Yesterday I was despairing of finding the perfect FM 'deadzone', or quiet spot on the radio dial that could be utilised by my Griffin Roadtrip, a widget that streams songs from your iPod to your car stereo via a narrowcast, in-car FM transmission.

I appealed to lecturer Andrew Dubber - perhaps New Zealand's leading radio expert (if currently on secondment to a university in the UK) - for assistance. Herein lie the Dubber Files:

Hi Andrew,

I'm currently road-testing Griffin's RoadTrip iPod FM transmitter and am having two inter-related problems:
1) Where can I find a listing of all FM broadcasters in Auckland (and NZ) and
2) Can you recommend the ideal FM dead zone in Auckland.

Currently I'm beaming songs from my Griffin to my car stereo on 88.1 which is good for around Mt Eden and elsewhere, but gets a lot of interference once I hit K-Road and the CBD.

Thanks,
CK

Hi Chris,

There's good reason for that interference. You're sitting in the only country in the world where any citizen who wishes to broadcast can just turn on a transmitter and start talking. They have to be of a certain power output (under half a watt) and in a certain area of the spectrum, known as the 'guard band'.

In fact, there are two guard bands: One from around 88-89MHz (which is a problem in Auckland, because Mai FM is already there) and another between 107 and 108. It's called a guard band, because its intention is to protect different services from each other by allowing no high powered transmissions in between, say FM broadcast and Air Traffic Control.

Since it's actually possible to transmit over about a 2km radius with under half a watt, given a bit of height and some serendipitous terrain, Low Power FM stations make the most of the rules by picking densely populated areas. As a result, there are quite a few inner-city LPFM stations. I'm surprised that you're not getting interference in Mt Eden, actually -- and if I was living in NZ the first thing I'd be doing right now is setting up a low power FM station for the Mt Eden community. Probably on 88.1FM.

However, the Griffin will give you the complete spectrum to play with, and you may actually be better off finding gaps up the other, less densely packed end of the spectrum. Most larger FM stations in NZ are spaced 800kHz apart (ie: 89.4FM, 90.2FM, 91.0FM, 91.8FM) so you might
find that a centre point between those stations might be a better option. The upper end (in the 101-107 range) is still less densely packed with radio stations.

The Ministry of Economic Development's Spectrum Management Services will have comprehensive listings of all licensed radio stations (try: spectrumonline.med.govt.nz/).

The Society for Low Power FM Broadcasters maintains a list of all the current unlicensed micro-broadcasters, and it will probably be pretty much up to date -- at least for the Auckland area where the society is based: www.lpfmnz.com/modules/stationdb/

Wikipedia has a list of radio stations in NZ(en.wikipedia.org/wiki/List_of_radio_stations_in_New_Zealand) but it isn't sorted by frequency, so it's not very helpful for your purposes.

Good luck finding a dead spot in the most 'radioed' city on the planet.

Cheers,
Andrew

Andrew Dubber
Senior Lecturer in the Music Industries at UCE Birmingham
and author of the New Music Strategies Manifesto:
www.newmusicstrategies.com/manifesto