Old Satellite Dishes work good. 8 foot is great, but not very practical. However the 3 foot ones are pretty good, but most of them do not have a 90 degree recieve path, so it requires some getting used to.
Additionally, putting a second Small Parabolic behind the mic is also a good idea.
Dynamic or Condensor Mic's give a good response. Pizo Mic's are Tinny Sounding.
An Amplifier with some Active Filters is useful. Bandpass, Low Pass and High Pass, to reject unwanted noises.
I have built many of these devices and can possibly give you further info, if needed. Just e-mail me.
Take care..........Gary