I second a cup holder mount. With anything like that (handheld, etc.) it is best to keep it down low and not up at face level. In the event of an accident, anything not bolted down can and likely will become a flying object that can inflict injury to the driver or passengers that otherwise wouldn't have happened.
You can always use an external antenna for better reception, if needed, but mounting it up on the dash or at head level is not advised.
There may be someone who comes along and says that theirs is up on the dash and does fine but, again, that isn't advised as it is a danger in an accident. Mount it low and as securely as possible.
Lidomounts has some cup holder style mounts that might work.