DocumentCode :
1046405
Title :
Frequency variations due to over-the-horizon tropospheric propagation
Author :
Chisholm, J.H. ; Goodman, S.J. ; Kennedy, J.M. ; Lambert, L.B. ; Rainville, L.P. ; Roche, J.F.
Author_Institution :
Massachusetts Institute of Technology, Lexington, MA, USA
Volume :
9
Issue :
4
fYear :
1961
fDate :
7/1/1961 12:00:00 AM
Firstpage :
384
Lastpage :
389
Abstract :
An experiment was performed over a 161-mile path between Alpine, N. J., and Round Hill, Mass., to determine the frequency fluctuations produced by the propagation mechanism on a highly stable signal in an over-the-horizon tropospheric circuit. A signal at 388.0 Mc was transmitted from Alpine using a 10-kw transmitter and a 12\\deg beamwidth antenna. These transmissions were received at Round Hill with a 5\\deg beamwidth antenna and heterodyned to 416.7 Mc using a highly stable local oscillator and retransmitted to Alpine. Using coherent reception techniques, the retransmitted signal was received at Alpine and heterodyned with the signal originally transmitted. The difference frequency was fed to a bank of narrow-bandwidth crystal filters. An analysis of the data obtained from these filters indicated that the standard deviation of the frequency fluctuations of the signal was approximately 0.6 cps when CW transmission was employed. An additional feature of the experiment was an attempt to measure the variations of the propagation path length as a function of time. It appears that the standard deviation of the path length variations was less than 55 meters when the average path length in frac{1}{6} -second intervals was measured.
Keywords :
Tropospheric radio propagation; UHF radio propagation meteorological factors; Antennas and propagation; Circuits; Filters; Fluctuations; Frequency; Length measurement; Local oscillators; Receiving antennas; Transmitters; Transmitting antennas;
fLanguage :
English
Journal_Title :
Antennas and Propagation, IRE Transactions on
Publisher :
ieee
ISSN :
0096-1973
Type :
jour
DOI :
10.1109/TAP.1961.1145017
Filename :
1145017
Link To Document :
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