ANTENTOP- 01- 2006, # 008

Field Antenna for the 40- meters

Figure 5 Base of the antenna

Note by VA3ZNW: MMANA does not provide correct simulation when elements of the antenna aerial are located close to the ground. NEC- 2 for MMANA should be used in the situation. So by me the antenna was simulated in NEC- 2 for MMANA.

Figure 7 shows the diagram directivity and data for the antenna. Input impedance is near 21 Ohm, capacitor should be had 132-pF. For matching the antenna with 50-Ohm coaxial cable an inductor 0.9 micro Henry should be turn on across antenna clips, and base capacitor C should be used on to 100-pF. Off course, the real capacity should be found at tuning of the antenna.

Figure 8 shows the circuit of this matching device.

Figure 9 shows parameters of the antenna depending on ground, above which the antenna is located. As you can see, the ground does not influence much to the parameters of the antenna. So, the antenna can be placed above any ground.

11. Average (Eps=13, Sigma=5)

12. Poor (Eps=13, Sigma=2)

13. Pastoral (Eps=13, Sigma=6)

14. Marshy land (Eps=12, Sigma=7.5)

15. Pastoral rich (Eps=14, Sigma=10)

16. Very good (Eps=20, Sigma=30)

Figure 6 Wire and guys of the antenna at mast

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