Use my homepod to hear audio at the drive-in theatre through FM

I would like to use my homepod to hear audio at the drive=in theatre. The drive-in theatre uses a local fm transmitter that broadcasts locally within a 500 foot range or so. Is there a way to enable my phone to receive this signal? The drive-in does not broadcast over WIFI so it seems the FM apps on the iphone won’t work. Or is there another portable device (fm receiver) that would allow me to receive the signal and then transmit it either by wire or wirelessly to the homepod? I can’t seem to find one that will send output wired or wirelessly to another device.