OET63 has a very useful table for figuring out where part 15 broadcasts can happen. https://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
The table starts on page 9 of the document (page 12 of the PDF). In the type of use column, if it says any, then continuous transmitting of audio/video/data could be done there.
If someone wanted to transmit 80kHz wide FM, (or some sort of AM) between 49.82MHz and 49.9MHz, they could with a field strength of 10,000uV/m at 3m if they were using a certified transmitter. 15.235(c) gives limits for a home built transmitter for that range. Operating in that band would require the person listening to have something such as a scanner, but the range could be good.
to Rich and stvcmty for getting this right and boo to me for getting it wrong. Things can be confusing and we need to read the rules very carefully.
Neil
Maybe in your FM initiative to present to the FCC this can be mentioned and maybe 87.9 or 87.7 can be available to hobby radio.
Mark
Here is FCC consumer information regarding Part 15 unlicensed wireless mics brought to us by Shure Microphones:
http://www.shure.com/americas/support/spectrum-topics/fcc-alert
According to the ** note in FCC §15.209(a), a carrier frequency (fundamental emission) "shall not be located" in the TV broadcast bands either below or above the 88-108 MHz FM broadcast band.
The reference in §15.239(c) to fields at frequencies greater than +/-100 kHz from the carrier frequency requires compliance with §15.209 -- and §15.209 does not permit the use of carrier frequencies outside the 88-108 MHz band.
That would eliminate the legal use of a carrier frequency of 87.9 MHz, and many channels below.