Mad Maxx previously posted:
"Side Tangent: Why isn't MURS used more instead of FRS/GMRS?
Its 2W power limit puts it at the some power as FRS, but given its lower frequency compared to FRS, you can get more range, and you don't need a license like you would with GMRS. You can even use an external antenna."
Because physics (electromagnetics, wave propagation).
MURS is ~ 150 MHz? GMRS / FRS is 450 MHz. The wavelength of MURS is 3x that of GMRS. The MURS radio has a 2 meter wavelength. This means your standard vehicle is a Faraday cage for that wavelength and your performance will be terrible, better than a handheld CB with a rubber-duck antenna but still not good. GMRS/FRS has a wavelength of 2/3 meter, meaning the waves can pass through most or all of the glass openings in a standard vehicle.
If you have an antenna outside the vehicle, none of this is a particular concern. If you try to use a handheld with an attached fixed antenna in a vehicle, this is a big concern.