FREQUENCY BROADCAST RECEPTION
By L. Hall
National Bureau of Standards
Washington 25, D. C.
ABSTRACT
This paper gives the results of a compilation of many thousands of
observations during 1950 on reception of standard frequency trans-
missions from the National Bureau of Standards experimental station
WWVH, Maui, T.H., and the more powerful station WWV, Beltsville, Mary-
land? Observations were made by several government agencies and by
individuals at numerous points in the United States, Alaska, the
Pacific area, Australia, and Jamaica. The data presented in tabular
and chart form extend much of the information presented in a previous
report to other seasons of the year.
A limited amount of information is given on the 5-Mc broadcasts
from JJY, Tokyo, and 5- and 10-Mc broadcasts from MBF,- Rugby, England.
The reports submitted indicate an increase in the standard fre-
quency coverage by operation of station WWVH, and no marked difficulty
from the operation of WWVH and WWV on the same frequencies. Data on
the operation of JJY and MSF have been too meager to draw any defi-
nite conclusions other than that no undesired effects were produced
in the United States.
CONTENTS
I. Introduction
Data on Reception of Standard Frequency Stations WWV and WWVH.
CAA Data.
-2-.-FCC Data.
3. Adak, Alaska, Data.
4. Anchorage, Alaska, Data.
5. Data from Los Angeles, California.
6. Data from South Australia.
7. Data from Kingston, Jamaica.
III. Reception of Other Standard Frequency Stations
1. Observations of 5-Mc Transmissions from JJY, Tokyo,
and WWVH, Maui, T.H.
2, Standard Frequency Transmissions from NSF, Rugby, England.
-IV. Discussion.
V. Conclusion
VI. Acknowledgment.
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I. Introduction
The present paper presents some of the results of reception of
standard frequency broadcasts, as reported to the National Bureau
of Standards, with a brief record of the establishment of such serviceil
and certain conclusions concerning world-wide coverage of standard fre-
quency and time services.
1. In,1923 the Bureau of Standards began transmissions of standard
frequencies from WWV.2-1 These transmissions consisted of several
groups of frequencies, each of which was available for a few minutes
in the evening once a month. The transmissions were announced in ad-
vance in the press, in radio periodicals, and in the Radio Service
Bulletin, a former publication of the Department of Commerce. Later
the service was gradually expanded until it has become available con-
tinuously 24 hours per day on eight frequencies.. / Many government
agencies and other organizations and individuals have cooperated with
the Bureau in making these services of maximum utility by sending
reception reports from which the coverage of the various frequencies
was determined. These reports indicated that adequate coverage was
not obtained some of the time in certain areas during some seasons.
The ideal of standard frequencies available all of the time at all
places was not realized.2/
2. This led to the establishment of a second standard frequency
station on an experimental basis on the island of Maui, T.H., in
November 1948. This station, WWVH, operates on three of the fre-
quencies of WWV, i.e., 5, 10, and 15 Mc, with a power of 400 watts.
Station WWVH is maintained on the correct frequencies with reference
to WV by means of special pie zq oscillators of high stability and
special monitoring techniques,t/
One of the questions to be answered VAS whether interference
would be experienced by users of these stations because of simul-
taneous operation. Another question related to how much the stand-
ard frequency coverage was extended by the second station.
The answers to these questions were again provided by a COTDS
of observers in various Government agencies and by individual observers.
1/ Standard frequenoy dissemination, M. S. Strock, Proc.TRE 15, 727 1927).
2/ Letter Circular LC974, Jan. 12, 1950, CRPL, National Bureau of Standards.
3/ Radio dissemination of the national standard of frequency, J.H.Dellinger
and E.L.Hall, Radio Engineering, 12, No. 5, 23 (1932).
4/ Frequency and time determinations at standard frequency broadcast
station WWVH, V. E. Heaton, Tele-Tech 10, 36, March 1951.
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3. Station JJY, Tokyo, Japan, gives standard frequency broadcasts on
4 and 8 Mc. Late in 1949 experimental standard frequency broadcasts were
given on 5 Mc for three weeks and were intended to give practical data on
5-Mc reception in Japan and other far eastern areas not covered well by
WWV or WWVH.
Reception of WWV is not always satisfactory in England and Europe.
The National Physical Laboratory on February 1, 1950, began an experi-
mental standard frequency transmission for a half-hour each day on each
of the frequencies 5 and 10 Mc from Rugby, England../ The station
call letters are MSF. Reports of reception of this station were received
from a number of localities in this country and a few other points.
II. Data on Reception of WWV and WWVH
-1 1. CAA Data
s_.
1
The Civil Aeronautics Administration submitted over 13,000 observa-
tions on reception of stations WWVH and WWV from September, 1949, through
July, 1950. The reports came from three main regions which may be de-
fined as the west coast, Alaska, and islands of the Pacific Ocean.
These are regions most likely to be benefited by transmissions from
station WWVH. The west coast included areas in California and Wash-
ington. Points in Alaska included Anchorage, Annette Island, Fairbanks,
and Nome. The Pacific islands were Canton, Guam, Midway and Wake. The
results are summarized in Table I, where "Better," Norse," and "Same"
refer to the reception of standard frequency and time signals as changed
by the addition of station WWVH. "Better" means either a stronger sig-
nal, or extension of the number of hours per day that standard fre-
quencies are available. "Sane" indicates no marked change in signal
intensities or increase in the hours of availability of the signals
beyond that noted for WWV. To be truly "Same" the tests should have
been made throughout the twenty-four hours. Very little of the data
met this requirement, but was interpreted on the basis of conditions
at the times of observation.
The intended meaning of Norse" was that standard frequency recep-
tion was actually worse at the location because of WWVH interfering
with WWV and making accurate frequency or time measurements more dif-
ficult. One and one-half percent of observations were marked "Worse",
but it is believed that many of these were erroneous. Correspondence
indicated that some of such markings were intended to indicate that
WWV was of greater intensity. Some of these data sheets were for-
warded to the observers, were corrected and returned.
The data in Table I indicate 20% better reception for the west
coast, 67% better for the Alaskan area, and about 88% better for the
Pacific area.
51J.K,Standard Frequencies, Wireless World 5 99, March 1950.
6Y Standard Frequency Transmissions, A. Graham Thomson, Wireless
World, 56, 137, April 1950.
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2. FCC Data
Observers in the field offices of the Federal Communications Com-
mission were well trained and equipped for accurate measurements. They
submitted several thousand observations on the WWV-WWVH transmissions.
These reports were divided into two groups for the United States, those
east of the Rocky Mountains comprising ten localities, and those west
of the Rocky Mountains, of which there were seven localities. Six of
the latter were along the seaboard. Observations were also made at
Fort Hase, Oahu, T.H.
The results are summarized in Table II where "Better", Norse,"
and "Same" have the same meanings as given above for data from CAA.
Reception east of the Rocky Mountains would not be expected to be im-
proved by a 400-watt station in Hawaii, hence 97% "Sane" seems reason-
able. The region west of the Rocky Mountains Showed a 30% improvement.
It is rather surprising to find only about 55% improvement at Fort Hase
so near to WWVH. The reason appears to be that WWV 's 15-Mc trans-
mission is of equal or greater intensity than WWVH's and hence given
a large number for "Same."
3. AIIISL.A1Mic1/21I1_
Monthly reports of reception of WWVH and WWV were received from
the U.S. Army's Ionospheric Station at Adak, Alaska, beginning in
November, 1949. These reports usually gave signal intensity readings
for each hour of each day of the month for 5, 10 and 15 Mc from WWVH
and 20 Mc from WWV. The signal intensity was given on a 0-9 basis
each hour, from which the average intensity for the month was com-
puted. A low monthly average value does not necessarily mean that
the received intensity was consistently low for the particular hour
or times considered; rather it may have been zero for many days and
high for a few days. The original data show this, but the fact is
obscured by taking an average which, however, appears to be the most
practical way of presenting the data.
Reception of radio station WWVH on 5 Mc at Adak is shown for
twelve months in Fig. 12 where signal intensity is plotted for each
hour. The lower portion of Fig. 1 shows the times of sunrise and
sunset at station WWVH and Adak for the twelve months of the year.
It will be noted that the 5-Mc reception is best during the hours of
darkness, which are shown shaded in the lower part of the figure.
This is in agreement with the yell-known absorption effect which
makes 5 Mc useful only for a few hundred miles during daylight, but
useful a few thousand miles at night. The cause of the low values
of signal intensity for June and July is not known, but is thought
to be an absorption effect.
Reception of radio station WWVH on 10 Mc at Adak is shown for
twelve months in Fig. 2. It will be noted that for November,
December, January and February, reception is best for a period of
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Table I
CAA Data Taken from CRPL Report Forms
Locality
West Coast
Alaska
Pacific Islands
Frequency,
Mc
5
10
35
No.
%
5
lo
15_
No.
%
5
10
15
No.
%
Better
182
187
124
493
20.0
1708
2044
1993
5745
67_.2
549
787
873
2209
87.6
Worse
11
68
40
119
1.5
Same
464
798
704
1966
80.0
523
1110
1042
2675
31.3
- 71
115
128
314
12.4
Totals
646
985
828.
2459
2242
3222
3075
8539
62o
902
lool
2523
Table II
FCC Data Taken from CRPL Report Forms
Locality
East of Rocky Mts.
West of Rocky
Mts.
Fort Hase, Oahu, T.H.
Frequency,
Mc
5
lo
15
No.
%
5
lo
15
No.
%
5
lo
15
No.
%
Better
13
23
45
81
2.4
121
125
106
352
29.9
157
86
17
260
54.6
Worse
2
7
8
17
0.6
1
o
1
2
0.2
Same
1005
1256
953
3214
97.0
215
319
288
822
69.9
27
84
105
216
45.4
Totals
1020
1286
1006
3312
337
444
395
1176
184
170
122
476
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a few hours starting a couple of hours before sunset. The curve for March
shows an extension in the number of hours to about eleven when reception
is useful. Reception in April was useful about 15i hours. In May recep-
tion began about 11- hours later than in April and dropped off hour
earlier. June, July, September and October showed reception consistently
weak and unusable.
Reception of radio station WWVH on 15 Mc at Adak is shown for
twelve months in Fig. 3. It will be noted that for November, December,
January, February and March the hours of reception were approximately
those when 5 Mc was not received. The curve for April shows a ten-
dency for improved reception during previous silent hours, but reduc-
tion in signal intensity after daybreak. The months of May, June, July
and August shaved excellent reception throughout the 24 hours.
September and October show a lowering of signal intensity presumably
leading to curves similar to the November, December curves previously
mentioned.
Strongest reception of radio station WWV on 20 Mc at Adak was ob-
tained during January, for which the curve is shown in the laver corner
of Fig. 3. During the other eleven months for which data were sub-
mitted) the station was not heard or the intensities were much below
the curve shown for January.
Examination of the data given in the three sets of curves for
station WWVH shows that for almost any hour in the twenty-four at least
one of the three frequencies was heard with an intensity of 3 or higher.
Exceptions were poor reception in April for a few hours after sunrise
and in September for a few hours before sunrise. Two frequencies were
available a large portion of the time, and three frequencies were heard
with high intensity part of the time.
4. Anchorage, Alaska, Data
Data on the percentage of time the transmissions of WWVH and WV
are at a useful intensity were submitted by the Radio Propagation
Field Station) Anchorage, Alaska, for each month from June 1949
through March 1950. /Data for the first three months were presented
in a previous paper./ and are included in the present report to give
a 10-month reception picture. The observations were made hourly from
150(. or 1700 UT to 0900 or 1100 on 5, 10 and 15 Mc, and varied from
10 to 31 observations per month for each hour. Data for some hours
of some months were quite similar, so that mean values were plotted
for such times and the curves were appropriately marked. Curves not
marked are either average values for the 10-month period or for that
portion of the period not covered by other curves.
7/ Coverage of Standard Frequency Station WWVH, March-October, 1949,
-E. L. Hall, Report CRPL-8-4, Dec. 28, 1949; Television Eng. 1, No, 8,
16-18; No. 10, 20) 27, 1950.
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Fig. 4 shows the 5-Mc reception at Anchorage of both WWVH and WWV
with times of sunrise and sunset at the three localities plotted for
each month. Reception for June appears to have been quite satisfactory.
WWV came in earlier and with greater intensity, than WITH, as sunset is
from 4 to 5- hours earlier at WWV. It will be noted that beginning
with June, reception comes earlier each month through January, except
for October, and then cones later each month. The data for September
indicate greater intensity than for the succeeding month so that they
do not fall in line with the other data.
The curves for 5-Mc reception of WWVH are similar to those for
WWV, but reception occurs later. Accordingly it is useful for a
shorter time than WWV (9 hours versus 13 hours for WWV in January).
Fig. 5 shows the 10- and 15-Mc reception at Anchorage. The 10-Mc
reception from WWVH seems to be more variable with season than that
from WWV. There is a definite increase in the hours of reception of
WWV beginning with June and extending until January, when the recep-
tion period begins to decrease.
The upper curves of Fig. 5 show the 15-Mc reception at Anchorage.
Seasonal effects are apparent. WWVH appears to be useful for a longer
period in the day than WWV.
5. Data from Los Angeles, California
An observer in Los Angeles, California, made a large number of
observations of reception of WWVH and WWV from late March through
September, 1950. These observations provided data except for the
late evening and early morning hours. As there appeared to be very
little seasonal change, all data were averaged and curves plotted
for the different frequencies of WWV and WWVH against hours UT as
in Fig. 6. Times of approximate sunrise and sunset are also shown
for the two stations and Los Angeles for the period under considera-
tion.
Referring to the curves for 5 Mc, it is seen that WWV comes in
before sunset at Los Angeles and reaches a maximum after dark. WWVH
comes in about three hours later. It presumably maintains a strong
signal throughout the night until an hour after daylight, as it is
still night at the station. WWV's signal, however, was zero because
of the earlier sunrise at WWV. Los Angeles is beyond the reach of
the 5-Mc transmissions during most of the daylight hours, being
approximately 2300 and 2500 miles from WWV and WWVH, respectively.
The 10-Mc transmissions of WWV are usable in Los Angeles most
of the time except for a period of about nine hours starting about
an hour after sunrise. WWVH's 10-Mc transmission is similar except
the unusable period starts an hour or so later.
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The 15-Mc transmissions of WWV'have greater intensity than those of
WWVH. This is not surprising when one considers that the powers have a
ratio of 22:1 and the distances are similar. The curves indicate that
WWV's 15-Mc transmission is useful during the daylight hours when the
5 and 10-Mc transmissions are not received satisfactorily.
Curves for WWV's 2.5 and 20-Mc transmissions are shown at the tdp
of Fig. 6. Unfortunately data are lacking to show how long the 2.5-Mc
transmission is received after dark. However, it is probable that it
can be received as long as most of the transmission path is in darkness.
This transmitter has 0.7-kw output. The 20-Mc transmission was received
during daylight hours, but is less dependable than at the lower fre-
quencies.
6. Data from South Australia
Observations were made by an individual for ten months on the re-
ception of stations WWVH and WWV on 5, 10 and 15 Mc at Huddleston,
South Australia. Some of the data were given in the previous report
showing reception from July to October, 1949. The data received since
that time are presented in Fig. 7 where signal intensity on a 0-9
basis is given for the two stations and three frequencies on a 24-
hour basis. The lower part of the figure shows the sunrise and sunset
times (UT) for Huddleston, WWVH and WWV. It was convenient to divide
most of the data into two periods, October, 1949, to February, 1950,
inclusive, and May to,August 1950. Data for March and April, 1950,
were not supplied. Averages were accordingly determined and plotted
as shown in the figure. The 15-Mc August data were so radically dif-
ferent from those for May, June and July that a fifth curve was
plotted.
Examination of the 5-Mc curves for WWVH shows no seasonal dif-
ference. Reception begins near sunset at Huddleston and drops out
about the time of sunrise at the transmitter. The 5-Mc transmission
from WWV shows a 2-hour difference in the building up of signal in-
tensity with the May-August signal coming in earlier. This is be-
cause of the earlier sunset at Huddleston for these months. The
most intense signals from WWV are received during the two hours when
the transmission path is in darkness. The transmission path from
WWVH is in darkness from six to seven hours during which signals
from WWVH are heard. The signal intensities on 5 Mc are below those
on the higher frequencies and the data demonstrate the futility of
this frequency for day transmissions over long distances, and its
dependence upon darkness over the transmission path for reception
at great distances.
The 10-Mc curves of Fig. 7 show much higher field intensities
than the 5-Mc curves and also a seasonal effect. WWVH's intensity
increased from zero following sunset at the transmitter and main-
tained a strong signal during the hours of darkness at Huddleston
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when observations were made. It was not heard during the morning and
early afternoon hours.
WWV's reception shows two periods of increased intensity with
periods of nonreception in between. WWV begins to core in a few hours
before sunset at Huddleston (night at transmitter), reaches a maximum
and slowly falls to zero a few hours after, sunrise at the transmitter
(night at Huddleston). It is again heard with lesser intensity for a
few hours, part of which have a daylight path.
The 15-Mc curves for WWVH show a more intense signal for the
October-February period than for the May-August period. Signal in-
tensity of S5 or higher is seen to be available for 10 hours for the
former period and about 6 hours for the latter.
The 15-Mc October-February curve for WWV shows maximum intensity
soon after sunset at the transmitter (morning at Huddleston), falling
to zero in about 5 hours. The intensity built up again and held at a
low value as long as the observations were continued(until about
midnight). The May-July curve shows greater intensity over a longer
period with the peak occurring 17 hours earlier than in the October-
February period. A signal intensity of S5 is available for about
3i hours. The curve for August builds up to S5 for an hour but much
of the remaining time has less intensity than in the May-July period.
If an intensity of S4.is taken as a minimum for reception, it is
seen that the 5-Mc transmissions are not satisfactory. However, the
10 ?Ild 15-Mc transmissions are useful a considerable part of the day.
The advantage in having station WWVH is evident from the curves and
the following Table 3. The difference between the total hours shown
and hours for WWV indicates the improvement in reception because of
WWVH.
7. Data from Kingston, Jamaica
Data were submitted on a QSA5 basis for reception of WV and
WWVH as observed by an individual at Kingston, Jamaica. Observation
times were 7:00 a.m., 1:00 p.m., and 7:00 p.m., EST, which is the
same as Jamaica time. The period covered was from February through
November, 1950. The data for each frequency from each station were
averaged for each month and are'presented in Table 4. Kingston is
about 1470 miles from WWV and 5200 miles from WWVH. Trial observa-
tions on 5 Mc at 1:00 p.m. were without success, as daylight paths
existed for both transmissions.
The 54Mc transmission from WV at 7:00 p.m. showed a maximum
intensity when sunset had occurred at WWV and Kingston an hour or
more before the measurements. The data are given in Table 5. As
the sunset occurred later in succeeding months at WWV and the mea-
surements were made nearer and nearer sunset time, the signal
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intensity dropped, but increased again as the sunset became earlier
at WWV. The 7:00 a.m, measurements were made after sunrise for both
points and showed a rather low signal intensity.
The 5-Mc transmission from WWVH was received with low intensity
at 7:00 a.m. It was daylight in Kingston but night at WWVH. The
signal intensity, averaged about QSAl.
Table 3
Hours per Day with Average Signal Intensity
S4 or Higher at Huddleston, South Australia
Frequency, Mc Season WWVH WWV
5 0 0
10 Oct.-Feb. 10i 7
May-Aug. 10 9i
15 Oct.-Feb, 111
r2-
May-Aug. 8- - )
May-July - ai)
r-
- August 3.- )
. Total
0
10t
12f
14
91
2
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Table 4
Average Estimated Signal Intensities of WWV and WWVH at
Kingston, Jamaica, February to November, 1950. (QSA-5 basis)
r-i
Freq.
Mc
Station
Feb.
March
April May June July
1200 UT 7:00 a.m. EST)
Aug.
Sept.
Oct.
Nov.
5
WWV
1.2
2.7
2.0
1.6
1.8
1.4
1.4
1.5
1.5
2.2
C-1
5
WWVH
0.8
1.1
1.2
1.1
1.0
1.1
10
WWV
4.2
4.8
4.6
4.7
4.9
4.8
4.7
4.6
4.2
5.0
L-J
10
WWVH
2.2
3.2
3.6
3.4
3.7
3.9
3.8
3.3
3.3
1.7
("1
15
WWV
3.9
3.9
3.8
3.3
3.6
3.2
3.0
3.1
2.9
3.8
L.-11
15
WWVH
1.7
1.8
2.1
2.2
2.4
2.2
2.0
1.3
1.4
0.6
1800 UT (1:00 p.m. EST)
10
WWV
3.6
3.6
2.5
2.8
3.7
3.5
3.1
2.8
3.8
-J
15
WWV
4.4
3.8
3.4
4.0
3.3
3.3
3.3
3.8
4.3
0000 UT (7:00 p.m. EST)
5
WWV
2.9
3.5
2.3
1.7
1.9
1.7
2.2
2.9
3.4
3.6
10
WWV
4.7
4.9
4.6
4.9
4.9
4.7
4.7
4.6
4.5
4.5
I._.J
10
WWVH
3.1
2.4
2.4
2.0
1.5
1.0
0.9
1.4
1.5
1.4
15
WWV
4.5
4.2
4.0
3.8
3.6
3.2
2.7
2.2
1.4
1.7
16-.J
-1
15
WWVH
2.6
2.0
1.8
1.8
1.8
1.3
1.1
1.0
0
0
LU
LU
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Table 5
Avera :e Estimated Signal Intensit of WV 5 Mc at Kin ston Jamaica
._t_vL2O_=li22t_Ewi.ffect of Sunset Times on
Signal Intensity
?Month Average Sunset, Hours UT Difference between Aver.
1950 Kingston WV Sunset and Time of Meas.
Hours
Average
Sig.Intensity
(QSA Scale)
Feb.
22.9
22.8
1.2
2.9
March
23.1
23.2
0.9
3.5
April
23.2
23.8
0.5
2.3
May
23.4
0.2
0.2
1.7
June
23.6
0.5
0
1.9
July
23.6
0.5
0
1.7
Aug.
23.4
0
0.3
2.2
Sept.
23.0
23.2
0.9
2.9
Oct.
22.6
22.5
1.5
3.4
Nov.
22.3
2200
1.9
3.6
The data indicate that the 10-Mc transmissions were stronger than the
l5-Mc transmissions for both WWV and WWVH, but WV was stronger than1WWVH:
as would be expected.
III. Reception of Other Standard Frequency Stations
1. Observations of 5-Megacycle Standard Frequency Transmissions from
JJ, Tokyo, and WWVH, Maui, Hawaii,
About 1000 observations were received from the U.S.Navy's Communica-
tion Station at Guam on the 5-megacycle standard frequency transmissions
from radio station JJY, Tokyo, Japan, and VWVH, Maui, Hawaii, covering the
period November 26 through December 7, 1949.
Station JIY was operated with a power of 1 kw on 5 Mc for the period
from 0058 UT November 18 to 0700 UT December 8, 1949, under Sponsorship
of the Supreme Commander, Allied Powers. Each hour of the twenty-four
was made up of the following emissions and silent periods:
0-10, 20-30, 40-50 minutes, 1000-cycle modulation
10-18, 30-38, 50-58 minutes, off the air
18-20, 38-40, 58-60 minutes, voice announcements, call letters,
in Japanese and English.
Station WWVH was operated with a power of 0.4 kw on 5 Mc prac-
tically continuously during the period of test except for the following
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ri
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?
?
,
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regular interruptions: each hour, 0-4, 30-34 minutes, off the air; each day,
0700-0734 and 1900-1934 UT/ off the air. Station WWV, Beltsville, Maryland,
operated continuously, but as it is 8000 miles from Guam, its 5-Mc trans-
missions were probably received there with low intensity.
The time schedule used by JJY was excellent to enable observers to
monitor JJY and WWVH together and separately. The data consisted of
from 80 to 90 observations per day for 12 days, reported on the signal
intensity using the QSA5 scale. They were plotted for each day with
respect to time, and an average was obtained for each hour. Station JJY
was approximately 1600 miles from Guam, while WWVH was about 4000 miles
eastward. The records stated that on some days JJY's,1000-cycle tone "blocked
out WWVH completely." It is believed that suitable directional antennas
would enable either JJY or WWVH to be received satisfactorily at Guam
during hours of darkness, as the two transmission paths for these sta-
tions are practically at right angles'.
The average received signal intensities for JJY and WWVH were
plotted versus time in Fig. 8. Hours of darkness (sunset to sunrise)
were also shown for Guam and the two radio stations. The correlation
between the signal intensities for 5 Mc and the hours of darkness is
well shown. The distance from Guam to WWV is about 8000 miles, which
is too great for reception of 5 Mc. However, the hours of darkness at
WWV are also plotted to show that there is no correlation as exists
for the two closer stations.
Many other observers in the United States spent time endeavoring
to monitor JJY, but without much success. This was partly because of
erroneous announcements of transmission schedule. However, examination
of the chart of darkness hours for JJY and WWV indicate that the most
likely time to have heard JJY on the vest coast was from about 1200
to 1500 UT. WWV would be dropping out on 5 Mc about 1200 and for three
hours JJY might have been heard. Localities farther east would have
had less time for successful monitoring.
A large number of observations were made at many localities in Japan
during these special transmissions. The results were made available
through the Department of the Army. ?A high hoise level prevails in Japan
so that reception of WWV is unreliable and WWVH is heard consistently
only a few hours of the night. The efforts in Japan were therefore
largely directed to measurements of signal intensity, noise and inter-
ference at the various observation points. When WWVH was observed its
intensity was far below that of JJY being from 3900 to 4600 miles from
the Japanese observation points. The greatest distance of the Japanese
points from JJY was about 600 miles. Conclusions were drawn in the re-
port that JJY's 5-Mc transmission was adequate for a 125-mile radius,
both day and night, but beyond this afternoon field intensities were
unreliable.
These conclusions seem somewhat restricted in' terms of data which
have been obtained with station WWV and other results reported for WWVH.
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The prevailing noise level and other interference at a given location or
ma given ,region are the chief limiting factors in reception at this fre-
quency and hence extremely limited coverage may result. Others of the
well-known factors affecting reception may also play a part, so that any
estimates or predictions of results to be expected at a given locality
are subject to change in accordance with experimental results at that
location. From hitherto unpublished results on certain special trans-
missions of WWV in 1935-6 during the day, 50% intelligibility of dis--
connected words was obtained up to 230 miles in June, August, and September,
and up to 560 miles in December, using 1 kw of power. WWVH is heard
several thousand miles at night. It appears that the Japanese area is plagued
with a natural interference barrage in addition to the interference from
many stations which do not adhere sufficiently to international frequency
assignments. One recording of WWVH and JJY on 5 Mc in Japan showed a beat
frequency between the two stations at times. Agreement between the sta-
tions was better than a part in 107 for a period of seven hours. In the
following two hours WWVH's frequency was indicated different by as much
as 9 parts in 107, but in a random manner. The sunrise or sunset period
at a control point in the radio propagation path should be avoided if
highest accuracy is desired. As the ionosphere layers begin to change
in height with the coming of daylight or darkness the transmission path
is altered, resulting in fluctuations in the received frequency known
as the Doppler effect. It is therefore evident that small beat fre-
quencies may be introduced in spite of maintaining two stations very
precisely in synchronism and may be detrimental to some users of WWV
and WWVH.
The frequency of the audio modulation also changes by small
amounts, sudden phase shifts being quite noticeable when monitored
against a steady local source. Reception of the same audio fre-
quency from two stations at about the same intensity, when the Doppler
effect is in evidence, would make use of the audio frequency difficult.
In such a case it would be desirable to use a directional antenna, if
possible, to cut out reception of the station showing the greater
change. Otherwise monitoring of the standard audiofrequency would
have to be greatly prolonged in order to average out the frequency
changes and obtain a more accurate value.
2. Standard Fre uency Transmissions from MSF Rugby En land
The Federal Communications Commission submitted reports from
twelve of their field offices scattered throughout the United States
and one office in Hawaii covering reception of the English standard
frequency station Ma', England, operating approximately half an hour
each day on 5 and 10 Mc with a power of 10 kw. The time and duration
of these transmissions were such as to afford a minimum of inter-
ference with WWV and WWVH transmissions and are shown in Fig. 9.
The detrimental effect (if any) of three standard frequency sta-
tions operating simultaneously on the same frequency was accordingly
more difficult, if not impossible, to evaluate.
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The MSF 5-Mc transmission was as follows:'
0544 UT for one minute, call letters, voice announcement;
0545 for five minutes, 1000-cycle modulation;
0550 for nine minutes, carrier only;
0559 for one minute, call letters, voice announcement;
0600 for five minutes, 1000-cycle modulation;
0605 for nine minutes, carrier only;
0614 for one minute, call letters, voice announcement.
The MSF 10-Mc transmission was divided in a similar manner, with
the first announcement beginning at 0629 UT and the last one at 0659 UT.
For American observers these transmissions came between the hours 0044
and 0200 am, EST, or 0944 and 1100 pm, PST. The call letters and voice
announcements came at the same time as the announcements of WWV and
WWVH. The 1000-cycle modulation was on at the same time as the 10
cycle or 600-cycle modulations of WWV and WWVH. When MSF was heard
the 1000-cycle modulation could be distinguished along with the modula-
tion from WWV. The periods with the carrier only apparently were not
heard, so contributed to rather meager reports of reception. The
distance range involved for continental United States was from ap-
proximately 3300 to 5500 miles.
The 5-Mc transmissions were heard faintly in Massachusetts,
Georgia, Michigan, Texas and Idaho. Georgia reported the 10-Mc
transmission usable on three days, and the other eleven U.S. locali-
ties reported various degrees of weak reception from "1000-cycle modu-
lation heard, but voice not understandable" to "heard very weakly and
unusable with WWV and WWVH operating." It was heard very weakly at
Fort HaselOahul T.H.
An observer in South Australia has heard MSF on 10 Mc a number
of times during May, July and August. His rating of signal intensity
for MSF, WWV and WWVH was 2, 5, and 7, respectively.
One or two of the observers demonstrated reception of the 1000-
cycle modulation on an oscilloscope while WWV had its 440 or 600-
cycle modulation on. Other observers were sure of the identity Of
the station only during the portion of a minute when WWV was silent.
In view of the above reports there seems to be very little use
in making further observations in the United States on MSF under its
present limited time schedule. It would appear that the 5-Mc trans-
missions should have been received more strongly than reported, as
they had an all-darkness transmission path to the United States.
Reception for a half-hour period might be difficult because of
local conditions, but improve at a later time.
Conclusions drawn from these tests at this time are that MSF
does not interfere with stations WWV or WWVH as used in the United
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States. What the conclusions may be for observations in the British Isles,
Europe and Africa are unknown, but in any event, it would appear that the
times of transmirsion are too short to evaluate them in terms of a world-
wide standard frequency service.
IV. Discussion
Most of the reports of reception of WWVH and WWV indicated no mea-
surable beat between the carrier frequencies or audio frequencies as
broadcast, so that no detrimental effects were noted caused by operation
on identical frequencies. However, it is probable that very few of the
observers had facilities for the determination of a small frequency dif-
ference if such existed. It should be noted that varyin terms of
measure-
ments and adjustments were made twice daily at WWVHD of WWV so
as to maintain the seconds pulses and frequency in synchronism. Special
precautions were taken in this work which are not usually necessary
except in work of highest accuracy.
Observers in Government agencies such as the Federal Communications
Commission had facilities for measurements of small frequency differences.
A report from the Postmaster General's Department, Commonwealth of
Australia, for the five monitoring centers, Perth, Adelaide, Melbovrne,
Sydney, and Brisbane, indicated no interference between WWVH and WWV.
WWV is about twice as far distant from these cities as WWVH, being
almost half-way around the globe.
Some of the reports from a few of the FCC field stations at times
indicated beat frequencies from a fraction of a cycle to 2.5 cycles for
some periods on 10 and 15 Mc. Later the beat was not present. At times
it was identified and disappeared when WWVH shut down for its periodic
silent periods. The beat was particularly noticeable on occasions when
the two stations were received with equal intensity. At other times the
beat was found to drift to zero. Fading also produced a beat effect at
times so that it was difficult to distinguish between the fading and a
frequency difference between the stations.
Under suitable receiving conditions it is possible to receive the
seconds pulses on one or two of the carrier frequencies both ways around
the earth. These pulses as received seldom coincide. The pulses trans-
mitted from WWV and WWVH are sent at nearly identical times; the two
pulses will not arrive at a receiving point at the same instant if the
receiving point is nearer one station than the other, as was the case
for those observing this effect.
Theoretically the beat effects described above may be expected
but, as some observers pointed out, their absence was surprising.
Generally speaking, beat frequencies and phase shifts may be expected
when receiving two widely spaced stations operating on identical fre-
W Adjustment of high-precision frequency and time standards, John M.
Shaull. Proc. IRE 38, 6-15, January, 1950.
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quencies. At times these effects may be serious and at other times non-
existent. Shifting to other standard frequencies or the use of directional
antennas may largely overcome undesired effects.
V. Conclusions
The data presented verify past experience with the standard fre-
quency transmissions as to propagation characteristics. These may be
briefly summarized as follows. The 5-Mc transmissions are generally
useful for shorter distances during daylight and a few thousand miles
at night. The 10-Mc transmissions are useful for longer distances and
show no such pronounced attenuation or absorption with daylight as is
manifested by 5 Mc. Directional antennas may be a necessity at some
locations if satisfactory results are to be obtained. The 15-Mc trans-
missions are useful for distances from a few hundred to 8,000 or,
10,000 miles, day or night. Seasonal effects) changes in sunspot
numbers) ionosphere disturbances and local conditions of atmospheric
and man-made electrical noise affect reception ranges. The data are
to be interpreted in terms of a drastic change in solar activity, as
evidenced by the 12-month running average Zurich sunspot number, which
was 137 for June, 1949, and 68 (estimated) for November9 1950. The
months from June, 1949, through July, 1950) may be considered roughly
to be part of a period of high solar activity, whereas the months be-
ginning with August, 1950, represent medium solar activity. There
was a sharp decline in the monthly average Zurich numbers beginning
with September, 1950. The effect of decreased solar activity is in
the direction of a layering of critical frequencies and, almost
without exception, optimum traffic frequencies for a given trans-
mission path. Results to be expected at a given location on the
several standard frequencies may be estimated from the information
given herewith. The best frequency or frequencies can be determined
by trial.
Station WWVH has been in operation for a period of two years on
an experimental basis with law power. It has been found to supplement
the standard frequency and time service coverage of station WV, par-
ticularly in the Pacific and Alaskan areas, without introducing unde-
sirable interference. It is likely that-iiicreased power at WWVH
would further extend the coverage and also give more definite data
on the seriousness of beat frequencies sometimes observed.
The operation of station JJ Y on 5 Mc for a limited period was
insufficient to get the desired experimental results; however) opera-
tion of the station would undoubtedly increase the standard frequency
coverage for the Far East. ?
Station MSF operates on 5 and 10 Mc at such a time of day and for
such a short period that its effect upon WV transmissions is of no
consequence in the United States. The effect in Europe has not been
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published. If the station should operate for longer periocl.s such as for
24 hoUrs one or two days per week, considerable interesting information
could be obtained in the United States.
VI. Acknowledgment
The work of the individuals in the various agencies and elsewhere
who provided the extensive data used in preparing this report is
gratefully acknowledged.
fl
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4
2
8
6
4
.71/
? SEPT '50
?X OCT '50
X
? MAR '50
X APR ?'50
0 MAY '50
A JUNE 50
V JULY '50
e AUG 50
0000 0400
JAN
MAR
MAY
JULY
SEPT
NOV
JAN
0800
1200
HRS. UT
1600
? NOV. '49
X DEC. '49
0 JAN. '50
A FES. '50
2000
2400
SUNSET
ADAK WWVH
SUNRISE
WWVH ADAK
C
C
FIG. I. RECEPTION OF WWVH ON 5 MC AT ADAK, ALASKA, NOV. 1949
THROUGH OCT. 1950
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Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
INTENSITY
8
6
4
2
8
6
4
-I 2
4
./10.????
(:) AU G 50
? SEPT '50
X OCT 50
--- X ?X X--X
? MAR '50
X APR 50
0 MAY '50
A JUNE 50
V JULY 50
8
6
4
2
? NOV 49
X DEC '49
OJAN '56
A FEB '50
x-
0000 0400 0800 12 1600 2000 2400
HRS: UT
FIG. 2. RECEPTION OF WWVH ON 10 MC AT ADAK, ALASKA, NOV. 1949
THROUGH OCT 1950
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cj 1 r) r 1 rl r1 r1 r ri ri ri ri r
Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
SIGNAL INTENSITY
8 -......---...
6.023t.'??? X ?Nt........????...
' ? *??%.
4 --......--N.
x .
2 , x"--x--x_x?x__xNix?x?x?f:.%
ii '-r ?? ? ?
8
6
4
2
8
6
4
2
4
? SEPT '50
(OGT '50
? MAR '50
X APR '50
0 MAY '50
A{JUNE '50
JuLY '50
? AUG '50
? NOV '49
X DEC 49
?C?"C)-4>.'0..
..ck 0 JAN '50
1 wwv
520 Mc A FEB 50
0000 0400 0800 1200 1600 2000 2400
HRS. UT
F1G.3. RECEPTION OF WWVH ON 15 MC AT ADAK, ALASKA, NOV. 1949
THROUGH OCT. 1950 (WWV ON 20 MC JAN. 1950)
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Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
100-
80
60-
5" 40
-71 20-
o
(n 1600? ? ? 2000
00 GO
0400
HRS. UT
5Mc WWV
0800
1200
1600
JUNE
APR
9 FEB
7 DEC
5 OCT
3 AUG
1 JUNE
F1G.4.
SUNSET
WWV WWVH ANCH.
SUNRISE
WWV ANCH. WWVH
toil ?" ' IkaP ' gird!,
II 1 k _ 0 , et 6 " .. S?
V 0 ? - .? 4
.4...... .1.44%.%, t. . ..
\
N..,NV 4o.4 0?
*-4?47?ir ' NSW.
.4 6 .
?'N7.,:.-
, 4'? 4.0*-? ?
5-MC RECEPTION OF WWVH AND WWV
JUNE 1949 - MARCH 1950. SUNRISE AND
FOR THE THREE LOCATIONS.
MAY
10 MAR
6 JAN
6 NOV
4 SEPT
- 2 JULY
AT ANCHORAGE, ALASKA,
SUNSET TIMES SHOWN
r 1 r 1 r-1 r Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4 1 i ri ri n
[j cj [ 1 ri r 1 ri r-1 1.1 r i r i r 1 Cl Cl Cl [i EJ
Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
15 Ma WWV, WWVH
1
100
80
60
40
20
i9mc wwyH
1600 2000 0000 0400 0800 1200 1600
1 JUNE
2 JULY
3 AUGUST
HRS. UT
.
4 SEPTEMBER, 7 DECEMBER
5 OCTOBER 8 ,JANUARY
6 NOVEMBER -9 FEBRUARY
10 MARCH
FIG.5. 10- AND 15-MC RECEPTION OF WWVH AND WWV AT ANCHORAGE,
ALASKA, JUNE 1949- MARCH 1950.
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Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
20 MC
< --< -4C --< 2.5 MG
W WV
OW WVH
5 MC
4
APRIL
SEPT
04
08
12
HRS. UT
'
SS
7.4
LOS ANGELES
W WVH
W W V
SS
FIG: 6. CHART SHOWING AVERAGE RECEPTION OF WWVH AND WWV Al
LOS ANGELES, CALIFORNIA APRIL-SEPTEMBER 1950, ON 5, 10,
AND' 15 MC, AND WWV ON 2.5 AND 20 MC.
3 C C 3I Declassified and ApprovedFor Release 2014/01/29: CIA--RDP78-53153-A6-02000060002-4 I 3
i[ji_j[irlr!r,rirlr!ri.ririr]1JEJLi cic
Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
SIGNAL INTENSITY
8
6
4
2
5 Mc
,--.-->MAY-JULY
< ...--
5, >17----v AUGUST
e3WWVH OCT?FEB
0WWVH MAY?AUG
< W V OCT?FEB
>W WV MAY?AUG
JAN
MAR
MAY
JULY
SEPT
NOV
JAN
VH H V VH H V
SS SS SR SR SR SS
FIG.1 RECEPTION OF STATIONS WWVH AND WWV AT HUDD\ESTON,
SOUTH AUSTRALIA, OCTOBER 1949 TO AUGUST 1950.
WWVH 5600 MILES
APPROX. DISTANCE HUDDLESTON TO
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r
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I- 5-
i 4
t- 3-
z
- 2
90dl
u) 0000
00000000000
0
0 0 0
o JJY
0 WWVH
GUAM
?
0 0 0
0400 0800 1200 1600 2000 2
HRS. UT
SS
V../////Z/Z7Z-77//////////1
SR
SS///
E:=7Z72ZZ122:Z=EZ:=222211SR
SS
1%//////X//////yr//// //SR
0
wwv r- 8000 MI
MAUI WWVH 3950 MI
TOKYO JJY 1600 MI
GUAM
FIG.8. RECEPTION OF WWVH AND JJY AT GUAM NOV. 26 TO DEC. 7,1949.
Declassified and -Approved For Release 2014/01/29: dIA-1-kIDP8-63153A0-0206006-0002-4-
1 flH 1r -;T 1 r 1 ri r 1 r7 7
- Declassified and Approved For Release 2014/01/29: CIA-RDP78-03153A002000060002-4
\--CALL LETTERS, VOICE ANNOUNCEMENTS
It.7-2
MSF
1000rv
2
?4
5 Mc-. 0545
I
10 Mc-.0630
CARRIERI ONLY
7
1000rv
CARRIER ONLY
0550
0555
0600
0605
0610
I
1
I
1
0635
0640
0645
0650
0655
5 Mc 440ev 600rv 440rv
W W V 911E1
WWVH
0615
1HOURS, UT
0700J
440 rv L 600t1,
IO Mc?i.60041 440nr 60O' 440^, 600 rv 440tv
WWV TIME, PROP.
10 ANNOUNCEMENTS,
VOICE ,
\WWVH TIME AND
CALL LETTERS
FIG.9. CHART SHOWING STANDARD FREQUENCY TRANSMISSIONS OF MSF
ON 5 AND 10 MC AND RELATION TO MODULATIONS OF STATIONS
WWV AND WWVH.
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