It's not necessarily clear cut for one being more reliable than the other. FM broadcasts are analog and more likely to be subject to interference (interference will directly impact what you hear, but not as badly as with AM radio) and as the signal falls off it will be harder to hear. Digital radio will be perfectly clear as long as you get a signal, but may become distorted or just cut out if the signal is weak and there are too many errors in the data being received. There will be error correction for digital radio signals, but eventually you won't be able to receive reliably enough that it will fail. If I had to guess, assuming all of the equipment is working, digital is probably going to be more reliable than analog radio in more conditions and over a longer distance, and it probably needs less bandwidth in general because you could compress the stream.
I'd argue it is still less reliable since the channels are multiplexed. This means a failure of single transmitter takes down all of those channels at once. Secondly, digital radio often uses SFN to save bandwidth and power. This however means that a single misconfigured/malfunctioning transmitter can cause destructive interference in a wider area.
This is happening in my area for a few months now. A new low power DAB+ transmitter was added into the network. I was able to get a poor but still usable signal before, while now the signal is strong, there's too much interference for the error correction to compensate. Someone on a forum from this area has mentioned the same happening to him after the addition of this transmitter, when trying to tune DAB+ in his car.
But sure, if the technology works, it can be better.
For sure! There's definitely going to be problems with digital radio when it's used to cram more channels on the same frequency band or whatever. But the particular implementation of broadcast digital radio aside, if we're just talking modulation, I would bet on digital modes being able to transmit further more reliably than any analog FM signal.
I know that some of the digital modes like FT8 that hams use can be super effective at making long distance contacts in low noise environments. Of course these are text modes, and not used for voice. I'm not sure whether or not something like FT8 will do better than regular CW in the same conditions, but I wouldn't be terribly surprised if it could… Being able to do error correction for signals would likely make a huge difference in noisy environments.
AM transmitters / receivers are far easier to construct than FM ones, though. If I was in an emergency situation where I couldn't communicate with anybody I think I might be able to at least make an AM receiver, even if there aren't very many components around… But I would need a reference to have any clue how to approach an FM one, and you'd definitely need more components available. Frequency modulation is quite a bit more complicated. If you want to transmit, CW is probably your best hope?
Realistically, though, almost anybody in an emergency situation is doomed if the only thing that would save them is building any kind of radio. It's not a skill set that most people have… Which I guess is why you might advocate for everybody's phones to be able to act as FM receivers in case that's the best way to get an emergency broadcast, because then they would have a device that's capable of it on hand. You're probably better off if you have a dedicated emergency radio, especially if you might lose power for an extended period of time, though.
Best part about a simple AM receiver is that it doesn't need a battery… For emergency situations it'd definitely be best as it's dead simple to construct, you can boost gain in radio station for more reach / power to the battery-less receivers, etc. and the transmitters are simple, too.
For emergencies it's also not a bad idea to have an offline copy of Wikipedia.
A 400 kHz wide channel is required for HD FM analog-digital hybrid transmission, making its adoption problematic outside of North America. In the United States, FM channels are spaced 200 kHz apart as opposed to 100 kHz elsewhere. Furthermore, long-standing FCC licensing practice, dating from when receivers had poor adjacent-channel selectivity, assigns stations in geographically overlapping or adjacent coverage areas to channels separated by (at least) 400 kHz. Thus most stations can transmit carefully designed digital signals on their adjacent channels without interfering with other local stations, and usually without co-channel interference with distant stations on those channels.[7] Outside the U.S., the heavier spectral loading of the FM broadcast band makes IBoC systems like HD Radio less practical.
The FCC has not indicated any intent to end analog radio broadcasting as it did with analog television,[2] since it would not result in the recovery of any radio spectrum rights which could be sold. Thus, there is no deadline by which consumers must buy an HD receiver.
Maybe some other place.
EDIT: Some countries in Europe apparently have, and some are scheduled to do so in the future.
Analogue radio is getting shut down in favor of digital broadcasts, so I doubt this would truly be helpful in many areas.
Aren't digital radio less reliable than analog FM broadcasts? Would digital broadcasts be as useful during an emergency?
I don't really know that much about the subject, so I'd like to learn a bit more.
It's not necessarily clear cut for one being more reliable than the other. FM broadcasts are analog and more likely to be subject to interference (interference will directly impact what you hear, but not as badly as with AM radio) and as the signal falls off it will be harder to hear. Digital radio will be perfectly clear as long as you get a signal, but may become distorted or just cut out if the signal is weak and there are too many errors in the data being received. There will be error correction for digital radio signals, but eventually you won't be able to receive reliably enough that it will fail. If I had to guess, assuming all of the equipment is working, digital is probably going to be more reliable than analog radio in more conditions and over a longer distance, and it probably needs less bandwidth in general because you could compress the stream.
I'd argue it is still less reliable since the channels are multiplexed. This means a failure of single transmitter takes down all of those channels at once. Secondly, digital radio often uses SFN to save bandwidth and power. This however means that a single misconfigured/malfunctioning transmitter can cause destructive interference in a wider area.
This is happening in my area for a few months now. A new low power DAB+ transmitter was added into the network. I was able to get a poor but still usable signal before, while now the signal is strong, there's too much interference for the error correction to compensate. Someone on a forum from this area has mentioned the same happening to him after the addition of this transmitter, when trying to tune DAB+ in his car.
But sure, if the technology works, it can be better.
For sure! There's definitely going to be problems with digital radio when it's used to cram more channels on the same frequency band or whatever. But the particular implementation of broadcast digital radio aside, if we're just talking modulation, I would bet on digital modes being able to transmit further more reliably than any analog FM signal.
I know that some of the digital modes like FT8 that hams use can be super effective at making long distance contacts in low noise environments. Of course these are text modes, and not used for voice. I'm not sure whether or not something like FT8 will do better than regular CW in the same conditions, but I wouldn't be terribly surprised if it could… Being able to do error correction for signals would likely make a huge difference in noisy environments.
In a life or death situation it would be easier to construct an FM transmitter/receiver than a digital counterpart.
AM transmitters / receivers are far easier to construct than FM ones, though. If I was in an emergency situation where I couldn't communicate with anybody I think I might be able to at least make an AM receiver, even if there aren't very many components around… But I would need a reference to have any clue how to approach an FM one, and you'd definitely need more components available. Frequency modulation is quite a bit more complicated. If you want to transmit, CW is probably your best hope?
Realistically, though, almost anybody in an emergency situation is doomed if the only thing that would save them is building any kind of radio. It's not a skill set that most people have… Which I guess is why you might advocate for everybody's phones to be able to act as FM receivers in case that's the best way to get an emergency broadcast, because then they would have a device that's capable of it on hand. You're probably better off if you have a dedicated emergency radio, especially if you might lose power for an extended period of time, though.
Fair point.
Best part about a simple AM receiver is that it doesn't need a battery… For emergency situations it'd definitely be best as it's dead simple to construct, you can boost gain in radio station for more reach / power to the battery-less receivers, etc. and the transmitters are simple, too.
For emergencies it's also not a bad idea to have an offline copy of Wikipedia.
Kiwix is great and Wikipedia is surprisingly small :).
Where?
Norway has been like this for many years now.
I think in the US.
Not in the US.
https://en.wikipedia.org/wiki/HD_Radio
Maybe some other place.
EDIT: Some countries in Europe apparently have, and some are scheduled to do so in the future.
https://www.radioworld.com/news-and-business/switching-off-fm-in-norway-and-soon-switzerland
This has Norway having killed FM in 2017, and Switzerland scheduled for 2024.
My bad, I was wrong.