Hunting down rogue high powered 433Mhz transmitter?

[Melt-O-Tronic]

This should suit your needs easily:
http://www.instructables.com/id/433-MHz-tape-measure-antenna-suits-UHF-transmitte/step4/Alternative-DIY-UHF-Yagi/

[james_s]

The Oregon Scientific protocol has been reverse engineered and documented, I was able to receive and decode it with mine. Last I checked though the development of rtl_433 seemed to have stalled.

The RTL dongle works great as a police/emergency services scanner, it will also pick up the business band, FRS radios, baby monitors, fast food drive through intercoms and internal coms, pager signals, those aren't nearly as common anymore but doctors still use them. All sorts of interesting stuff flying around in the air.