ON ay, - With the decision not to reestablish shore bases tn the Bikini area after Shrimp, the following changes in communications were made: 1. Communications Headquarters was shifted afloat to the Estes. 2, TG 7.1 RATT circuit was discontinued, 3. HF voice net was terminated aboard the USS Estes by remoting the circuit, using an AN/TRClink from Enyu to the ship. 4, An additional VHF voice link was installed on five afloat stations to provide Rad-Safe with necessary communications. 5. Stations were added or removed from the existing seven TG 7.1 VHF radio nets as the * work load dictated. Communications to TG 7.1 projects located at Okinawa, Guam, Ponape, and Rongerik were handled by using existing facilities at those stations. The CP _ was located in Station 70 on Enyu and was manned through shot time by CTU-6 andthe Firing Party, and TG 7.1 Headquarters was located in Flag Operations of. nets. Messages of classification Secret and below to CTG 7.1 (Admin) at Eniwetok and all off- mow ondary Moturola net for unclassified messages. CTG 7.1 was in communication with all Task Units located aboard ships in the im.mediate area by three separate commercial radio voice oo. aboard the Estes. These stations were linked by two voice circuits, a primary net using Ciphony equipment that was cleared for classified traffic including Secret Restricted Data and a sec- site stations were transmitted and received over the Estes “On Line” RATT circuit with Sam- son (synchronous mixer) through the relay-crypto center at Eniwetok. All Top Secret and Resivicted [sta traffic was enciphered “Off Line.” The voice time broadcast was transmitted rianually over the Baker channel and the TG 7.1 Admin net on the Estes from —3 to --1 hr, at vi se & @. Cem web rn which time a tape recording synchronized with the sequence timer automatically took over at tation 70 on Enyu. —. The CP and TG 7.1 Headquarters! . ‘were located in Flag Operations aboard the USS Estes. This CP functioned by employing three 250-watt Motorola radio links to start the timing signals and the sequence timer, and to actuate the emergency stop in Station 70 on Enyu. The voice t!...e broadcast was transmitted in the same manner with the exc eption that only the last 15 min were tape re- corded and automatically transmitted f f rom Station 70 on Enyu. The CPi_ was located in Building 311 on Parry, with TG 7.1 Head- quarters in Building 209 on the same island, These stations were in contact by a telephone “Bot Line,” normal telephone, and two VHF voice radio nets. CTG 7.1 was in communication with the Estes, the Air Control ship, on station 20 miles off Parry, by AN: TRC radio through the Perry switchboard. Messages, Secret and below, to other elements of TG 7.1 in the Bikini area and ali off-site stations were transmitted and received over the Parry Task Force “On thy Line” RATT circuit with Samson (synchronous mixer) through the relay-crypto center at Eniwetok, All Top Secret and Restricted Data traffic was enciphered “Off Line.” The voice time broadcast was transmitted manually from the CP over the Baker and TG 7.1 Admin nets from —3 hr through zero with an automatic tone signal replacing the Rack for the last 15 min, 3.13.1 Communications by Electrical and Electronic Equipment Various types of electrical and electronic communications equipment were used to provide TG 7.1 with the means to maintain close liaison between the separated projects in the Forward Area. These types included an intercommunications net between cffices, telephones, six separate VHF radio circuits, an HF voice radio circuit, and a radio teletype circuit. The radio teletype circuit was installed and maintained by EG&G and operated, with the exception of the Crypto-Samson (synchronous mixers) processing which was the respcnsibility of CITF SEVEN, in conjunction with the Mail and Records offices. The transmitting and receiving stations for this net were located at Parry, Enyu, and Eninman and were in operation normally seven days a week from 0730 to 2230 hours and on a 24-hr day at the ciscretion of CTG 7.1. This circuit was cleared for messages up to and including Secret Restricted Data and was available to all 52