ANTENTOP- 01- 2010, # 012

Directional Helical Antennas

Table 1 Data for testing of the Helical Antenna

Column "S- Meter" shows normalized level- Helical Antenna/WINDOM. For example, digit "2" shows that level from the Helical Antenna is in 2 times more (according to the S- meter of the receiver) compare the level from the WINDOM

Figure 5 shows the design of the Four- Wire Line. The Four- Wire Line was placed onto insulators under the square wood stick. The Small Directional Dipole Helical The small sized Antenna at the test showed that this one worked similar to the helical antenna shown on the Figure 1.

It was tested Directional Dipole Helical Antenna with reduced sizes. Length between the Helical Dipoles was lambda/8, or 2.6-m for the 20- Meters Band. However there was used Four- Wire Open Line between the Dipoles. Figure 4 shows the design of the Small Directional Dipole Helical Antenna.

However, the Small Directional Dipole Helical Antenna was more complicated in the tuning compare to Antenna from the Figure 1. The antennas were fed by 500- Ohm two- wire line with length 15.6-m (3/4- Lambda).

Figure 4 Design of the Small Directional Dipole Helical Antenna

The antennas were fed by 500- Ohm two- wire line with length 15.6-m (3/4- Lambda).

Tuning of the Directional Dipole Helical Antenna (for both antennas- Figure 1 and Figure 4):

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