of Contents]These articles are scanned and OCRed from old editions of the
ARRL's QST magazine. Here is a list of the
QST articles I have already posted. All copyrights (if any) are hereby acknowledged.
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 the
of the E and F regions, both of which
were proposed in 1902 (yes, the Heaviside of
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.
Amateur Observations During the Total
Eclipse of the Sun
By R.W. Woodward, W1EAO
EQUIPMENT USED AT THE CASE SCHOOL OF APPLIED SCIENCE, CLEVELAND,
FOR GRAPHICAL RECORDING OF THE SIGNALS OF W1EKL
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
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 Layers.
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.
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.
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
The following contributed reports on their results
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.
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
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.
Fig. 1 - 3500-kc. Band, 90 to 100% Totality
A - Less than
B - 50 to 200 miles.
C - 200 to 500 miles.
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.
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.
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, 2134 G.C.T.
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.General Conditions
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.
From these 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
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.80-Meter Band
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.
The 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
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 irregularity.
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
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 the eclipse.
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 eclipse.
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.
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.
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 to normal.
reception of greater than 1000 miles was also reported in the region
of about 50% totality at various times throughout the progress of the
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.
Many 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 reception.
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.
- 79% totality, 1 mile.
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 found.
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 channels.
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 is noted.
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.
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
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 eclipse.
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. Longer Waves
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 change.
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 period.
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.
Fig. 5 - Disturbance in F region of Kennelly-Heavyside Layer
during eclipse, 3942 and 4540kc.
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.
Messrs. Kenrick, 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 Fig. 5.
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.
The output 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.
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.
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 assignments.
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.
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.
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.