What question did this study set out to answer?

To measure and characterize instantaneous frequency shifts in 20-MHz standard radio transmissions propagated across a 4,000-km path under varying geomagnetic and ionospheric conditions.

October 1, 1960Journal of Geophysical Research Atmospheres

Continuous recordings of the frequency variation of the WWV-20 signal after propagation over a 4000-km path

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Authors

RFR. C. FenwickMott MacDonald (United Kingdom)OVOswald Garrison VillardSRI International

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Implication

Observational study reveals diurnal and geomagnetic frequency shifts in WWV-20 transmissions, indicating ionospheric layer movements and magnetic disturbances alter long-distance signal stability.

Key Points

To measure and characterize instantaneous frequency shifts in 20-MHz standard radio transmissions propagated across a 4,000-km path under varying geomagnetic and ionospheric conditions.
Continuously recorded the instantaneous frequency of the primary received WWV-20 signal over 30 days during spring 1960 at a receiving station in Palo Alto, California.
Evaluated frequency variations during quiet and magnetically disturbed periods, comparing one-hop versus two-hop propagation modes and correlating shifts with local total magnetic field measurements.
Normal days displayed systematic diurnal shifts of roughly 1 part in 10^7, with frequencies rising above normal in the morning and falling below normal at night.
Magnetically disturbed days produced maximum frequency shifts reaching approximately 3 parts in 10^7, with instantaneous frequency fluctuations correlating with local geomagnetic field variations.
One-hop propagation produced considerably smaller frequency deviations than two-hop propagation, while transient upward shifts up to 3 cps (1.5 parts in 10^7) occurred over 1 to several minutes due to descending ionization clouds.

Cite This Study

Fenwick et al. (1960) studied this question.

synapsesocial.com/papers/6a8828489fc8a8114e4a66ff https://doi.org/10.1029/jz065i010p03249

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Implication

Observational study reveals diurnal and geomagnetic frequency shifts in WWV-20 transmissions, indicating ionospheric layer movements and magnetic disturbances alter long-distance signal stability.

Continuous recordings of the frequency variation of the WWV-20 signal after propagation over a 4000-km path

Discussion

Member takes

Implication

Key Points

Cite This Study

Continuous recordings of the frequency variation of the WWV-20 signal after propagation over a 4000-km path

Discussion

Member takes

Implication

Key Points

Cite This Study

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