1. Because it is much simpler electronically to encode and decode AM than FM. AM is so easy to detect that it's often done accidentally in amplifiers (like the one I made quickly a couple of days ago which instantly picked up a local transmitter!)
2. I don't think that FM CANNOT do those two things... it's about the frequency, not the modulation type. Low frequencies do those things better than high frequencies and FM (as above) is generally high frequency. (Your guess is correct. Long wavelength = low frequency. That's why radio amateurs interested in long range use long wavelengths, not VHF)
Facts:
1. The cost is entirely in the components used and there is no reason why one should be more expensive then the other. In many (most?) cases FM is cheaper.
2. AM signals and FM signals, under the same conditions, travel exactly the same distance. The kind of modulation does not change the distance it travels,
forte,
Good question.
AM waves echo back from ionosphere. That's the reason why the reach longer distances. Whereas the FM waves travel just like that. So the important point here is: The AM waves hit ionosphere and then get back to the receiver. So it covers larger area.
About the 3rd Question,You have answered a part yourself, Noise alters the amplitude and in AM transmitter,information is superimposed over the carrier frequency,so any change in amplitude,will result in a error in AM receiver...Hi. I am new here and I want to ask some questions related to AM and FM:
1. why is AM is cheaper than FM?
2. why AM can travel further compared to FM?
** for this question, I got several answers such that AM can use ground wave to travel and easier to be reflected by ionosphere. Another questions occur in my mind after reading the answer:
---- why AM can use ground wave while FM can't? I guess the answer is related to wavelength but I don't know for sure
---- why FM is harder to be reflected by ionosphere?
3. why FM is less susceptible to noise rather than AM?
** I know that noise can alter the amplitude of information signal transmitted, but why can't the noise alter the frequency as well?
Thanks for the help
Do not confuse modulation (AM DSB,AM SSB FM, PM,PCM and others ) with the carrier wave.
The frequency of the carrier will determine the propagation characteristics, not the modulation
True, even i had a doubt abt AM, thanks for correcting it.If you FM modulate an HF carrier you will get ionospheric propagation. In the The Ionosphere and Radio Wave Propagation URL the AM is referring to a HF carriers.
True, even i had a doubt abt AM, thanks for correcting it.
but again, i contradict you... FM = MHz ; AM = KHz. So FM is High Freq, yet AM can undergo ionosphere propagation.
You CAN build simple, inexpensive, single transistor FM transmitters and receivers.
You can indeed Super Regenerative FM Receiver using One transistor (BF494) - YouTube
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