ELF Propagation; User's Handbook, DNA-EH-88-08-G HTI-SDR-88-368 Version 1.0 for the IBM PC

San Diego, CA and Washington, DC: Horizons Technology Inc. for Defense Nuclear Agency, 1988. Presumed First Edition, First printing [Version 1.0 stated]. Spiral bound. Very good. The format is approximately 6.25 inches by 8.5 inches. Various paginations (76 pages per Standard Form 298). Illustrations. Tables, Appendices. Cited References. Additional References. RARE surviving copy. This was prepared for the Defense Nuclear Agency as part of their Electronic Handbook Series. Extremely low frequency (ELF) is the ITU designation for electromagnetic radiation (radio waves) with frequencies from 3 to 30 Hz, and corresponding wavelengths of 100,000 to 10,000 kilometers, respectively. In atmospheric science, an alternative definition is usually given, from 3 Hz to 3 kHz. In the related magnetosphere science, the lower frequency electromagnetic oscillations (pulsations occurring below ~3 Hz) are considered to lie in the ULF range, which is thus also defined differently from the ITU radio bands. ELF radio waves are generated by lightning and natural disturbances in Earth's magnetic field, so they are a subject of research by atmospheric scientists. Because of the difficulty of building antennas that can radiate such long waves, ELF frequencies have been used in only a very few human-made communication systems. ELF waves can penetrate seawater, which makes them useful in communication with submarines. The United States, Russia, India, and China are the only countries known to have constructed these ELF communication facilities. The U.S. facilities were used between 1985 and 2004 but are now decommissioned. The ELF Propagation program is intended to provide the user with a semi-quantitative appreciation of the effect of a widespread ("uniform spread debris") nuclear environment on Extremely Low Frequency (ELF) signal strength at a signal strength at a specified receiver location. Inputs include the fission debris yield and the time after burst the date, time and frequency of the transmission, the dipole moment of the transmitter,and the latitude and longitude of the receiver. The transmitter is, additionally, assumed to be located at the U.S. Navy Wisconsin Test Facility, nominally at 40 degrees north latitude and 91 degress west longitude; the receiver can be anywhere. Outputs are the vertical electric field at the receiver under ambient conditions, the vertical electric field at the receiver under nuclear-disturbed conditions, the difference in field strength, and the phase difference in the two signals (in degrees or radians). Optional outputs are the attenuation rate, the phase velocity and the vertical excitation factor as a function of distance from the transmitter. Results may be saved to two output files containing all inputs,outputs, and listing of the ionospheric profiles used during a particular run.