Amateur Observations During the Total Eclipse of the Sun
January 1933, QST
radio operators, as with hobbyist participants in many other realms,
historically have contributed significantly to the efforts of their
professional counterparts. I have written of it often. This particular
instance is where signal measurements in the Ham bands during a
total eclipse of the sun were used to assist scientists debating
the merits of rival theories relating to origin of ionization in
Kennelly-Heavyside Layers of the E and F regions, both of which
were proposed in 1902 (yes, the Heaviside of
step function fame). Long distance (DX) communications are dependent
upon such ionization to reflect radio signals that would otherwise
pass through the atmosphere and into space. The test at hand would
settle the argument since the one should fail if ionization was
unaffected during totality. Read the article (or skip to the end)
to discover which gentleman's theory won the day.
January 1933 QST
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present. All copyrights hereby acknowledged.
During the Total Eclipse of the Sun
By R.W. Woodward, W1EAO
The total eclipse of the sun on August 31, 1932, afforded a wonderful
opportunity for the radio amateur to contribute to our scientific
knowledge of short-wave transmission phenomena, and more particularly
to obtain information which would lend support to one or the other
of two rival theories concerning the origin of the Kennelly-Heavyside
EQUIPMENT USED AT THE CASE SCHOOL OF APPLIED SCIENCE, CLEVELAND,
FOR GRAPHICAL RECORDING OF THE SIGNALS OF W1EKL
The output of the receiver was fed though a vacuum tube
voltmeter to the standard Leeds and Northrup recorder with
paper speed stepped up to record rapid variations. This
work was under the direction of J. R. Martin, Assistant
Professor of Electrical Communications. assisted by W. E.
Slabaugh, W8CIM. and L. W. Fraser. W8DGP. Thanks are due
to MT. Fraser for this information, including the photographs
and copy of the recording shown in Fig. 6.
One theory supposes that the ionization of the reflecting
layers (both the so-called E and F layers) in the upper atmosphere
is caused, for the most part, by ultra-violet light from the sun.
The other theory holds that the ionization of the lower, or E layer,
is produced by neutral particles or corpuscles streaming from the
sun at a rate of a thousand miles per second. If the first theory
is tenable, any effect on radio transmission during the eclipse
should correspond approximately with the time of the visible eclipse.
On the other hand, if the corpuscular theory is acceptable, the
effect on radio propagation should precede the visible eclipse by
some two hours due to the slower velocities of the corpuscles coming
from the sun as compared to the speed of light. Whereas the visible
total eclipse cut a swath only about 100 miles wide across a part
of New England and eastern Canada, the "corpuscular eclipse" would
be maximum on a path starting from Spitzbergen, through Greenland,
the mid-Atlantic Ocean, and ending at lower Spain. It would cover
a path about 1600 miles wide, not touching the United States.
Equipment used at the Case School of Applied Science, Cleveland,
for graphical recording of the signals of W1EKL. The output of the
receiver was fed through a vacuum-tube voltmeter to the standard
Leeds and Northrup recorder with paper speed stepped up to record
rapid variations. This work was under the direction of J.R. Martin,
Assistant Professor of Electrical Communications, assisted by W.E.
Slabaugh, W8CIM, and L.W. Fraser. W8DGP. Thanks are due to Mr. Fraser
for this information, including the photographs and copy of the
recording shown in Fig. 6.
As requested in QST, by Official
Broadcasts and by letter to Official Observers, a great many A.R.R.L.
members all over the country and in some European countries sent
in reports to head-quarters on their observations during the eclipse.
Particular attention was directed to the transmissions of W1EKL,
a portable station located at Douglas Hill, Maine, in the path of
totality by a party from the Warner & Swasey Observatory of
Cleveland, Ohio. Prior announcements indicated that this station
would transmit c.w. on 3550 or 7100 kc. between the hours of 1400
G.C.T. (9 a.m. E.S.T.) and 2300 G.C.T. (6 p.m. E.S.T.), but implied
that the 80-meter (3550-kc.) wave would be used. Observations on
intensity of received signals, preferably by means of a suitable
output meter, throughout the entire period were desired. On the
day before the eclipse it was determined that the 80-meter signal
was not strong enough for automatic recording in Cleveland, so that
it was necessary to use a frequency in the 40-meter band. Actually
during the eclipse transmission a frequency of 7150 kc. was used.
Because of this change in the frequency practically no reports on
reception of W1EKL were received at headquarters as many of the
reports indicated that watch was kept for W1EKL on 80 meters. Also
because of skip distance the station on 40 meters could not be heard
in the eastern part of the U.S.A. It is understood, however, that
very satisfactory automatic records were obtained in Cleveland and
also that many reports of reception were received direct by W1EKL.
Possibly also many of the eastern observers did as the writer,
who, after spending several days arranging equipment to take intensity
measurements during the eclipse, and in spite of rain at the time,
hopped in the car a few hours before the eclipse and drove to Maine
for a ring-side seat. At any rate, many A.R.R.L. emblems were seen
on the road.
W1BZI operated by F.S. Huddy at Chepachet, R.I.,
where the eclipse was 98% total, made special eclipse transmissions
on 3896 kc. between 1900 G.C.T. and 2100 G.C.T. (2 and 4 p.m. E.S.T.)
and was reported by many observers, several of whom gave very complete
readings from vacuum-tube voltmeters in the output of receivers.
Some submitted reports from privately arranged schedules, others
of reception of commercial stations, and still others logs of scattered
reception of many stations on the air at the time. The data included
results on the 5-, 20-, 40-, 50-, and 160-meter amateur bands, broadcast
band, and long wave commercial. Several also submitted interesting
data on accompanying phenomena such as static conditions, atmospheric
pressure, temperature, clouds, wind, and light intensity.
In spite of the request to take observations throughout the
day, the majority failed to do so, reporting only for a short period
before totality and a still shorter period after totality. This
was important not only from the standpoint of testing the "corpuscular"
theory, but also, particularly on 20 meters where longer distances
were involved, the time of the maximum of the eclipse was quite
different in the several sections of the country. Thus the maximum
of 38% totality occurred in Seattle, Wash., at 1927 G.C.T. (2:27
p.m. E.S.T., 11:27 a.m. P.S.T.), at Tallahassee, Fla., the maximum
of 68% was at 2047 G.C.T. (3:47 p.m. E.S.T.), while the time of
totality in New England was approximately 2030 G.C.T. (3:30 p.m.
following contributed reports on their results to headquarters:
W1 - AFC, AGA, APK, ASP, ATW, AZQ, BBM, CTG, DGC, DIJ, MX, ST, VF;
W2 - BJZ, EB; W3 - AAJ, AXJ, CL, DZ, QL; W4 - ADA, AJS, AYF, PM;
W5 - AAQ, ARJ; W6 - DLV, RJ; W8 - AJ, AJK, ATN, CBF, DED; W9 - ABS,
AKJ, AN, AOG, BN, EGE, EQW, FMX, RS, Chas. E. Dewey, Jr.; VE4EL;
F8RJ; G2JA at sea on S.S. Rangitiki; ON4AU.
The reports received
showed that the following stations were heard during the eclipse
period, many transmitting special test signals. A great many reports
did not list individual stations but classified their results by
districts so that no doubt hundreds of additional stations also
contributed to the results.
W1 - ABM, ABY, ADN, AHK, AKI,
APJ, APK, AT, AVK, AYR, BBT, BCD, BDW, BIC, BGY, BTZ, BWP, BXC,
BZB, BZD, BZI, CAC, CBJ, CKT, CKU, CLH, CMX, CNC, CPC, CPT, CVJ,
CVR, CYN, DIJ, DZF, EKL, FH, GB, HE, HI, JJ, MX, SI, ST, SZ, ZC;
W2 - ABT, AHE, AIS, AWF, BHZ, BJV, BOT, BPV, BRO, BTZ, CJM, COJ,
COK, DNG, DTO, DZ, GO, GT, NV, ZC, ZT; W3 - AGI, ANA, AO, AQI, AQR,
AUA, AXR, AZC, BIN, BLE, BMA, BNB, BOL, BXN, BYN, CDG, CEU, CGU,
CLG, CNU, COZ, CUP, DIR, DR, LA, OA; W4 - ADA, AGD, AJX, APJ, ATS,
AUA, AWP, BIO, BL, BOJ, BQO, DV, GI, OI, OT, QQ, UT; W5 - AAK, ABW,
AOT, ATS, BBR, BED, CAI, COC, JV, LP; W6 - CTM, CXW, DOB, DZZ, USA;
W8 - AFQ, AGU, AHF, AKU, APQ, AZQ, BAS, BM, BOG, BTB, CBF, CBM,
CDY, CI, CIF, CIP, CSH, CTE, CTF, CXH, DHC, DIL, DJV, DMW, DWV,
DYE, ECD, EEN, ELF, EYU, FBT, FGE, FNN, FQE, FXM, GCF, GFI, GFT,
GTE, HEL, HII, SE; W9 - AN, ARK, AUH, BDR, BHH, BOF, CJJ, CME, CMZ,
CNG, DGN, DKL, DYG, ENR, FFA, FKK, FMK, FPA, FWB, FZL, GHX, GJC,
HOS, HPQ, HUZ, HWE, IMB, IPP, IZP, JBM, JBQ, JHL, JJX; AB1; K5AA;
VE - 1EA, 2AW, 2BF, 2GH, 3AQ, 3TT, 9AA; CM - 2FM, 2WD, 8VE; EAR
- 96, 155, 185, 224, 228; F8 - BS, OL, RJ; G - 2BM, 2OP, 2ZP, 5NF,
5OJ, 6CL; HAF3FV; HK1Z; LU3DE; OK2CM; ON4AU; PY2BN; VP2 - DB, DD;
SU1EC; and the following commercials on which listening tests were
made: DGG, FYL, GID, G5SW, HJO, KDKA, KFYR, KKZ, TIR, VE9GW, WAZ,
WEAF, WQP, W2XAD, XDA.
From the mass of heterogeneous data submitted, involving so many
variables, the problem of digesting and condensing the results so
as to put them in a form for simple presentation can well be appreciated.
Some of the variables encountered are time, location and extent
of eclipse at transmitter, location and extent of eclipse at receiver,
frequency of signal, transmission distance, power of transmitter,
intensity of received signal, method of measuring intensity, and
the ever present personal equation including such items as possible
errors in time recording, operation of receiver at optimum sensitivity,
and the estimation of intensity of signal where the R system was
employed. Not the least confusing factor was the failure of many
to report the system of time used.
Fig. 1 - 3500-kc. Band, 90 to 100% Totality
A - Less
than 50 miles.
B - 50 to 200 miles.
C - 200 to 500
The scheme finally adopted
was to show typical graphs of change in intensity of the received
signal plotted against time for several conditions in each of the
amateur bands. The sub-conditions are the extent of the eclipse
over the transmission path, including areas having 90-100% totality,
75-90%, 50-75%, and less than 50%; and the transmission distance,
including local, an intermediate distance where skip effect would
be expected under night conditions, and longer distances up to the
maximum range of the band.
The intensity changes are reported
as decibels above or below a normal level. Where the R system was
used a change in one number, such as from R8 to R7, or R5 to R6,
was considered as a change in received energy of four decibels.
The time ordinate shown is minutes before and after totality (or
maximum extent of eclipse) considering the mean time of the maximum
over the transmission path. For convenience of those desiring to
compare the time with their own observations, the Greenwich Civil
Time is also shown on the basis of totality occurring at 2030 G.C.T.
(3:30 p.m., E.S.T.). At Douglas Hill, Maine, the computed times
of the various phases of the eclipse were: first contact, 1920;
second contact, 2028:47; third contact, 2030:24; and fourth contact,
Fig. 2 - 3500-kc. Band, 75 to 90% Totality
A - Less than
B - 50 to 200 miles.
C - 200 to 500 miles.
All the data were examined and found to agree very well with
the typical curves shown with only scattered conflictions. A few
unusual transmissions were reported but they must be considered
as freaks which so often occur in short-wave work, their occurrence
being increased by the greater number of stations on the air during
the daytime and the extra vigilance of receiving operators.
Cosmic data supplied
by "Ursigram " messages showed that the 24 hours from 1400 G.C.T.,
August 31st, to 1400 G.C.T., September 1st, was classed as a quiet
day as far as terrestrial magnetism data was concerned. The preceding
two days were days of moderate magnetic disturbances, and August
27th and 28th were classed as days of great disturbances. One sun
spot, with a Wolf number of about 8 was visible on August 31st and
passed from the face of the sun on September 2nd. Prior to this,
two sun spot groups had crossed the face of the sun beginning on
August 23rd and reaching a maximum Wolf number of about 24 on August
26th. The aurora displays for the days in proximity to August 31st
were faint to moderate as observed at College, Alaska. Parenthetically
it might be mentioned that the writer has observed on days when
brilliant aurora were visible in New England, accompanied by violent
magnetic storms, that the skip distance was greatly reduced; 15-meter
signals were heard at a distance of 100 miles that under normal
conditions were never heard.
The weather maps for the period
of the eclipse showed a tropical storm progressing inland in the
Gulf States. Rain occurred in the northeastern states, the Gulf
States, and the Middle West. No pronounced isotherms were indicated
for the eastern part of the country but temperatures were mostly
above normal. Pressure was low in the Gulf States and high in the
Middle West. There was no sharp pressure gradient in any part of
the country except in the vicinity of the tropical disturbance.
Scattered thunderstorms occurred over most of the eastern half of
the United States on the afternoon of August 31st. The western half
was mostly clear with temperatures below normal.
data it may be reasonably concluded that on August 31st radio transmission
should have been approximately normal and that marked variations
from normal could be associated with the solar eclipse. From the
many local thunderstorms irregularities in QRN could be expected.
Those observers who mentioned the fact confirmed that transmission
was normal on August 30th, August 31st, and September 1st.
As is usual during the
daytime, there was little activity on this band and too few reports
were received to allow drawing any conclusions regarding any change
in conditions during the eclipse.
A great many reports were received on observations in the 80-meter
band and since the transmission distance was generally such as to
include an area of nearly uniform solar coverage, the results are
easier to interpret. Although both phone and c.w. stations were
on the air with test signals, the best data received were on the
c.w. signals since with the equipment usually accessible to the
amateur it is more difficult to measure variations in intensity
of modulated carriers. The curves shown are for c.w. signals but
are equally applicable to phone transmissions.
Fig. 1 gives
results in the area of 90 to 100% totality, all reports on reception
of W1BZI. The A curves are typical of results at less than 50 miles,
or little more than local distance. The solid line is reception
reported by W1AGA at a distance of 40 miles in the zone of 99% totality,
while the dotted line indicates the readings of W1AFC at 38 miles,
also in the 99% zone but in a different direction from the transmitter.
These show irregular "sunset" effects or fading in the early and
late stages but with a general rise in level at totality. The dotted
line indicates a decided peak lagging behind totality.
B curve records the results obtained by W1ASP at a distance of 75
miles in a zone of 96% totality, and is typical of results from
50 to 200 miles. This distance, which at night would be expected
to show skip on 80 meters, also shows irregular "sunset" fading
but a greater rise in signal strength than the A curves. Lagging
about a minute behind totality was a pronounced clip or tendency
towards skip, for a short interval. This was followed by a large
increase after which the signal rapidly returned to normal volume.
The C curves show results typifying distances greater than 200
miles which is about the maximum distance possible within the limit
of 90% totality which was set for Fig. 1. The full line is the data
reported by W3DZ and W3CL, the dotted line those of W3QL, all in
zone of 93% totality and about 225 miles from the transmitter. Tendency
towards skip is shown in the early phases and after totality. Signal
strength was considerably raised over normal, in this case peaking
about three minutes before totality without a corresponding peak
following. The observations for the dotted line were not taken at
as frequent intervals as for the other curves and hence show less
Fig. 2 indicates results in the area of 75
to 90% totality for the 80-meter band. Curve A was submitted by
W9BN on reception of W9AN at a distance of 44 miles with the eclipse
about 76% total. Irregular fading is shown with peaks of increased
signal before and after the maximum of eclipse and a pronounced
dip between the two peaks, all lagging behind the visible eclipse.
Curve B is a composite of several reports at distances of
50 to 200 miles. It appears to be somewhat parallel to A. Curve
C was submitted by W3AAJ on reception of W1APJ at a distance of
390 miles and the eclipse about 90% mean totality over the path.
Signal strength is well above normal and peaks about seven minutes
after the maximum coverage of the sun. In addition to this curve
C, in the 75 to 90% zone R6 signals were reported at 600 miles,
R3 at 800 miles, and DX of 1000 miles at the greatest extent of
In the area of 50 to 75% totality, insufficient
data were obtained to admit of plotting, but the individual reports
showed results similar to the 75-90% zone but to a lesser degree.
On the Pacific coast where the eclipse was about 15% total conditions
on the 80 meter band were reported as normal.
On the 40-meter band skip distance was such
that very few stations at distances less than 200 miles came through
at any time of the day. W1EKL could not be heard at W1EAO a distance
of 200 miles at the beginning of their schedule at 1400 G.C.T. (9
a.m. E.S.T.) with the aid of a frequency meter set on 7150 kc. After
listening 3 hours, W1ATW (220 miles) heard W1EKL for five minutes
at 1700 G.C.T., when he was lost and heard no more. In areas of
greater than 75% totality what few stations that were heard at distances
up to about 200 miles fell out completely near the maximum of the
In Fig. 3 is shown results obtained in the range
of 200 to 1000 miles for various degrees of eclipse. These curves
are composite averaged results from a great many observers and show
general tendencies omitting specific fading irregularities. Curve
A shows that near the path of totality signal strength was reduced,
the maximum reduction peaking approximately with totality. As indicated
in curve B for regions of 75 to 90% totality, signals at first increased
and then decreased rapidly at the maximum eclipse coverage. Reverse
effects were observed as the eclipse receded.
In regions of 50 to 75% eclipse, curve C, there was at first a slight
increase in signal strength as the eclipse came on. This was followed
by a dip to somewhat below normal and then a maximum increase was
observed lagging somewhat behind the maximum of the visible eclipse.
On the Pacific coast with 15% totality, curve D, signals gradually
increased with the partial eclipse and then slowly decreased again
Fig. 3 - 7000 kc. Band, 200 to 1000 Miles
A - 90 to 100%
B - 75 to 90% totality.
C - 50 to 75% totality.
D - 15% totality.
Distance reception of greater than 1000 miles
was also reported in the region of about 50% totality at various
times throughout the progress of the eclipse.
The distance of transmission on the 20-meter
band is such that widely different extent of eclipse was present
at the transmitter and receiver. In addition, contacts with European
stations were over a sunset area as well as the path of the eclipse.
No attempt has been made to differentiate between the results secured
depending upon whether the transmitter or receiver was at the location
of maximum eclipse effect. Undoubtedly a difference does exist,
but there was insufficient data to make comparisons.
reported on reception of high-powered commercial stations with varying
results. W1AFC at 99% totality reported no change in DGG on 22 meters
from 1830 to 2125 G.C.T. (1:30-4:25 p.m. E.S.T.). W1VF at 100% totality
reported a noticeable increase in signals from GID on 24 meters
during totality. In the region of 70% totality W9ABS kept watch
on WAZ, XDA, WQP, KKZ and HJO. From 1400 to 1800 G.C.T. the eastern
stations were R5-R7 with marked variations, west coast stations
R6 and steady. At 1800 the east coast stations rose to R8 very steady,
but at 1900 dropped out altogether. The west coast stations increased
to a very loud signal. From other sources we learn that the Canadian
Marconi Company found no definite change in 22- to 37-meter transatlantic
Fig. 4, curve A, shows the variation in reception of XDA (about
20% totality) on 20.7 meters by Charles E. Dewey, Jr., in Jefferson
City, Mo. (71% totality), at a distance of about 1400 miles. Between
these two points there was a time difference of about 20 minutes
in the phases of the eclipse. It would have been interesting if
these observations had been continued for at least an additional
hour, as in all probability another peak intensity would have been
Fig. 4 - 14,000 kc. Band
A - 71/20% totality, 1400 miles.
B - Night/95% totality, 4000 miles.
C - 96/50% totality,
D - 99/65% totality, 1230 miles.
E - 79% totality, 1 mile.
It should be pointed out that the commercial channels
are operated at a high power level and at a frequency that will
give reliable communication under the prevailing conditions. On
the other hand, amateur contacts on this band (and quite often in
other bands) are with comparatively low power, and more often than
not are in the "fringe" zone of possible contact. It is to be expected
then that small differences in the transmission path would produce
a much greater change on amateur transmissions than upon commercial
European observers of American amateur signals,
as well as observations from midatlantic ocean reported rapid irregular
fading together with mushiness of note caused by high-speed fading
during the period at and near totality. Curve B of Fig. 4 shows
reception of W2CJM by ON4AU, a distance of about 4000 miles from
darkness to a region of 95% totality and crossing the path of totality.
A general reduction in signal strength peaking with the eclipse
Curve C indicates composite results of observations
taken by G2JA at sea, 1560 miles east southeast of New York and
in a region of about 96% totality on the opposite side of the path
of totality from the United States. At this point sunset occurred
at about 2120 G.C.T. Stations received were at distances of 2000
to 3000 miles down to about 50% totality. This curve shows a regular
decrease in signal strength peaking with the visual eclipse. Results
toward the end of the period were partially obscured by twilight
effects, and this part of the curve is given as a dotted line.
In the United States, W1AZQ, in the path of totality, reported
European signals fading out and 6th district coming in at 2000 G.C.T.
During totality at 2030 G.C.T., only the 5th district could be heard
and with diminished strength. From 2105 to 2145 G.C.T. only 4th,
5th districts and Cuba were audible. At 2200 G.C.T. reception was
again near normal with the return of European signals until they
disappeared for the night at 2215 G.C.T.
Curve D shows reception
of W1HE (99% totality) by W9AOG (65% totality) at a distance of
1230 miles. Signals entirely disappeared for about one hour, the
center of this effect lagging about five minutes behind the visible
The results, curve E, obtained by W9RS and W9EGE
are quite interesting and show that even in the region of 79% totality
the reception of a one-watt oscillator over a distance of one mile
was considerably reduced.
On the broadcast band reports indicated that at distances less
than 100 miles night conditions of mushiness and fading were found
during the maximum of the eclipse. At distances of 200 miles near
the path of totality, no changes were observed. Reception of broadcast
stations from four to five hundred miles distant faded completely
or nearly out in various parts of the country, the maximum effect
peaking with the time of totality.
W1AFC found no change
in the intensity of FYL on 19,000 meters other than the normal daily
A great many amateurs
reported changes in QRN and were led to the belief that the eclipse
had left a high static level. A few reported no QRN for the entire
As mentioned earlier, during the period of the eclipse,
there were a great many areas of scattered thunderstorms throughout
the country, most of which occurred on the afternoon of eclipse
day. Analysis of the QRN reports show that without exception those
who reported bad QRN were near a local thunderstorm area, and those
who reported no QRN were at a considerable distance from one. Of
course the greater transmission range during the eclipse also carried
the static disturbances over greater distances. So it appears that
the eclipse can not be blamed for QRN conditions on August 31st.
Since the eclipse, the
results of some other observation parties have become available
and should be mentioned briefly in passing.
The Bureau of
Standards reported that measurements made near Washington, D.C.,
showed that the critical frequency for the E region of the Kennelly-Heavyside
Layer decreased about 1000 kc. during the eclipse, lagging behind
phases of the eclipse by approximately five minutes.
Observations made in Canada under the direction of Drs. Henderson
and Rose showed distinct losses in ionization of both reflecting
layers E and F regions during the period of the ideal eclipse and
no indications of a corpuscular eclipse.
Fig. 5 - Disturbance in F region of Kennelly-Heavyside Layer
during eclipse, 3942 and 4540kc.
Mimno, Pickard, and Wang gave a preliminary report to the Boston
Section of the I.R.E. on results of automatic photographic records
of echo lag behind ground signals. On 1640 kc. no echoes were observed
until ten minutes after totality (2040 G.C.T.), when the E layer
appeared at about 110 km. height. This persisted until 2110, when
it disappeared and the F layer came in at 250 km. and remained until
2130. No reflections were then observed until 2145 when the E layer
returned until 2200, when it vanished and was replaced by the F
layer which remained until sunset. On 3942 and 4542 kc. no E layer
reflections were observed, but there was an F layer disturbance
of double-humped character coinciding with the visible eclipse.
Because of its close resemblance to some of the amateur results
of reception, the curve showing this disturbance is reproduced in
And now after complete absence of any indication
of a corpuscular eclipse, there appears an article in the public
press stating that Dr. E.F W. Alexanderson of the General Electric,
by using a frequency of 8655 kc. between Schenectady, N.Y., and
Conway, N.H., had observed almost complete disappearance of signals
two hours previous to the optical eclipse, and attributes it to
a corpuscular eclipse. Although at this writing complete information
on his tests are not available, and full comment must be withheld,
it is difficult to accept his conclusions when it is remembered
that his tests were conducted in a region supposedly outside the
zone of a corpuscular eclipse.
The transmitter used at W1EKL, located at
Douglas Hill, ME, with Sid McCuskey, W8DRP, in charge.
stage used an 860 with 300 watts input. Although 3500 kc. operation
was first contemplated,
a frequency of 7150 kc. gave better signal
strength at Cleveland both day and night.
At the outset it was
stated that one of the questions which it was hoped to settle by
means of radio observations during the eclipse was whether the ionization
of the upper atmosphere was caused by ultra-violet radiation from
the sun or by neutral particles shot off at a much slower velocity.
Amateur transmission was most certainly effected during the
eclipse, the maximum effect in general coinciding with totality
of visible eclipse or lagging a few minutes behind it. In all cases
conditions approached those of night, the nearness of approach depending
upon the extent of the eclipse in the region. The return to normal
conditions seemed to be somewhat slower than the onset of the disturbance.
On 40 and 80 meters, double humped intensity curves were observed
similar in shape to the variation in the F layer height found by
the Harvard group of observers.
This would seem to prove
definitely that ultra-violet light, or some radiation travelling
with the speed of light, is mainly responsible for the ionization
of the upper atmosphere. The findings of scientific observers show
that there were changes in the E and F regions of the Kennelly-Heavyside
Layer coincident with the optical eclipse.
As regards a corpuscular
eclipse, and the acceptance of the opposing theory, very few observations
were taken by amateurs which could be used as a basis for a definite
conclusion. What observations were made over a sufficient length
of time and over the probable path of the corpuscular eclipse failed
to show any effect of such an eclipse, if there was one, on transmissions
in the amateur bands or on commercial frequencies close to amateur
On the other hand, if Dr. Alexanderson's results are accepted then
it would appear that the effect of the corpuscular eclipse was quite
small as compared to the optical eclipse and that the stream of
corpuscles or neutral electrons from the sun exert only a small
influence on the ionization of the upper atmosphere. So, for the
time being, at least, we still have the two theories with us.
Fig. 6 - The graphical recording of W1EKL's 7150 kc. signals
made at Case School shows a tremendous rise in signal strength
between first contact and totality, the recorder pen going
clear off the sheet at totality.
A few seconds later
the signal dropped down to the background level and was
inaudible for some 15 minutes. Then it gradually built up
and reached a second peak just before the moon's shadow
passed away, the pen again going off the sheet, with the
second peak lasting somewhat longer than the first. The
signals then gradually dropped to the normal level. The
eclipse was over.
Many amateurs expressed a regret that it would be a long time
before they could experience the enjoyment of noting the effects
of solar eclipses on radio transmission. The results reported here
show quite well that it is not necessary to be in the path of totality
to observe a "radio eclipse." Wherever the eclipse may be, the ever
resourceful amateur can select frequencies and stations upon which
he can make satisfactory and convincing observations. Let's continue
to make radio studies of coming eclipses.
1996 - 2018
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas
and reference material while performing my work as an RF system and circuit design engineer.
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