> Firstly, why is the choice between no function or a crappy function? Why would every FM radio app necessarily be crappy?
FM antenna has to be quite big no? My old Cowon media player needed to have the headphones plugged in in order to use the FM function. That would mean that people with Bluetooth headphones (an ever increasing number) are out of luck.
> Thirdly, why does the hardware have an FM receiver at all if I can't use it?
Because the receiver is part of a standard package shipped by Qualcomm and it is probably cheaper to leave it in. What the device does not have is an antenna and an amplifier for the signal (as mentioned in other comments)
No. Here's some food for thought: The wavelengths used for cellular communications in the order of about 0.3m to 0.4m for a lambda/2 dipole that would be an antenna length of 0.15m to 0.2m, which is quite larger than your typical phone.
There's no rubber hose dangling out of modern phones (it used to, 20 years ago), so what's the deal here? Impedance matching,coupling efficiency and planar antenna array designs are. Technically any power of 2 fraction of a given wavelength can be used for an antenna for that wavelength, if assuming an simple wire antenna. But the higher the order, the higher the impedance and the lower the coupling efficiency. With a clever choice of dielectrics the coupling efficiency can be brought back again into manageable regions. And thanks to numerical field simulations we can now design small antenna shapes that can work on much larger wavelengths.
FM radio is receive only, so you do not even require very good coupling efficiency, because you don't have to deal with TX reflection backlash. Hence the problem boils down to designing a reasonably small patch antenna for the 3m band and a receiver circuit that can deal with the high impedance and low coupling efficiency. Back in the day of radios made from discrete components that would have been prohibitively expensive, but these days you can throw a couple hundred of components at some unused corner of your RF grade semiconductor die and have dealt with it.
FM antenna has to be quite big no? My old Cowon media player needed to have the headphones plugged in in order to use the FM function. That would mean that people with Bluetooth headphones (an ever increasing number) are out of luck.
> Thirdly, why does the hardware have an FM receiver at all if I can't use it?
Because the receiver is part of a standard package shipped by Qualcomm and it is probably cheaper to leave it in. What the device does not have is an antenna and an amplifier for the signal (as mentioned in other comments)