> -----Original Message----- > From: [email protected] [mailto:Repeater- > [EMAIL PROTECTED] On Behalf Of Laryn Lohman > Sent: Tuesday, February 20, 2007 5:59 PM > To: [email protected] > Subject: [Repeater-Builder] Re: Antenna gain specs > > --- In [email protected], "Steven Samuel Bosshard > \(NU5D\)" <[EMAIL PROTECTED]> wrote: > > > > What I don't understand is how at times the DB224 is rated at 4.5 > dBd, then 6 dBd, > > Hmmmm.... that's a new one. Where/when and what frequency range have > you seen the DB224 rated at 4.5dbd? > > > > and the DB304 (twice as much aluminum) rated at 6.1 dBd. over a > span of 30 years...de nu5d > > Omnidirectional gain is achieved by vertically stacking more "levels", > if you will. Doing what they've done with the DB304 does not add more > levels. So no more gain. > > To be honest, I'm not sure what the reason is for the double dipole > arrangement. I suspect it electrically makes the mast <disappear> > since each pair is symmetrical with the mast. Someone else I'm sure > has a better explanation of this design. > > Laryn K8TVZ >
When you look at the antenna patterns in the catalogs they look like nice smooth circles for the gain pattern. This is far from realistic as most antennas will have many many peaks and nulls in the pattern. What the diagram in the catalogs try to show is an average gain pattern. The addition of more elements on the same level in antennas such as the DB304 will "fill" in more of those peaks and nulls to make a better more consistent pattern. They can also be used to make the antenna more broad band. 73 Gary K4FMX
