Poor radio reception on Japanese head unit equipped with Band Expander

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jasonwaiheke

277 posts

Ultimate Geek

#115931 12-Apr-2013 11:13

Hi all,

my car has a Japanese radio with a band expander fitted to get NZ stations, i can pick them up no problem but the reception is poor on some and bad on others. is there anyway to improve recpetion without replaceing the head unit as it is connected to a rversing camera, and i dont want to go down the road of loosing that or buying an expensive headunit.

johnr

19282 posts

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Inactive user

#798307 12-Apr-2013 11:16

Head units are cheap as chips pop into repco and super cheap auto and have a look

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ubergeeknz

3344 posts

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Vocus

#798309 12-Apr-2013 11:18

Some expanders are better than others. Also make sure if it has two antennae (diversity) that you have 2 (matched) band expanders.

nickb800

2699 posts

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#798312 12-Apr-2013 11:21

I'm in a similar situation with a jap import, and after replacing the stock radio with band expander with a high-end Pioneer headunit, reception still isn't 100%.

My car has a series of metallic tracks on the rear windscreen for an antenna (just like the demister wires) and my theory is that the gap between these wires is set to the wavelength of japanese FM radio (76-90) and thus doesn't do a great job of picking up NZ FM radio (88-108). I haven't looked into it too far, but if the reception is worse with higher frequencies then this may support the theory. Or I could be completely wrong. If I'm on the right track, installing a conventional wire antenna might help.

ubergeeknz

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Vocus

#798313 12-Apr-2013 11:23

nickb800: I'm in a similar situation with a jap import, and after replacing the stock radio with band expander with a high-end Pioneer headunit, reception still isn't 100%.

My car has a series of metallic tracks on the rear windscreen for an antenna (just like the demister wires) and my theory is that the gap between these wires is set to the wavelength of japanese FM radio (76-90) and thus doesn't do a great job of picking up NZ FM radio (88-108). I haven't looked into it too far, but if the reception is worse with higher frequencies then this may support the theory. Or I could be completely wrong. If I'm on the right track, installing a conventional wire antenna might help.

That would be the case, yes. Again though, some headunits are better than others too. In my experience the best tuners are the Sony ones, unfortunately their headunits are otherwise not great compared to pioneer etc.

grant_k

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#798330 12-Apr-2013 11:48

I had a Sony headunit in a Japanese import and whilst it was great for playing CDs, it was crap for FM radio reception. This turned out to be caused by the crappy "band expander" which was poorly designed so you ended up with images on top of the real stations. For example, in Auckland I couldn't receive National Radio on 101.4MHz because Newstalk ZB on 89.4MHz was right on top of it.

The only solution was to ditch the imported head unit and replace with a double-DIN JVC which did the job very nicely. FM radio reception was improved out of sight with exactly the same antenna.

ajobbins

5050 posts

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#798342 12-Apr-2013 12:10

People still listen to the radio?

I just bluetooth my music direct from my phone to the headunit in the car.

Twitter: ajobbins

ubergeeknz

3344 posts

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Vocus

#798344 12-Apr-2013 12:11

ajobbins: People still listen to the radio?

I just bluetooth my music direct from my phone to the headunit in the car.

No headunit at all for me, phone feeds straight into an EQ. No FM reception = no FM reception problems!

Goosey

2341 posts

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Subscriber

#798367 12-Apr-2013 13:22

You need an aerial booster.
Similar price to the band expander and looks like a thick metal pen.
Not sure if you can combine the booster with the expander as I suspect some boosters also do the expanding.
Best you visit a car audio installer and have a chat to them OR repco, supercheap etc.

There are different qualitys of boosters and expanders (internal components)....you get what you pay for.
What kind of car is it? What type of aerial and where is it mounted.

ALSO: its well known that cheap/poorly mande band expanders will degrade over time.

jasonwaiheke

277 posts

Ultimate Geek

#798404 12-Apr-2013 14:09

Thanks guys, I have a Toyota Ipsum 240S 2001 with a standard Japanese head unit designed to work with the reversing camera. There is no visible aerial, and the band expander came installed by the dealer / previous owner? the only thing I can think of is that the areial is some of the previously mentiones wires in the back window, which are obvioulsy not that great. FM reception in many areas of where we live is not 100% fantastic anyway. WhenI say I get poor reception, it is not stations overlapping, it is just not clear, little bit of static, and does not lock on stereo.

grant_k

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#798414 12-Apr-2013 14:21

jasonwaiheke: Thanks guys, I have a Toyota Ipsum 240S 2001 with a standard Japanese head unit designed to work with the reversing camera. There is no visible aerial, and the band expander came installed by the dealer / previous owner? the only thing I can think of is that the areial is some of the previously mentiones wires in the back window, which are obvioulsy not that great. FM reception in many areas of where we live is not 100% fantastic anyway. WhenI say I get poor reception, it is not stations overlapping, it is just not clear, little bit of static, and does not lock on stereo.

I have had several vehicles now which use the "wires in the window" for an aerial. They all work perfectly so long as you have a headunit designed for the worldwide (except Japan) band. That is your problem and in my experience, no amount of antenna boosters, band expanders etc will fix it. Reception will always be poor until you change to a locally-sourced headunit, which as JohnR pointed out, are now cheap as chips. It all comes down to whether you value your FM radio reception, or reversing camera the most. For me, it would be the radio, as you can always fit an aftermarket screen for your reversing camera.

jonherries

1311 posts

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#798416 12-Apr-2013 14:24

I have a Japanese Golf, and the forums suggest an antenna booster as this is often a problem for these cars. You run it off the accessory wire.

I wish I had thought to do that before reassembling my dashboard...

Jon

Goosey

2341 posts

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#798445 12-Apr-2013 14:54

Find yourself a easy to install rubber ducky aerial or somthing you can install yourself. The glass shield aerial is the problem in the first instance.

e.g you could attach it to the side of the boot.
I managed to get away with just running the aerial lead to the boot and attaching the centre pin to the boot weld (I sanded it back to expose bare metal). This was in a 1978 celica and recieption was fantastic.

richms

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#798546 12-Apr-2013 17:55

cant fit 20mhz of band into 14mhz of the japanese band.

If you want reliable radio reception get a radio designed for the nz band plan. Basic local oscilator band shifting only works if all freqs are about the same strength.

Richard rich.ms

SATTV

1480 posts

Uber Geek

#798587 12-Apr-2013 20:13

I removed my radio and tool the lid off, i moved a resistor to another spot ( it was well marked ) and hey presto, NZ tuning. ( dont use US tuning as the AM radio will not work properly, 10KHz steps instead on 9 KHz )

Not all units can do this but worth a try.

Band expanders are usually poor quality. and as someone said before you cant fit 20MHz into 14 Mhz

I know enough to be dangerous

Goosey

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#798719 13-Apr-2013 10:16

There's an old guy in the south island who makes band expanders to suit different kHz steps.... I will try to find the website name or simply google nz band expanders.... I think there's also a guy in hawkes bay.