Here is my take on this subject...facts and opinions.
This will not happen in the forseable future. I have in the past and recently contacted the CRTC and Industry Canada about this, found someone who knows in the correct dept. and asked if radio will go the way of TV and the answer was there is no plan in the works to do this. The reason TV went this route isn't the same with radio.
TV did this because there would be big difference in picture quality to be gained and since the vast majority of TV watchers were on satalite or cable and few on over the air a very small number of people would be put out and the fequencies could be freed up for other things. And you could keep your old TV by getting a converter that the US government even helped pay for...one per household if I remember correctly. It allowed over the air TV watchers to get the same picture definition as the people who payed since new LCD TVs all came with the digital receivers built in.
Now for radio....my opinions....radio is not the same as TV. People don't care about radio like TV. Lets start with FM.
FM is already high fidelity audio and mostly interference free. Not much will be gained by going digital.....it will sound the same way and the whole population will be affected needlessly. Millions of radios including the hi fi tuner you just spent 2 grand for would be no good. All radios made and for sale are all analog and not digital. How would you put a digital to analog converter on a portable radio?.....FM is fine the way it is, no need to change. If it ain't broke don't fix it!
Now as for AM....yes it does need fixing because amplitude modulation is the worst way of transmission. It's subject to all electrical interference. Way back in the early 20th century when radio was invented and the AM band was set up, this was the way it was invented. Frequency modulation came later in the early 1960s. AM was OK in the past but since the late 80s till now changes happened with hydro till the way it is now causing so much interference and making weaker stations impossible to listen to, strong stations also can't get through the noise. Problem is not to many people even care, but that's besides the point. Or, maybe it is part of the point.
My opinion on a solution....You could covert AM to FM....keep the same frequency range and bandwidth but change from amplitude modulation to frequncy modulation and this would revitalize the "AM" band but this would also mean millions of radios would need to be replaced and would people really care that much? You could also move the "AM" band to 68 to 88 mhz below the current FM band but again this would make everyone need new radios to get the new frequency range. Or the FCC could just care a little about this band and solve the problem of the lousy hydro and this would be the simplest solution. Keep it like it is and fix it.....enforce your own rules about not causing interference.
Take it from me, in my lifetime and from what it seems, the majority of peoples lifetimes on this forum, radio will not change to digital, based on my answers to the people who make these decisions.
Rest easy, our hobby will be here for a while.
Also remember....records, turntables, and integrated amps are all making a comback! And not just with "old" people and this is all analog!
Mark
If AM did start transmit using an FM signal the old analog turn your dial Radio's could still receive the station but the quality would be a little less. You'd do it the same way as a kid you received air craft using a dial Radio. You tune to the right side or left side of the carrier and the volume gets louder instead of just hearing the FM carrier and not the voice. Its the oldest trick in the book, but back then before I had a police scanner and I had a Radio with the public service band and aircraft band that was how I had to receive AM. FM on an AM Radio would be sort of the same way. The new Radio's would have a nice clean signal on the AM band. Another way to fix AM is for the FCC to force receivers to be made better with the proper filtering. Radio's were better in the 70's than they are now. There is no excuse for these poor receivers to hit store shelves. Instead of stations transmitting more power its time to make the power they have now be used more Efficiently. Hams have learned this a long time ago. Plus we'd save energy for the planet in the long run too to boot. So yes AM could be fixed and you could have Album Rock on it if receivers were made better and all this interference were gone. Then it would be fun to transmit on AM.
My prediction is in ten years AM radio will go digital in the USA. This may be the timeline to "start" the conversion, and the sunset date will be set for traditional AM radio as we know it today. Nine stations around the country have just wrapped up some rather extensive testing.
I could be wrong of course, but I read all the trades every month, and I talk with people in the industry, and everyone behind the scenes is gearing up for the change. They want to be prepared.
I did see that last year the sales of albums on vinyl was up 38 percent. For 2014 3.6% of new albums sold were on vinyl. That figure, BTW is 3.6% of PHYSICAL ALBUMS SOLD, so that's CD's vs vinyl, it doea not take into account downloads of music.
Anyway, intersting article:
http://www.radiomagonline.com/rf-engineering/0030/what-is-the-status-of-alldigital-am/36617
My prediction is ---- 10 years ----
Tim in Bovey
Amplitude Modulation does not attract static from storms. It is the medium wave band that is statically polluted by lightning, and this continues up into the shortwave band and starts to roll off somewhere around 50 MHz.
Amplitude Modulated audio response is limited by the bandwidth of the signal, only 5 kHz. If the channel space for a MW signal was expanded to 40 kHz then amplitude modulation would sound just as good as frequency modulation, but there wouyld be far fewer channels between 530 and 1700 kHz.
Ok the police band 460 Mhz uses 12.5 Khz steps. If AM goes Digital you could get a lot more channels in the same space than analog FM can. I think they will start making digital Radio's that can also receive analog as well. Some stations may transmit both for quite some time. Here is a question isn't HD Radio the same as Digital? Am I missing somethig? HD Radio has not really caught on much in the USA and the only Radio's I've seen was in cars. My friend had one and it did sound really nice. One Classic Rock station in the Detroit area years ago started playing Real Album Rock deep tracks only on the HD side. But he said if he went 30 miles away from the city all the HD stuff started to chop in and out.
If Radio goes digital I don't see them taking away analog from part 15. This could be a good thing, but if they try and cram more stations that would be bad unless they use the HD 2.3.4 for different stations on the same frequency. Then the band will have more room. Still I say 15 years till all analog Radio is gone and that day depends on the folks using their smartphones to replace Radio. The NAB wants cellphone carriers to stop blocking the FM Radio's in these devices. I'll be glad when that happens.
Let's say that radio did go digital similar to TV....this hobby would be dead. There would be no transmitters made to transmit this and digital doesn't work like analog in just finding an unused frequency and setting your micro powered transmitter to that. The systems would all be owned by a corporation. Analog is not patented. If AM goes digital, your SStran is garbage, so is your decade or wholehouse if FM goes digital, and if you just transmitted like before it would be for yourself because no one could get it on a digital radio. Frequency bands, allocated frequencies for stations and empty space....is not like this with digital.
Lets say that Timinbovey is right that in 10 years whether just AM, or AM and FM will go digital, that would be just the announcement that it is finalized and a further 10 years of coversion time and advertizing it so we would gradually be eased into this. So 20 to 25 years before the sun would set on radio as we know it and our hobby. probably after my lifetime(wishfull thinking). But as I said based on what the CRTC and Industry Canada told me no plan to phase out conventional radio is in the near future and working out the way it would work would take some time.
When TV did this it was announced first and there was a 10 year gradual getting us used to it before the final date when it would become manditory. And during that 10 years TV makers started discontinuing CRT TVs to make LCDs with the digital receiver built in. All radios and Hi fi tuners are not made to receive digital and no car I've ever heard of has a digital radio.
This is just in the disscussion stage only, an idea for the future.
Back in the 70s we were talking about domed cities but that has never come about.
We don't want digital radio....the hobby would be dead.
Mark