> -----Original Message----- > From: Repeater-Builder@yahoogroups.com [mailto:Repeater- > [EMAIL PROTECTED] On Behalf Of Jim B. > Sent: Monday, February 19, 2007 4:32 PM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] Re: Antennas that work both in commercial > and amateur > > >> Right-slightly OT, for a mobile antenna, you will find that you can > >> squeak out a bit more gain by using a .64-wavelength whip instead of a > >> pure 5/8-wave (.625) > >> In the late 60's/early 70's, the NewTronics BBL series VHF gain > antennas > >> were rated at an honest 4dB gain-and did it. The A/S VHF gain antennas > >> measured about 2 dB. They were actually end-fed 1/2-waves... > >> If you can find an original BBL-144 still in good shape after 30+ > years, > >> keep it! > >> -- > >> Jim Barbour > >> WD8CHL > >> > > > > Are you telling us that the difference in length between .64 wavelength > and > > .625 wave length, a mere .015 (about 1.2 inches)amount, accounts for a > full > > db of gain? > > End result: 4dB gain over a 1/4-wave (should've specified that part). > Not sure whether it was a full dB over a 5/8-but that was the peak in > the gain curve. > > > How do you know they provided 4 db of gain? > > > > 73 > > Gary K4FMX > > Measured on their range-they used to be based in Cleveland, and my > father was one of the designers. > (anybody here remember the PRO-27JR 27Mhz antenna? Or the original 4BTV?) > -- > Jim Barbour > WD8CHL >
With all due respect to your father Jim, I think that 4 db of gain is wishful thinking. A 5/8 wave length antenna theoretically is a little over 3 db and in real life 3 db is seldom realized. If I am not mistaken a .64 wavelength would have at most a tenth of a db advantage over a 5/8 antenna. 73 Gary K4FMX
