WA Radio Scanner Users' Group

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="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..

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.

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!

[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]

Is it that which causes the 'pulsing' of the signal or reception?

The pulsing is sort of like a wave with the peaks about 3 seconds apart.

Thanks

--Steve

Thanks guys

I could be cheeky and say "some people could do with an Amateur Foundation course" ... but I won't

hehehe give me time I'm getting there eventually...hopefully!