Accession Number : AD0726528

Title :   Frequency Variations of an Oblique 5 MHz Ionospheric Transmission.

Descriptive Note : Environmental research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Toman,Kurt

Report Date : 28 APR 1971

Pagination or Media Count : 18

Abstract : The 5-MHz WWV-transmission originating on the east coast of the United States at Beltsville, Maryland was received 604 km from the transmitter at Air Force Cambridge Research Laboratories, Bedford, Massachusetts. At the receiving end narrow filters were employed to separate the carrier frequency from the upper-side-band frequencies. The 5 MHz carrier frequency was heterodyned to 500 kHz and compared with a 500 kHz reference signal of an oscillator whose frequency stability was about 1 part in 10 to the 9th power. The diurnal frequency variation of the 5 MHz ionospheric signal was obtained for days selected from the year 1965. Optimum frequency stability was observed near noon. For 24 March 1965 the diurnal behavior of the 600 Hz modulation phase was obtained. Virtual height data from an ionosonde station located near the midpoint of the path were compared with Doppler frequency variations. (Author)

Descriptors :   (*RADIO WAVES, *IONOSPHERIC PROPAGATION), DIURNAL VARIATIONS, FREQUENCY MODULATION, PHASE MODULATION, DOPPLER EFFECT, HIGH FREQUENCY, RADIO INTERFERENCE, ATMOSPHERIC SOUNDING, IONOSPHERIC DISTURBANCES

Subject Categories : Radiofrequency Wave Propagation
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE