The frequency range of the Australian AM band is from 531kHz to 1602kHz but recently a range above the top of the band (from 1611kHz to 1705kHz) has been allocated to "narrow band area services". Community radio stations have been allocated frequencies in this new band. They operate on low power and are only meant, as the name implies, to cover a small area within a radius of 20-25km.

They operate on a restricted bandwidth (narrow band) of ±3kHz and because of this, they do not transmit wideband hifi sound. (Other AM stations do broadcast hifi sound but you’d never know it because most AM radios produce poor quality sound). For their intended use, community news and information, the narrow audio bandwidth is not a major drawback.

This Digitor AM/FM radio costs $12.95 from Dick Smith Electronics. It already covers all the new community stations without modification. Alternatively, you can tweak an old AM receiver if you have one lying around.

The problem is that normal AM receivers, and especially AM/FM tuners with digital displays, will not cover this additional range. The same comment applies to car radios. So why not design a down-converter which would translate these stations into frequencies which can be tuned by a standard receiver? When we looked at the cost of a small AM/FM radio, we realised that the "converter" would cost many times more than the radio.

We therefore decided that, in view of the cost of a down-converter and the relative difficulty in connecting it to an AM/FM tuner or car radio, the project was not really viable.

OK then, could we convert an "off-the-shelf" AM radio to cover this extended band? Being the last of the big spenders (and having to get the money back from the boss), we bought a $12.95 Digitor AM/FM pocket radio from Dick Smith Electronics.

When we got it back to the lab and opened the box, one of the interesting things about the radio was its dial coverage. It was scaled from 520kHz to 1710kHz, which meant it should already cover all the new stations.

Checking this range using a signal generator showed that it actually tuned from 537kHz to 1720kHz. So who needs a converter? Just buy this radio and the problem is solved.