Can't speak to whether the N900 supports this frequency, but I figured I'd put my radio nerd hat on for a minute. There are two reasons why there are basically no licensed radio stations at 87.9 FM:

1) The treaties the US has with Canada and Mexico only cover the frequencies from 88.1 MHz through 107.9 MHz. The FCC has the actual documents at http://www.fcc.gov/ib/sand/agree/fil...-bc/can-fm.pdf and http://www.fcc.gov/ib/sand/agree/files/mex-bc/fmbc.pdf. Any station within 320 km of either border has to abide by these agreements and can't be on 87.9, so that rules out large swathes of the northern and southern portions of the US.

2) The other reason has to do with the old analog VHF TV channel 6. The audio for channel 6 was broadcast at 87.75 MHz using the exact same transmission technique as broadcast radio. Since each FM station needs 0.1 MHz of space on each side of its center frequency, channel 6 (which would extend to 87.85 MHz upwards) rules out a radio station at 87.9 (which would extend to 87.8 MHz downwards). So anywhere there was a channel 6 TV station, 87.9 MHz couldn't be allocated.

Interesting tidbit: Wikipedia claims (http://en.wikipedia.org/wiki/FM_broa..._United_States) that there are in fact only *two* licensed radio stations in the whole country on 87.9MHz: KSFH Mountain View, CA (a high school station) and K200AA Sun Valley, NV (a translator of Christian radio station KAWZ Twin Falls, ID).

And there's your bit of radio trivia for the day (or month!). Now back to our regularly scheduled programming, also known as "wishing I could buy an N900"...