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BAND-WIDTH EXPANDER HELP
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Old 23 Oct 2010, 11:55 PM   #1 (permalink)
Young Scooby
 
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BAND-WIDTH EXPANDER HELP

I know this is essentially a Subaru site, so I feel a little cheeky asking a question about my Skyline 350GT, but here goes:-
The Bose radio reception is sh1t, so I took it to a local ICE specialist, who, after having the car all day and breaking a piece off the centre consol ("wasn't me mister, it was already like that"), told me it needed a special dual connection Band-Width Expander and he couldn't get hold of one, (But if I got one from somewhere, he could fit it for me ...........errr, no thanks!).

I have looked for such an item, but I don't know what I'm searching for, yet I would've thought most late Japanese imports would need similar BWEs.

Any information would be much appreciated.
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Old 24 Oct 2010, 10:59 AM   #2 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

I'm perplexed. A "bandwidth expander" doesn't make a lot of sense without a lot of active signal processing (and how do you put back the information that you lost when the bandwidth was shrunk? Surely that's been lost...). Frankly it sounds as much BS as the "I didn't break this".

What is the actual issue? Radio reception as in noise/not latching on to the radio station when moving? Or as in sound quality?

If it's the former, I'd say a good look at the aerial cables and possibly an aerial amplifier should do the trick. Nothing to do with your car being a Japanese import or otherwise.

If it is sound quality, it is possible that some of the FM de-emphasis circuitry is built around the Japanese standards of broadcast, which may be different from the UK ones (the difference certainly exists with the US market). Fixing it may be very easy or practically impossible depending on how the EQ circuit is built, but it does require a circuit scheme and the willingness to tamper with the innards of the radio. Adding after-market boxes in between the current components (if they are indeed separate eg tuner/CD/pre and final amps) is not really going to work.

The last option, of course, is that the sound quality is crappy regardless of the source - and that may be indeed the case. Serious after-market ICE components tend to cure that, but they cost and some of the parts may require modding (think door or facia panels) to fit the new components.

Last edited by oldmancoyote; 24 Oct 2010 at 11:19 AM. Reason: Added material
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Old 24 Oct 2010, 11:48 PM   #3 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

Hi Oldmancoyote, and thanks for your reply.
I'm not very clued in on the reasons for the bandwidth expander, all I know is that when I bought the car, the seller told me that he'd had one fitted because the Japanese frequency range is smaller than in the UK (the radio only reads from something like 76 to 89 on FM).
The choice of stations has always been small and reception poor, and often I have to change to alternative frequencies when on the move, where in other cars I don't.
The sound is fine once it has good enough reception, but the reception did get worse a while back and that's when I took it to the "ICE specialist". He said that the Bandwidth expander wasn't the correct one as it needed to have dual ariel connections and had been cobbled to work. He improved the connection and the reception was back to how it was originally, so it wasn't all a waste of time.
You seem to be inferring that a bandwidth expander shouldn't be necessary, but if so, how can the Japanese radio receive outside it's narrow range?
The signal amplifier sounds interesting, how big and expensive are they?
The previous owner did say he knew someone who could adapt the radio properly so that it would be just like a UK one, but at a cost of circa 200 ..........ouch!
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Old 25 Oct 2010, 07:31 PM   #4 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

Basically, it's a frequency expander that attaches between the antenna and the antenna input to the head unit allowing the reception of the higher UK FM frequency band. They are readily available on ebay, or on sites on the net, just search for FM radio frequency expander, most cost around 12. Here's an example www.autolinkmx5.com/radio-band-expander-125-p.asp
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Old 25 Oct 2010, 09:49 PM   #5 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

My fault. When you spoke of bandwidth, I was thinking of audio bandwidth, not broadcast frequency, hence my comments. What Stu is suggesting makes perfect sense, although it sounds like yours isn't a straightforward installation (e.g. dual aerial), plus the FM expander will never get things like the frequency displayed being "right".

If you want that, the only ways are to reprogram the head unit (if it can be done) or replace it with an EU spec one (87.5 - 107.9 MHz).
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Old 26 Oct 2010, 09:37 PM   #6 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

Thank you for your replies again Sumeek and Oldmancoyote.
I have been looking at what frequency expanders are available, ...........MY GOD THERE ARE LOADS!
I have a couple of problems now:-
Which is the best suited for me as there are 10mhz, 12mhz, 14, 16 18 & 20 and all sacrifice a portion of the UK frequency range because they don't really expand it, they shift it by the above stated increments. However, there are many on Ebay that purport to cover from 88-106mhz without stating any frequency shift, and they range from 6 to 12, (funny thing is, they nearly all have the same advertising blurb, word for word), dodgey I think.
How on earth can I tell which is suitable, if any, for my set-up?
I better get back to swatting up, I suppose.
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Old 27 Oct 2010, 08:11 AM   #7 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

I used to have a 12 Mhz Expander fitted to mine before I changed the head unit, this gave 88 -102, which was ok for me, however I've found a link to a site that's selling a full range 12 Mhz expander, with an explanation on how it works, hope this helps. 12 Mhz 'Full Range' FM Band Expander NCS - Systems
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Old 27 Oct 2010, 01:39 PM   #8 (permalink)
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Re: BAND-WIDTH EXPANDER HELP

You can get expanders that use multiples of the shift frequency (e.g. 10 and 20) to cover more bandwidth; you'll still get holes in the coverage and/or duplicated or overlapping stations (e.g. with the tuner on 80 MHz with a 10 MHz expander you'll get stations broadcasting on 90 and 100), not to mention the difficulty in remembering that to tune into say BBC1 on 95.6 you need to go to 85.6 (+10), but to tune into Jazz FM on 102.2 you need to go to 82.2 (+20)!

And Kiss FM on 100.0 is coincident with BBC4 on 90.0, which makes for an interesting mix...

I would still recommend that you change head unit if you do a lot of FM listening.
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