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In addition to on-going radioastronomical observations, there have been several deliberate attempts to detect signals of extraterrestrial intelligent origin, all with negative results. In most cases, only a few select objects have been observed, at a few discrete frequencies using relatively wide bandwidths and at only moderate to low sensitivities. Although most laudable, these observations require enormous equivalent isotropic radiated power on the part of other civilizations to be detectable.
|
INVESTIGATOR |
OBSERVATORY |
DATE |
FREQUENCY OR WAVELENGTH |
TARGETS |
|
. | ||||
|
DRAKE |
N.R.A.O. |
1960 |
1,420 MHz |
EPSILON ERIDANI TAU CETI |
|
TROITSKY |
GORKY |
1968 |
21 AND 30 CM |
12 NEARBY SUNLIKE STARS |
|
VERSCHUUR |
N.R.A.O. |
1972 |
1,420 MHz |
10 NEARBY STARS |
|
TROITSKY |
EURASIAN NET-WORK, GORKY |
1972 TO PRESENT |
16, 30 AND 50 CM |
PULSED SIGNALS FROM ENTIRE SKY |
|
ZUCKERMAN, PALMER |
N.R.A.O. |
1972 TO PRESENT |
1,420 MHz |
~600 NEARBY SUN LIKE STARS |
|
KARDASHEV |
EURASIAN NETWORK, I C.R. |
1972 TO PRESENT |
SEVERAL |
PULSED SIGNALS FROM ENTIRE SKY |
|
BRIDLE, FELDMAN |
A.R.O. |
1974 TO PRESENT |
22.2 GHz |
SEVERAL NEARBY STARS |
|
DRAKE, SAGAN |
ARECIBO |
1975 (IN PROGRESS) |
1,420, 1,653, AND 2,380 MHz |
SEVERAL NEAR-BY GALAXIES |
|
DIXON |
O.S.U. |
1973 TO PRESENT |
1420 MHz |
AREA SEARCH |