Allyn@uunet.UU.NET (04/12/90)
From: <ames!ames!claris!portal!cup.portal.com!Allyn@uunet.UU.NET> (re: the use of radio communications buoys to communicate with submerged subs) Navy subs are equipped with special communications buoys that can be deployed while the sub is submerged. The tricky part is how does the crew know when to deploy the buoy? (Can't have the buoy deployed all the time -- right?) This is where the Navy's Very Low Frequency (VLF) communications system comes into play. VLF waves can propagate through water so the subs can receive these transmissio ns while submerged. However, because of the wavelength, the data transmission rate is very slow (a 3 character SLOW morse transmission takes about 15 minutes to transmit, so the story goes) so the VLF system can't be used for detailed transmissions. So they way it works is thathe VLF system is used as a kind of paging system. When a sub receives their call on the VLF they know that, depending on orders, it may be time to deploy the buoy... ...or something like that...(-; Allyn Lai allyn@cup.portal.com