I am wondering if its possible to expand the range of FM frequencies the N900 can receive. The US version FM receiver can tune approximately 87.5 MHz to 108 MHz.

What if you wanted to receive on frequencies below 87.5 MHz or above 108 MHz? I realize there is not much to listen to below or above the FM band, but directly above the FM band is the Air-traffic Controller frequencies (although they use AM modulation, not FM modulation which is what's used for standard FM radio). Any cheap RadioShack scanner can legally pick up these frequencies. I wonder if there is a file we can edit to change the receiving range of the FM tuner.

Does anyone have any thoughts on how this would be done?

I assume the antenna and tuner are probably limited in hardware to a specific frequency range. This range may or may not include a slight margin above and below the common frequencies. I assume that it does though, since other countries use slightly different frequencies. As far as the demodulation, it is likely done in hardware since it is fast and easy to do, therefore I doubt that you would be able to interpret the AM signals even if you could receive them. This is all guesses, and I dont know the specifics about the hardware or software. But this is my field.

There is a bug at bugzilla for this . So if you could help to vote for the bug, then maybe nokia will make it as a priority to fix this. It looks like its only a problem with software :-).

You bring up very good points. I do think it would be neat to tune outside of the regular FM radio band. Imagine if we could get the N900 working like a VHF/UHF scanner... of course then we'd need to figure out how to get some "squelch" in order to not get white noise when there is no signal...

Or, better yet, imagine getting the N900 to tune shortwave (2 MHz - 28 MHz)... then you could really call this device a "world" device since it would pick up shortwave broadcasts from all over the world... but that is highly highly unlikely, at least without hardware modifications. We don't have AM modulation, or USB (Upper Side Band) or LSB (Lower Side Band) which is required for shortware (HF) communication listening. If anyone on the board if an amateur radio operator (ham radio) they will know what I'm referring to.

Oh well, we can only dream on...

It should be possible to get lower frequencies then 87.5Mhz because that works in Japan!

Have you got the bug number? I couldn't find it in a quick search.

Please see this Thread: FM Transmitter Mod (a possible solution at Post #34)

Edit: Oh, sorry. My fault. You're asking for receiver. Not transmitter. I'm sorry.

What is the receiving frequency range of FM on the N900 in Japan?

Is that possible expand frequency to 433,92 MHz and use as RF remote controller like this: http://www.johdoton.fi/tuotteet/yct-100 ?

I need it everyday and it would be great to use mobile phone for it.