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Apr 24, 2021 · When multiple different transmitters, perhaps at very different distances, are involved, it means that each transmitter arrives at the single receiver at the same power level, which optimises their signal to mutual interference ratio.
- Basic Radio Propagation
- F2 Skip
- E Skip
- Tropospheric Ducting
- Transequitorial
- Meteor
- Moon
- Aurora
- What About DTV?
At shortwave frequencies, distant propagation is much more common. Shortwaves travel via ground wave (short distance) and sky wave. However, parts of our atmosphere–particularly, the part about 25 to 250 miles overhead called the ionosphere–can bounce signals back to Earth (technically, the radio signals are refracted or bent; see image to the left...
The MUF isn’t the same everywhere on the Earth. You have to consider the MUF between two spots (say, Houston to Paris). Naturally, this changes based on the time of day and other factors like sunspots and other solar weather phenomena. You can see a near real time map of MUF for 1800 mile pathsonline. You’ll probably notice that the highest numbers...
Another part of the ionosphere is the E layer and it is subject to having sporadic ionization. These ionized areas will reflect radio signals up to 1,400 miles. Sporadic ion clouds in the E layer are measured using ionosondes, and you can find maps showing where these ion clouds are. E skip tends to come and go quickly, but can also be very strong....
Normally, TV signals don’t bounce off the atmosphere because the MUF is too low, but certain weather conditions (temperature, density, and humidity) will cause the troposphere (the lowest layer of the atmosphere) to refract it. When a temperature inversion occurs (warm air over cool air), the troposphere can form a duct that can transport signals o...
There is a special propagation mode that allows transmitters to hit receivers up to 5,000 miles away when the receiver is about the same distance from the equator as the transmitter (but on opposite sides of the equator). For example, television from Japan is sometimes received in Australia, thanks to transequitorial propagation. There are actually...
When there is a meteor shower, hams use special software to communicate with other hamsover long distances. This is often called Meteor scatter, but it actually relies on the ion clouds created in the E layer by the meteors. So from that perspective, this is the same as E skip, but generally of very short duration. The clouds generally only last fo...
Although you don’t bounce signals directly against meteors, you can bounce a signal against the moon. The moon is about 239,000 miles away so path losses are around 240 dB. That means you have to have pretty good antennas and receivers to even attempt picking up signals bounced off the moon. When there were fewer TV stations, it was slightly easier...
Another space phenomenon that can cause distance TV reception is an aurora. Solar flares (as well as other solar weather events) take about a day to reach Earth and can create an aurora. Depending on the characteristics of the event, there may be an aurora and that can cause part of the atmosphere to reflect radio waves. However, signals propagated...
Digital TV is subject to similar propagation effects. There are two problems. Today, you are more likely to have cable and less likely to have an external antenna well positioned for distance reception. The other problem is that the digital signals tend to degrade all at once. On an old analog signal you could squint and use the wet video processor...
Jan 2, 2020 · It happens when there’s a temperature inversion: Instead of air steadily getting cooler when moving from the earth and through the troposphere, cold air gets trapped in a layer. The cold air layer can be at the surface, or between a warm layer on the earth and another warm layer close above it.
indieNET, an arrangement CHCH (in Ontario), CHEK (in British Columbia), & CJON (in Newfoundland and Labrador), three independent broadcasters, have with Yes TV to sub-license some of Yes TV's programming
What's on TV tonight including Free TV, Shaw, Rogers, Bell TV and Cogeco. Search the Canadian TV Listings Guide by time or by TV channel and find your favorite shows.
Overview. Childhood friends Mamoru Toyama, Hiroki Tanaka, and Kotone Imabata begin their activities as the three-person new YouTuber group channel “LifeLive”. The three began steadily posting various videos under the motto, “Be Yourself!
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