FM Frequency Converter

With the plethora of Japanese imports coming into Australia  – what with the 15+ year old cheapies and the more recent crop of cars boasting high tech sound systems – more and more people are needing to fit an FM frequency converter. Well, what’s that then? A frequency converter is needed in these domestic Japanese imports because Japan’s FM radio frequency range is different from Australia’s (and most other countries as well). In Japan the frequency range is 76 - 90 MHz while – for example – in Australia it’s 88 – 108 MHz.

Bottom line is that when you try to tune in your favourite station, it might not be there!

The frequency converter splices into the aerial line and alters the received frequency by a preset amount, putting all stations within the radio’s range of reception. The PB1000-10Mhz unit we used in this story – made by Electronic Developments of New Zealand and available through Jaycar Electronics or the AutoSpeed shop – subtracts either 10 or 20 Mhz from the incoming signal.

The result looks like this:

Receiving Frequency(Mhz)	Displayed  Frequency (76-90Mhz )
Frequency is shifted downwards by 10 Mhz
88	78
89	79
90	Blank Spot
91	81
92	82
93	83
94	84
95	85
96	86
97	87
98	88
99	89
100	Blank Spot
Frequency is shifted downwards by 20 Mhz
100.1	80.1
101	81
102	82
103	83
104	84
105	85
106	86
107	87
108	88

(Check the box below for more on ‘Blank Spots’)

Of course, when you’re using the frequency shifter, you don’t really need to worry much about the amount of frequency shift that has occurred – you just find your favourite stations and then set the presets.

Blank Spots and Double-Ups All frequency shifters have two downsides. The first is that there will be two specific frequencies at which the radio no longer works. If the frequency shift is 10 MHz, there will be blank spots at 90 and 100. If the frequency shift is 12 Mhz, the blanks will be at 96 and 108. So if you have a favourite station that coincides with one of these frequencies, you need to pick the frequency shift unit with care. The second of the downers is that if there are two FM stations broadcasting apart by the same frequency difference as the frequency shift, (eg 10 MHz apart with a 10 MHz shifter) then they will double-up. A range of frequency shifters is available - Electronic Developments will help you select the most suitable frequency shifter for your application – www.edl.co.nz

Advantages

There are two major advantages of using a frequency shifter:

1)       You don’t need to buy a new radio, which saves you a lot of cash!

2)       You can preserve the original look of the dash – whether that’s retaining a classic look in an older car or letting you keep the factory integrated controls and visual display units in a more current model

Installation

Installing a frequency converter is really easy.

The converter has a single wire that’s connected to ignition-switched 12V (the earth is through the aerial connection), a plug that connects to the head unit, and a socket that connects to the lead coming from the aerial.

The aerial socket on this Toyota head unit is a standard size. However, in some cases there will be a non-standard socket fitted, which will require an adaptor harness. Check before you buy.

Remove enough trim so that access to the aerial socket of the head unit can be gained. Plug in the adaptor then...

..connect the other lead to the original aerial plug.

The metal box of the adaptor should now have continuity to ground – you can check that with a multimeter if you like.

You’ll next need to find an ignition-switched 12V supply. That is, a wire that has 12V on it when the ignition is at the accessory position and 0V when the ignition key is turned right off. Here the power is being picked up from the back of the cigarette lighter socket.

A crimp-type electrical connector is supplied with the frequency shifter, making the power connection quick and easy.

After that it’s just a case of checking that the frequency shifter is working and then reinstalling all the trim. The box is light enough that it can be left floating or you can cable-tie it into place.

Finished! Now you can listen to all your favourite radio stations!