Chireix- Mesny Directional Antenna
may be used for operation on 145 MHz.
designs of the antenna is presented here. The antenna has wide
passband, high gain, not critical to installation and nearest
environment. Chireix- Mesny
antenna has input impedance 200 Ohm so it is possible match the
antenna with 50- Ohm coaxial cable with help of 4:1 transformer.
Classical example of the 200/50- Ohm transformer made on coaxial
cable shown in:
you may find lots design of such transformer in the internet.
Figure 1 shows
design of the antenna. Reflector wire (30 each) has length in
1302 mm. Side of the rhomb has length in 920 mm. Length of the
rhomb is 1400 mm. Distance between reflector and rhomb is 340
mm. The antenna has wide pass band.
So it is not a strictly demands to keep the sizes as shown in
It is possible to bridge four such antennas to feed
the system with 50- Ohm coaxial cable. In this case DD of the
system would be narrow compare to one element antenna. Antenna
may be made from almost any stuff, copper, aluminum or stainless
wire in diameter of 3- 10 mm. You may play with model to see how
the parameters will be changed depends on the used stuff.
2 shows Z of the UR0GT Chireix- Mesny Directional Antenna for the 145- MHz. Figure
3 shows SWR of the UR0GT Chireix- Mesny Directional Antenna for the 145- MHz. Figure
4 shows DD of the UR0GT Chireix- Mesny Directional Antenna for the 145- MHz.
73 Nick, UR0GT