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Letter: Sporadic E Affects TV Signals, Too

A reader recalls E-Skip causing interference on analog TV channel 2

In this letter to the editor, the author responds to the story “Radio Magic on a Cold Winter’s Night.” Radio World welcomes letters to the editor on this or any story. Email radioworld@futurenet.com.


Regarding your excellent article on Sporadic E propagation and FM DXing, great reporting!  Of course, Sporadic E also impacts over-the-air TV signals. The following chart is kept in our company’s frequency and spectral lab as a reminder of this curious mode of propagation:

Bob Gonsett shared with Radio World a chart of the percentage of days with Es into FM above 88 MHz, 1980—1990.
Bob Gonsett shared with Radio World a chart of the percentage of days with Es into FM above 88 MHz, 1980—1990.

I’ve given talks on sporadic E and meteor scatter to local ham clubs in years and decades past and have played tape recordings of the signals received. It is my understanding that Sporadic E impacted TV Channel 2 to such a large degree in the NTSC days that CBS frequency locked their CH-2 owned-and-operated stations to WWVB in order to reduce mutual interference effects.

One such example was KCBS(TV), channel 2, Los Angeles. Our lab checked KCBS at monthly intervals to make sure it was indeed locked to WWVB. Because of KCBS’ wide reach in so. Cal., 55.250000 MHz (their visual carrier frequency) was often used as a secondary “frequency standard” to check the accuracy of communications service monitors in the field.

Again, great reporting!

— Robert Gonsett, Communications General Corporation, Fallbrook, Calif.

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