planes flying overhead and analog signal

[skippercollector]

The house I grew up in was on the western side of a hill just west of Cincinnati. (I saw sunsets whenever it wasn't cloudy, which was nice.) We didn't have an antenna, except for the ones on the televisions themselves.
In the 70s and 80s, we watched the analog signals from Cincinnati for the following:
Channel 5, WLWT, NBC
Channel 9, WCPO, then CBS
Channel 12, WKRC, then ABC
Channel 14, WPTO (Oxford), PBS
Channel 19, WXIX, then an independent station (now Fox)
Channel 48, WCET, PBS
Channel 54, WCVN (Covington), PBS
Channel 64, WSTR, then an independent station (now CW)

We could also watch, although they were grainy:
Channel 7, WHIO, CBS
Channel 16, WPTD, PBS
Channel 22, WKEF, ABC
Channel 45, WSTR, then an independent station (now Fox)

The one Dayton station we had difficulty receiving was Channel 2, WDTN, NBC. It was always far grainier than the other stations. Ironically, it was the Dayton station that The Cincinnati Enquirer Sunday TV booklet promoted first. For much of the 1970s, The Enquirer never even listed what was on Channel 22, although that signal was the best of all!
However, I noticed that if I were trying to watch Channel 2, and an airplane flew overhead, the picture came in clearer for a few moments! Why was that? Was the signal bouncing off the bottom of the airplane?

 

[KeithE4]

The one Dayton station we had difficulty receiving was Channel 2, WDTN, NBC. It was always far grainier than the other stations. Ironically, it was the Dayton station that The Cincinnati Enquirer Sunday TV booklet promoted first. For much of the 1970s, The Enquirer never even listed what was on Channel 22, although that signal was the best of all!
However, I noticed that if I were trying to watch Channel 2, and an airplane flew overhead, the picture came in clearer for a few moments! Why was that? Was the signal bouncing off the bottom of the airplane?

Definitely. Planes flying overhead could also cause ghosts on some analog stations, but in some cases would actually enhance a signal briefly. In the DTV world, the station just goes away due to phasing issues caused by the multipath.

 

[KML0224]

Did the same phenomenon cause flutter on FM as well?

 

[bpatrick]

Channel 2 is most susceptible to interference; it's why
stations avoided it in picking their digital channels.

We used to live near Tampa International Airport, and
every time a plane would fly near our house we'd get
interference with the sound on WTVT/13; a buzzing sound would come
in, especially when a Vidifont graphic (remember those in
the '70s) was on-screen. My mom called WTVT about this, their
response was, "We're not having any problem here (at the station)."
That, of course, did not satisfy her but it's something we had to
learn to live with.

 

[tvnut]

Did the same phenomenon cause flutter on FM as well?

It does. And sometimes, it enhances or makes possible brief long-distance reception of a station when the plane is equidistant between your location and the transmitter. If it's a regular route with a lot of flights, that can go on all day, a few minutes at a time.