Hi all,
Can someone explain to me why radio reception is usually better at night.
Also, when I'm tuned into a base station like a trunking system, why does it fade in and out with static all the time, if neither the base or my scanner are moving? This occurs after sunrise...
Cheers
Numloxx
Fading in and out
Moderator: yorky
Re: Fading in and out
[quote="numloxx"]Hi all,
Can someone explain to me why radio reception is usually better at night.
Also, when I'm tuned into a base station like a trunking system, why does it fade in and out with static all the time, if neither the base or my scanner are moving? This occurs after sunrise...
Cheers
Numloxx[/quote]
it is the Moon..
Can someone explain to me why radio reception is usually better at night.
Also, when I'm tuned into a base station like a trunking system, why does it fade in and out with static all the time, if neither the base or my scanner are moving? This occurs after sunrise...
Cheers
Numloxx[/quote]
it is the Moon..
Hi numloxx
Radio waves can be somewhat complicated to explain. There's lots of reasons why you may notice some signals are better at night than during the day. Here's a starting point:
http://electronics.howstuffworks.com/question1.htm
Follow the links from there and also google around as you think of more questions.
Radio waves can be somewhat complicated to explain. There's lots of reasons why you may notice some signals are better at night than during the day. Here's a starting point:
http://electronics.howstuffworks.com/question1.htm
Follow the links from there and also google around as you think of more questions.
-
w0mbat
- Posts: 110
- Joined: Mon Nov 21, 2005 10:22 pm
- Scanners and Receivers: AOR 8200 MKIII
- Location: Jandakot
Moon??
WTF??
Night reception.
http://www.howstuffworks.com/question1.htm
Fading in and out has always perplexed me too.
Doppler effect somehow? Bit hard if nothing is moving thou.....
Abbsorbsion of the signal somehow.....
The receiver it's self......
Would like the answer too!
WTF??
Night reception.
http://www.howstuffworks.com/question1.htm
Fading in and out has always perplexed me too.
Doppler effect somehow? Bit hard if nothing is moving thou.....
Abbsorbsion of the signal somehow.....
The receiver it's self......
Would like the answer too!
-
WPXZBP
[physics lesson]
A key influence of the propagation of radio signals is to do with a layer of the atmosphere called the Ionosphere. It's a layer of the atmosphere from about 10-600km above the surface of the Earth.
There are three main layers in the ionosphere affecting radio signals. They are the D, E and F layers. The D layer (lowest height of the three) is most responsible for affecting radio wave propagation, causing around 70% on the impact.
During the day atoms in the D layer get hit with radiation from the Sun. This knocks out electrons from the atoms - this is called ionisation. Electrons from ionised atoms absorb radio waves. The lower the frequency, the more they are affected by the electrons. This, in turn, reduces the signal strength. (Frequencies of 10MHz and lower are most affected.)
During the night there is less radiation from the Sun (but still a small amount from cosmic rays) and therefore less impact on radio waves.
[/physics lesson]
A key influence of the propagation of radio signals is to do with a layer of the atmosphere called the Ionosphere. It's a layer of the atmosphere from about 10-600km above the surface of the Earth.
There are three main layers in the ionosphere affecting radio signals. They are the D, E and F layers. The D layer (lowest height of the three) is most responsible for affecting radio wave propagation, causing around 70% on the impact.
During the day atoms in the D layer get hit with radiation from the Sun. This knocks out electrons from the atoms - this is called ionisation. Electrons from ionised atoms absorb radio waves. The lower the frequency, the more they are affected by the electrons. This, in turn, reduces the signal strength. (Frequencies of 10MHz and lower are most affected.)
During the night there is less radiation from the Sun (but still a small amount from cosmic rays) and therefore less impact on radio waves.
[/physics lesson]
