Simple dual band antenna for 145 - 431 MHz - Pattern study

Pattern study using the software "EZNEC"  V6 free by W7EL

Ideal situation (dipole in free space):

At  145 MHz; this is the classic diagram of an half wave dipole:

At 431 MHz; this is a diagram of a 3/2 lambda dipole in free space:

But if you put the dipole in vertical polarization, 3 meters from the ground you che see this:

For the half wave dipole at 145 MHz:

For the same dipole at 431 MHz:

In both case maximun gain in low in the horizon and, yes this antenna is not for DX, but it is a simple, cheap and usable antenna.

73 de IZ3AYQ

The simplest dual band antenna for 145 and 431 MHz

73 de IZ3AYQ

2 meters quad

2 meters quad Antenna

The antenna can be tuned for 145 or 144 MHz, and used in vertical polarization (as in this picture) or in orizontal polarization. How to tune it? Move the aluminium tube left or right. The tube is insulated
from the quad by two small plastic insulators. It is an indoor antenna or antenna for restricted space.