Questions tagged [fm]
Questions about Frequency Modulation, the analog modulation scheme commonly used for voice on VHF and UHF frequencies.
13
questions
4
votes
2
answers
2k
views
How does FM station have fixed frequency when FM modulation changes the frequency?
I am not sure if this question fits better in physics.stackexchange or ham.stackexchange, feel free to correct me. I am new to studying RF and SDR in general, I was looking up how modulation works and ...
3
votes
2
answers
485
views
Can two FM radios transmit two separate PL tones at the same time, and be received by two radios with matching PL tones?
Can two FM radios transmit two separate PL tones, and be received by two radios with matching PL tones? Or will the receivers hear a mix of the two, or nothing at all?
- 709
12
votes
3
answers
610
views
Resort FM radio station
I stayed at a resort in the U.S. recently that is located in an unpopulated area with virtually no radio reception. To fill the gap, the resort has its own FM station that can be heard only within ...
- 223
11
votes
1
answer
2k
views
Is FM modulation still more resistant to noise when given the same bandwidth as an AM signal?
FM modulated radio is much more resistant to noise and can deliver better sound quality than AM radio. But FM signals also use more bandwidth than AM signals. In general a wider bandwidth signal is ...
- 405
8
votes
1
answer
481
views
Is FM appropriate for foxhunting?
I'm thinking about an inexpensive way to create a foxhunt kit for youth groups, and am wondering if the cheap dual band HTs could be used.
However, it occurs to me that FM doesn't provide any good ...
- 12k
7
votes
3
answers
10k
views
Single Side Band AM vs FM
I know the difference between AM and FM, but could anyone explain to me what is the differences between single side band AM and conventional FM?
So far as I know the SSB modulation will reduce the ...
- 173
6
votes
3
answers
4k
views
What does the term 3 kHz deviation relate to in the FM world?
I am confused when someone says "your audio levels are set right and has good deviation at 3 kHz" when talking about wide-band 25 kHz FM signals.
First confusion: Why are audio levels measured in ...
- 7,510
4
votes
3
answers
1k
views
What are the technical reasons that there are no FM transmissions on the long, medium, or shortwave?
Why are there no frequency modulated broadcasts on the long/medium/short wave, but only on VHF? I'm sure there are many historical and political reasons (long/medium/short wave were already in use for ...
- 405
4
votes
4
answers
3k
views
What does multi-path sound like on FM?
I know I have probably experienced multi-path propagation on FM modes when I was working a repeater in the grand canyon and in the mountains. How can I identify when I am getting multi-path, and what ...
- 7,510
3
votes
1
answer
204
views
How do PL tones make it through so much noise?
So sometimes I hear people trying to get into a repeater with pure noise, and no audible audio on their transmission.
With the repeaters that require a PL tone, how can the PL tones get through all ...
- 7,510
2
votes
3
answers
264
views
Store and forward system like voicemail for hams
I want to be able to get in touch with hams in my area when we are not both on air at the same time, but are close enough to each other for VHF communication. I want to be able to use my radio to call ...
- 133
0
votes
3
answers
80
views
change LC parameter digitally
LC circuit is the main element of every frequency generator, I intend to make an FM transmitter, but many opensource circuit use analog variable L or C part to set and adjust the target frequency
My ...
0
votes
1
answer
212
views
What determines the bandwidth of an FM signal?
With an FM signal, it takes up more room in the radio spectrum presumedly because the carrier frequency is changed. On average what's the width of the FM sidebands?
Does the deviation from the center ...
- 7,072