how old is it? Almost every new radio out is either XM or Sirius ready, old ones aren't. Ones that use AUX in and are a direct connect to the radio operate on a seperate antenna and effectively cut off the radio when XM or Sirius is on. FM Mod uses the radio's station and does lose some of the frequency range and can also get interference by a strong signal on that station. It is better for SQ to go with the direct connected ones but the FM mod ones do give the portable ability so you can have a ton of different bases with only one receiver and subscription.