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Three years ago, Norway switched off all main network analog radio leaving only DAB+. It took a year for ratings to recover and now there are more listeners than ever.
2CH also has another advantage that they are no longer paying for an AM transmitter and its maintenance, depreciation and electricity consumption. Remember that more than half of the electricity consumed went to produce the AM carrier which contains no information at all. In DAB+ there is no carrier and one transmitter is sharing more than 18 programs.
Congratulations to 2CH on the conversion of the audience which proves we could switch off all AM and FM city wide transmitters in all capital cities now, saving not only a lot of money for broadcasters but in all states except Tasmania a big reduction in greenhouse gasses.
If anything I would suggest older listeners (like myself) are more likely to be listening via DAB than younger people. Most times when I hear 4KQ in shops etc around Brisbane it's via DAB not AM. Yet operators like ARN just refuse to promote DAB - I just don't get it!!! Kudos to 2CH for actually promoting DAB.
I fully concur with Mr St. John that most of the electricity consumption of an AM transmitter is in the carrier. Recall that a MW AM signal consists of the carrier and its upper and lower sidebands.
The AM carrier is transmitted in order for receivers with diode envelope detection. Diode envelope detection has been used as an envelope detector from simple crystal sets to most MW AM receivers.
If all AM receivers had a synchronous detector, there would be no need for the AM broadcaster to transmit the carrier. The broadcaster would save money on electricity consumption.
Unfortunately, "the toothpaste cannot be placed back in the tube" OR "you can't unscramble the egg". In this case, a broadcaster cannot suppress the carrier because no one will be able to receive AM broadcasts via an envelope detector.
Thank you,
Anthony of exciting Belfield
Dear Mr St. John,
I fully concur with you that you would not push for AM receivers with synchronous detection. It's too late, you "cannot unscramble the egg". In 'theory' synchronous detectors should have been made mandatory under the law administered by the PMG and Australian Broadcasting Control Board. Again, it's too late.
Having said that, SDR implementations of AM radio do have digital filtering techniques to significantly noise, 9kHz whistling and 'monkey chatter'.
FM's RDS system is too slow only enough to promote limited news, weather and tune information.
The potential of DAB+ has not been fully exploited with enhanced features such as journaline, TPEG and emergency wakeup. The same could be said about DRM+'s potential, a topic you have been crusading many times on this website. This is especially that DRM+'s being suitable for overseas and rural transmissions.
My question to you is if an emergency system is implemented under the DAB+ or DRM+ and the NBN and mobile phone systems are out-of-action, do you need a separate broadcast tower and mobile phone tower and separate power supplies?
What about a reliable link between the studio and transmission tower that is not delivered by the internet?
For example you mentioned a few times on this site, the devastation in Bateman's Bay of the bushfires destroying the ABC transmitters source, 4th June, 2020, 1:32pm, https://www.radioinfo.com.au/news/telephones-weak-link-remote-broadcasting.
If the ABC in Bateman's Bay implemented a DAB+ or DRM+ with the transmission/reception system capable of journaline, TPEG and wakeup facility how would you prevent the broadcast transmitters from being destroyed again as happened during the bushfire?
In addition how would a link between the studio and transmitter be implemented without going through the internet = NBN?
Thank you,
Anthony of curious Belfield
Anthony,
I would not push for new receivers with synchronous detection, digital reception has a lot more to offer. Such as;
stereo sound and the high pitched sounds that virtually all AM receivers remove to prevent interference particularly at night.
The parts of DAB+/DRM which are not being used in Australia are
Slideshow for images on the radio screen. The ABC transmits only an icon
Journaline which is an indexed many page text system, which could create an electronic newspaper.
The transmission of TPEG data so that road closures etc can be sent directly to vehicle navigation systems to re-route traffic. FM's RDS does it but it is very limited in the number of changes because of the very low available data rate.
Most importantly with the severe fires and storm events the Emergency Warning Functionality is yet to be used. This is where when a receiver is in the emergency area, it and the listener can be woken, a voice announcement is made along with a map and detailed instructions on what to do along with road closures sent to vehicles. This system can work when the mobile phone system and NBN cannot be relied on.