144 ASPECTS OF COMMUNICATIONS 



according to the listeners in the habitat, all transmission from the swimmer was garbled and 

 unintelligible. On day 10 a different swimmer unit was tried with another aquanaut, but again, 

 the mask gas loss occurred and the transmission was completely garbled. After this, no further 

 attempts were made with the Aquasonic. 



The wire intercoms were tested during Team I's dive. The transmission was completely 

 garbled and unintelligible. The same type intercom had been tested at 10 ft at the U.S. Navy 

 Mine Defense Laboratory, with very good results. 



SWIMMER TO SWIMMER 



The only type of swimmer to swimmer communication used with any degree of success was 

 the standard hand signals which have been used by Navy divers for many years. Development 

 of the sonic system discussed in the previous paragraph will add immeasurably to the ability 

 of divers to coordinate their underwater work. 



SUPPORT VESSEL TO SHORE 



Several communication links were available through the benthic laboratory. These included: 



Benthic link 1 - Two-way equipment and capability identical to that described in benthic 

 link 2. 



Benthic links 9, 10 - Two additional telephone handsets and amplifiers for two-way com- 

 munications to benthic control from the support vessel. 



None of the above three links were ever connected or used at the staging vessel end, be- 

 cause of an underwater telephone cable which was laid furnishing four telephone lines to the 

 staging vessel prior to the installation of the benthic laboratory. Three of these lines were 

 commercial telephones connected directly to the Pacific Telephone system, while the fourth 

 was a magneto type two-terminal circuit ("battle" phone) connected directly from shore control 

 to the support vessel. 



One HF, three UHF, and five VHF channels of communications installed aboard the support 

 vessel provided radio communications for the administrative and logistic functions of the oper- 

 ations. With these channels, communications were provided for the various support craft, 

 Scripps Institution of Oceanography, Mission Bay Aquatic Control Center, and various portable 

 and mobile units in the area. Through an unattended relay station on San Clemente Island, the 

 range of the radio communications was extended to include Long Beach and Pasadena. 



MISCELLANEOUS COMMUNICATIONS SYSTEMS 



PTC voice communications - The PTC used two systems of communication. The primary 

 system was an open microphone in the PTC to an intercom amplifier on the support vessel. 

 An Aquasonic system was used as a backup, but proved unsatisfactory. 



Support vessel interior voice communications - A 12-channel interior communication sys- 

 tem was installed on the support vessel connecting all primary and normally manned operating 

 stations. In addition, an intercom voice communication system from the outside DDC control 

 area to the interior of the DDC chamber was used with adequate results. Inasmuch as it was 

 vital that the atmosphere van personnel be cognizant of the physical condition of the subjects 

 during decompression, a slave station of the DDC intercom was set up in the Atmosphere Con- 

 trol Center. 



Benthic and Sealab Television - The TV system for benthic and Sealab used standard 525- 

 line interlace scan frequencies. Video transmission was accomplished using five amplitude- 

 modulated carriers on frequencies of 51, 60, 69, 78, and 87 MHz. 



