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Reception in space

B

bobdavcav

Hi all,
Let's go out of this world for a bit. Does anyone know, or at least have any theories about, what AM/FM reception would be like in space? I would think one of the following would be true:
1. You would get a jumble of everything, making any one station unlistenable.
2. You would get one station at a time, but listening would be impractical, especially on FM, because your position relating to a single point on Earth is changing so fast. It takes the ISS 90 minutes to orbit the earth, so that doesn't give much time to listen to one single station, though if you could stop moving relative to the earth, you would be able to pull in one station loud and clear.
3. You wouldn't be able to get anything. I would think this would be more likely on AM due to solar interference. Any other theories?
 
From the ISS? A mumble-jumble of stations 24/7. One hour it's Hawaii and California, the next it's Queensland.
At my location I get aircraft scatter all afternoon and evening from the contrails of planes at 35,000 feet and higher. Some pass within 2 miles of city limit. The max distance seems to be 285 miles or so.
 
Doesn't the ionosphere stop AM radio signals from travelling any further? And FM being line of sight, I have doubts about outer space reception.
 
I think number 1. Too much interference and moving too fast. A lot of places in New Jersey between New York City and Philadelphia, tuning to 100.3 or 101.1 and moving 50 mph, it's hard to comprehend thats how bad the interference is. These are just two stations and a much less speed and ground level.
 
Has anyone here listened to a Walkman while on a plane? It's an interesting experience. The FM signals can reach through the plane's metal but not easily. You usually get noise on each channel. But sometimes a station will come in and stay with you for a while, even if you aren't passing directly overhead. I remember one flight from the NYC area to the West Coast. As we passed over Ohio and Indiana, I heard several Canadian stations. I heard ads for Tim Horton and Canadian Tire, even if I wasn't sure of the station.

But of course, I wasn't in space, just about 30 to 40,000 feet above the ground.
 
Not likely you'd have a shot at AM in space. FM, maybe you have a shot at the horizontal polarization of a station way over on the horizon. If you had the vertical polarized signal you'd have to be right above the city and only get the signal for a short time.

The premise of the movie "Contact" is based on the aliens picking up German TV signals of the 1936 Olympics, never mind they were low power and barely reached across Berlin. Hey, it's a movie.
 
Trying not to get too technical: A lot of class C or B FMs get to a lot of gain from their antenna. They do this by "redirecting" RF power from above the horizon down to usable angles. In theory you might not pick up a Class C or B FM with a 5 times or more power gain directly over tower.

IMHO In weird way at over 50 k + feet or more you might pick up a lower power station with a one bay antenna. A geosynchronous satellite would be easier to capture signals because you don't "move" relative to the stations.
 
Theory?

Happens all the time - 2m/70cm amateur operation has been happening for years.

More here: Contact the ISS
 
I spent years trying to improve the signal in cars and homes. I really never gave much thought about space. I'm not being negative but I just try to speak from experience. I do remember the moon missions had those huge antennas scattered around the globe.

If you want to go to a strange place go, go to Green Bank WV. The biggest moveable antenna I ever seen. It also had a negative effect on WELK when they started in the 1980s.
 
Gregg. said:
Has anyone here listened to a Walkman while on a plane? It's an interesting experience. The FM signals can reach through the plane's metal but not easily. You usually get noise on each channel. But sometimes a station will come in and stay with you for a while, even if you aren't passing directly overhead. I remember one flight from the NYC area to the West Coast. As we passed over Ohio and Indiana, I heard several Canadian stations. I heard ads for Tim Horton and Canadian Tire, even if I wasn't sure of the station.

But of course, I wasn't in space, just about 30 to 40,000 feet above the ground.
Click to expand...
That's actually what got me thinking about this topic. A friend and I were talking about exactly what you are, and that got me wondering about space. I've never actually listened to FM on a plane, I might have to try that next time I fly. That could be this summer.
 
bobdavcav said:
I've never actually listened to FM on a plane, I might have to try that next time I fly. That could be this summer.
Click to expand...
I have, once, a long time ago.
Be prepared for a mess of FM stations, stations overlapping each other and changing frequently. Can't recall how AM sounded, but don't think it came in much.
 
It’s easy to get FM stations on a plane. AM not at all in my experience. Years ago I regularly scanned and sampled FM stations in flight. It was fun. Today, operating a radio (transmitter or receiver) is technically not allowed on commercial flights.
 
Gregg. said:
Has anyone here listened to a Walkman while on a plane? It's an interesting experience. The FM signals can reach through the plane's metal but not easily. You usually get noise on each channel. But sometimes a station will come in and stay with you for a while, even if you aren't passing directly overhead. I remember one flight from the NYC area to the West Coast. As we passed over Ohio and Indiana, I heard several Canadian stations. I heard ads for Tim Horton and Canadian Tire, even if I wasn't sure of the station.

But of course, I wasn't in space, just about 30 to 40,000 feet above the ground.
Click to expand...
I did that on a few flights and had the same experience: noise on all FM frequencies with stations fading in and out usually within 5 minutes. The radio I was using had no AM capability, but I'd imagine nothing would be audible given the altitude of the plane, its metal frame and all the electronic/mechanical noise a jetliner generates.
 
DrJerry said:
It’s easy to get FM stations on a plane. AM not at all in my experience. Years ago I regularly scanned and sampled FM stations in flight. It was fun. Today, operating a radio (transmitter or receiver) is technically not allowed on commercial flights.
Click to expand...
Hasn't that always been the case. I know it was in 2002, when I brought a Walkman-type unit on board a Boston-to-Tucson flight (via DFW). I brought several cassettes with me and listened to them, then quietly switched to FM to see what I could hear there. No one hassled me at any point. Do flight attendants now order passengers to put any such device away if they see one in use?
 
I don’t think radios were specifically disallowed back in the 80s or even 90s. Might have been part of post 9/11 restrictions. If you had a large/obvious radio, they would probably tell you no. But assuming a small device and headphones, they wouldn’t likely notice. I also doubt that a majority of people bother to put their phone in airplane mode…
 
DrJerry said:
I don’t think radios were specifically disallowed back in the 80s or even 90s. Might have been part of post 9/11 restrictions. If you had a large/obvious radio, they would probably tell you no. But assuming a small device and headphones, they wouldn’t likely notice. I also doubt that a majority of people bother to put their phone in airplane mode…
Click to expand...
It was after 9-11.
I kept it hidden, the headphones looked like any other media player. Need to do that again with a radio.
 
Maybe about 15 years ago, I remember flight attendants would ask you not to listen to the radio if they saw you had a Walkman. It had to do with that unusual aspect of radio listening that few of us even knew about. Tuning in a station at a certain spot on the dial on one radio could have an affect on reception on a nearby radio. I vaguely remember an experiment I saw once and tried myself, tuning one AM radio to 1400 kHz and another to 700 kHz... or something like that. But the radios were only a few feet from each other and this was AM, not FM.

I believe that concern was cancelled years ago. The radios used by pilots in the air today have no frequency relationship to the AM or FM radio you might have in your Walkman. I think I have that right.

Of course, hardly anybody listens to a Walkman or other similar radio these days. So I don't think flight attendants would even know about this rule anymore, if it still exists.
 
If you had a radio lingering a few hundred feet above the Empire State Buildings antenna, are you getting nothing from the NYC stations? Are they overloading? or is it just a lot weaker?
 
Most airlines do not allow radio usage on the flight.
The exception in the last 10 years has been Delta. The 'Sky' magazine they used to have explicitly says that AM/FM radios were allowed in-flight as soon as they reached a certain elevation.
Based on the aircraft scatter I constantly get, and that the aircraft attenuates some of the signals, I would assume that a lot of the same stations I pick up on scatter (and several Boise FMs) would be audible at 35K feet over my location, and maybe a few more. I constantly get several Pocatello, Twin Falls, Tri-Cities, Spokane, Bend, and Yakima FMs on the 4-element.
Also, based on YouTube videos I have seen, the limit of reception would be roughly 300 miles (maybe 350+ in isolated western US areas). They overlap a lot more on the east coast with the saturation of markets, often several deep. You could have the same 100KW station for a half-hour or longer over Utah or Wyoming.
 
It was amazing hearing the stations over Indiana and other states. Would've listened longer, but was trying to listen incognito.
 
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