[Antennas] Question

[Dan Richardson]

At 09:16 AM 8/2/2003 -0400, n8csp wrote:
>[snip]
>
>It's as if people don't  believe they work - ha.  For DX the vertical, if
>mounted close to ground, has about a 7 degree take off angle, which is very
>beneficial to long distance communications.

Almost - if it mounted over salt water. For salt water NEC modeling=20
indicates that maximum take off angle is 10=BA.  When mounted over average=
=20
ground the takeoff angle rises to 27=BA. You can easily check this yourself=
=20
using NEC.

[snip]

>Besides, verticals can also exhibit as much as 6 dB GAIN over a
>dipole (dBd)

NEC reports the maximum gain for a =BC-wave vertical (using 12 radials)=20
mounded over average ground to be 0.57 dBi at 27=BA and a =BD-wave dipole @=
 65=20
ft above average ground produces 7.01 at the same (27=BA) angle. BTW: The=20
dipole's maximum gain is 7.1 dBi @ 30=BA.

Note: Adding additional radials will increase a vertical's gain but to the=
=20
extent that it will come close to equaling the gain of a =BD-wave dipole.=20
Additionally, adding radials does not lower a vertical's takeoff angle -=20
that is determined by the ground properties up to several wavelengths from=
=20
the antenna.

Your suggestion that a vertical be considered is a valid one, but don't=20
expect the antenna to have more gain or perform better than a properly=20
installed dipole.

73
Danny, K6MHE