The Gray Hoverman design is based on the Hoverman patents but we are waaaaay past that into a range of performance that beats any comparable commercial antenna (the SBGH smokes the CM4221, the DBGH smokes the CM4228) and any other DIY antenna project of similar requirements.
Notes: * CM4228 is the original Channel Master 8-bay bowtie reflector (data from HDTVPrimer) * CM4228HD is the new Channel Master 8-bay bowtie reflector * PR-8800 is made by Winegard (data from HDTVPrimer) * DB-8 is made by Antennas Direct (data from HDTVPrimer) * GH10 is a Single Bay Gray Hoverman Gold Standard (data from j3d) * DBGH is a Double Bay Gray Hoverman (data from 300ohm) * * is for Channel 51 (antenna not designed for 52 and higher)
The announcement I made earlier today is about a new variant of the SBGH and DBGH antennas that also get great VHF-HI gain. It isn't on this table.