By the end of World War II, Naval authorities had already begun drawing up their research agendas. It was they who, through oceanic testing of nuclear warheads, were some of the very first military groups to observe and recognize the implications in the EMP effects. Appreciating the need for maintaining secure-communications of an unjammable kind. Naval authority was quick to recognize that VLF, however deep, might not thoroughly serve the new world situation. The nuclear weaponry, whose unexpected appearance rocked the entire military community, exerted its lasting demands on their research expertise. This technology-demanding shockwave lasted long after the nuclear shots had long dissipated.
NRL directed a wide variety of experimental tests on much deeper VLF than had ever been conducted on such a grand scale. They already knew that the deeper the VLF signal frequency, the less rufQed signal continuity would be. Indeed, it was found that deeper than VLF waves could sustain EMP phenomena with no blackout vulnerability whatsoever. In this light, the numerous drawbacks of deepest VLF was not now objectionable. If radiowave systems were going to be relied upon at all, then these were the very epitome of reliance. Moving to even lower frequencies was going to place heavier requirements on the engineers, to build the monstrous stations, and on operators, who would now have to slow down their signalling to inhuman tempi. Indeed, automatic digital systems would be required to tap out the encrypted messages which had been loaded into their new electronic memory banks. Deepest VLF would indeed be very slow, a laborious means for exchanging large volumes of critical information. Nevertheless, here was the only alternative then available to the military community. In truth, during territorial emergency, only
Deepest VLF would maintain secure-communications continuity.
Some objected that such signal energy demonstrated an alarming ability to permeate even “enemy” ground. Once launched from their geological “chutes”, deepest VLF signals spread out rapidly across the surface of the earth. Entering its meandering routes, such VLF signals could easily be intercepted anywhere, by anyone. While this fact was not problematic during the early years of ground conduction VLF systems before World War I, strict techniques for the preservation of military secrecy would now be an absolute. Furthermore, such energies could not be served by the military encryption systems which served radiotelephonic channels. New digital code encryption techniques would now be developed and implemented. Deepest VLF wave transmission was the available reliable communications channel.
An objection to the establishment of these stations considered the that these easily discerned structures would be among the very first target-strike zones. The large fixed VLF installations were captives of their own monstrous size. RCA directed the construction of the 10 Megawatt Jim Creek Station, call letters NLK, in Oso, Washington. The Naval VLF station NAA is a 2 Megawatt station which operates at 14.8 Kilocycles. Comprising 26 towers, each an average of 900 feet height, NAA occupies a peninsula of 300 acres in Cutler, Maine. Military planners did not appreciate the fact that VLF stations such as this represented such easy wartime targets. VLF wave stations could be destroyed in a single blast For this reason, the mihtary devised an elaborate ground-based scheme to incorporate a great number of simultaneous triggered stations, a VLF Network. Operating in synchronous intermittent blasts, the VLF stations would be switched on and off by a central command control system. The possible destruction of any one such site would in no way deimage the integrity of the whole Network. No one site would carry <ill the information of a single transmission. In addition, VLF is virtually impossible to triangulate. The nature of the deep ground-hugging signal precludes any ordinary radio scanning means by which to ascertain the exact target location of any one such station. Therefore, unless espionage had provided very exact coordinates on these systems, there would be no possibility of their immediate destruction. In addition, these sites would be the most highly defended national zones in such an emergency.
A small amount of deep VLF energy was found to have an effective and remarkable long distance range. Ionospheric ceilings did not drastically distort deep VLF wave signals. Both NUCLEAR and RADAR EMP methods could scramble all electromagnetic wave channels for dangerously long time periods by disturbing the ionosphere directly, artificial chaotic conditions. All channels which relied on excessive skywave components were thus rendered useless by the method, a new breed of electronic push-button weaponry. But deep VLF wave channels were not nearly affected at all. This proved to be especially true with decreasing VLF frequency, an inference that at lowest frequencies, one might find a zero disturbance condition. Such a frequency band would then offer secure-communications continuity despite the disturbing detonation of hundreds of nuclear warheads. This observation prompted several new projects, the first practical necessity being to establish more resilient deep VLF wave stations.
The NRL began working closely with VLF experts to produce an ELF communications system which, relying on ground wave conduction, could not be disrupted by high altitude ElMP’s. Several preliminary tests were conducted with LORAN-C broadcasts to assess the power efficiencies of such a scheme. Naval VLF stations joined in several cooperatives, broadcasting and monitoring signals along sp>ecific pathways. Terrestrial magnetic variables were extremely responsive to EMP currents. Deep VLF wave correlated studies followed nearly perfect compass headings. Such channels were not completely impervious to space EMP effects. The last two nuclear space blasts of Project ARGUS proved the availability of ELF channels in catastrophic EMP. The direction was clear, the new quest was to devise an ELF communications system.
There was another purpose in these directions. The newly established nuclear submarine fleet had new and demanding requirements. The obvious need for complete secrecy in deep submarine communications brought about an amplified interest in ELF systems. Fleet balhstic missile submarines (POLARIS) necessarily remained submerged at very great depths for long time periods. Traditional surface communications modes were abandoned by these submarine nuclear armories, where such vulnerability would be negated by a new mode. It was well established that radiowaves were attenuated by seawater inversely as the frequency decreased. ELF ground conduction waves were found capable of reaching any required depth. Continually transmitting and receiving command base messages while completely submerged, POLARIS submarines could then engage enemy forces with previously unheard tactical efficiency. In addition to these low propagation losses, ELF signals demonstrated a remarkable resistance to natural and EMP disturbances. A project was initiated for the explicit construction of an EMP safe radiowave communications system in the Extra Low Frequency band of the wave radio spectrum.
World History
