There are some things which you need to know about broadcasting your display over the FM band before you flick that dial. Depending on what you want to do, to run a legal broadcast may cost or it might not.
This article is intended for Australian audiences only.
There are two bodies that are involved in the broadcasting domain within Australia. They are:
ACMA deal with restricting and granting many types of broadcasting, including FM broadcasts.
APRA deal only with the use of commercial music in public (which includes FM broadcasts in respect to Christmas displays)
Can I broadcast?
Yes, any resident can broadcast over FM subject to many restrictions. Christmas display seasonal broadcasts are categoried by the ACMA as open narrowcasting services which is defined as being: services directed at special interest groups or that are provided only in limited locations or during a limited period or to cover a special event or that provide programs of limited appeal.
The ACMA permits individuals to use broadcasting equipment rated up to 10µw (microwatts) without paying for a licence. Any signal which is stronger than this must have a licence for legal transmission. Christmas displays on private property which are free of admission and do not make any form of monetary gain (from advertisements or otherwise - this includes signs for newly installed roller shutters) may be able to apply for a temporary community licence (fee applies) to transmit using equipment rated more than 10µw.
How to choose a frequency
In short, always choose an empty frequency! Give yourself a buffer of 400 kHz either side of your intended frequency to ensure you aren't competing with another broadcast. In Australia, the FM broadcast frequencies range from 87.5 to 108 MHz (see ACMA).
To find out what is broadcasting near you, type in your postcode on the online ACMA broadcasters search function. Checking for radio stations yourself by scanning with a receiver is a less reliable method as it may not identify all the licenced stations near you due to a weak signal.
Transmitting on a licenced frequency is a bad idea, as it not only may cause interference with your own transmission, but also interfere with the licenced radio station. In some cases a complaint could be lodged with the ACMA either from a listener or even officers from the affected radio station. The ACMA may ask you to stop broadcasting or potentially seize your transmitter.
What about copyright music?
Australian law states that rightfully purchased music is authorised for personal use only. This does not extend to playing over outdoor speakers for a purpose other than for your own listening, nor does it apply to broadcasts except under very limited circumstances (such as an ipod broadcasting to your car's radio).
APRA come in to play when using copyright music in your display without the direct permission of the author. It is possible to request legal use of copyrighted music in your display without payment of a fee. The licence which you will need is the APRA Narrowcast Complimentary Licence. The conditions of obtaining such licence include that:
the display must be operated by an individual and not a corporate identity
the display must not air or display any advertisements
the display must be on private property (e.g. not a retail store, shopping centre, park)
no money can be rasied either from admission, voluntary donations, or otherwise (note: donations to known charities exempt)
all music must be legally acquired (purchase of an album, purchase from iTunes)
Ok, I'm ready to get my APRA licence
If your display meets all of the above conditions, you should be eligible to apply for a free licence for the use of copyright music. Your licence will only cover a short period, and must be reapplied for each year. The dates of your licence should cover the first day that you will be running your transmitter (for testing purposes) right up to and including the final day of transmission (usually the last day of your display).
You should contact the APRA Narrowcasters department by email:
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Please note that even with a valid APRA licence, if your transmitter exceeds 10µw then you still need a broadcasting licence from the ACMA to legalise the use of the transmitter (fee applies). APRA licences cover the use of copyrighted music only and not transmitter operation.
Disclaimer: This article is not a replacement for proper legal advice.
What equipment do I need?
Example of FM transmission equipment connectivity
In order to run a broadcast properly you will need:
A low-power FM transmitter
An antenna of some sort
An amplifier (if transmitter has no volume control)
A music source (nearly always the device that runs your show, be it a standard computer or Raspberry Pi)
An audio cable from the music source to the transmitter (for computers the output is often a 3.5mm green coloured line out socket). Depending on the transmitter model the input connection may require:
A stereo 3.5mm jack to 2x RCA jack cable (for transmitters with RCA input) or a stereo 3.5mm jack to stereo 3.5mm jack cable (for transmitters with 3.5mm input)
The FM Transmitters article covers the more technical aspects of FM broadcasting.