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capability of telecon between Parry Island and Los Alamos, New Mexico.
By utilizing re~encryption off-line and a TWX circuit, this second telecon
capability was extended to Livermore, Calif. These circuits, which were
cleared for Top Se@ret RD, proved especially useful during the months of
April and May, 1956, and relieved. an overloaded unclassified telephone net.
*Operation Redwing again pointed out the need for increasing the telephone plant at Parry Island. The presently installed 270-line manual switchboard is entirely inadequate to meet the needs of JTF 7. One hundred and
twelve main lines were allocated this task group at Parry Island. In order
to meet requirements of users, it was necessary to assign as many as five
extensions on numerous main lines, The Parry Island-Los Alamos unclassified telephone circuit voice quality was so poor that it received almost no
use during the operation.
It developed that radio silence was required in the Eniwetok Atoll area
on all frequencies below 200 Mc, in order that certain scientific projects
could be performed. The J-5 Section of Headquarters JTF 7 provided excellent service in locating and, by judicious reallocation of frequencies,
eliminating objectionable interference.
EG&G performed a study of fre-
quencies in the 150 to 160 Mc band and, as a result of this study, submitted
recommended frequencies for TG 7.1 scientific voice nets. It is interesting
to note that mutual interference between frequencies in this band was nonexistent. Although many more frequencies were used during Redwing than
in previous operations, radio interference showed a marked decline.
There were made available to TG 7.1 for Operation Redwing two of
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the latest type ciphony equipment held by the National Security Agency,
namely the AFSAY D-806-A and D-808-A. Owing to poor voice quality of
the D-806-A, this equipment was used for approximately 57 min-during a
two-month period. As a, result, the D-806-A was released by TG 7.1 on
June 13, 1956. The D-808-A, a laboratory model, proved a most acceptable
unit, During the last week of May and first week of June, tests were conducted which proved that the D-808-A could be used with the VHF interatoll
telephone and teletype circuit without sacrifice of channels in use, The
D-808-A net was then changed to provide sets at Parry Island, Enyu Island,
and USS Estes. Remotes were installed at ground stations and eventually
all three locations were netted. This circuit proved most reliable, and provided a clear net, secured for Secret RD, so essential to operations of this
type.
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The voice count-down for each event was broadcast on 245.0 Me,
168.975 Mc, and 154.47 Mc. The requirement for 245.0 Mc broadcast was
dictated by the conversion of all aircraft to UHF communication equipment.
CTG 7.3 required a simultaneous voice count-down on 168.975 Mc. Scientific
stations used receivers from previous operations crystallized on 154.47 Mc.
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