Timeline for What are the technical reasons that there are no FM transmissions on the long, medium, or shortwave?
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Aug 30, 2017 at 6:43 | comment | added | AndrejaKo | @resident Multipath propagation is the proof that FM doesn't need line of sight to work well. The signal strength from reflected components can strong enough. For the skywave, I'm not so sure. Here in Europe, CB uses SSB, AM and FM. FM users seem to be in slight majority, but there is still a very large number of AM users. From what I've seen, during times of favorble propagation, FM seems to work more or less same as AM. | |
| Aug 26, 2017 at 6:11 | comment | added | Old_Fossil | Broadcast FM transmitters are usually atop tall buildings and or mountains where the line of sight would easily overcome any small objects like trucks and houses. The is also multipath reception, that is reflected signal as well. Houses that made of wood would be no impediment to RF. | |
| Aug 25, 2017 at 18:21 | comment | added | Mike Waters | @MarcusMüller In North America, broadcast FM is 88-108 MHz and the AM BCB is 540-1700 kHz. Is that different than in Europe? | |
| Aug 25, 2017 at 17:49 | comment | added | Marcus Müller | Needing line of sight for FM is wrong. Ask your car radio. Do you constantly have line of sight to a broadcast tower when driving? Does radio break down every time you pass a house or a truck? | |
| Aug 24, 2017 at 6:47 | comment | added | Old_Fossil | Has more to with way FM receivers decode the signal. I can't at the moment remember all the details (as it is very late-tired). Google FM receiver design and the principles of frequency modulation. | |
| Aug 24, 2017 at 5:44 | comment | added | JanKanis | And by "FM would be unreadable [by skywave]", is that because frequencies are reflected differently by the ionosphere and FM uses a wider bandwidth/more frequencies? Or what happens? | |
| Aug 24, 2017 at 5:12 | history | answered | Old_Fossil | CC BY-SA 3.0 |