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AMATEUR STATION F

Station F was a relatively complex station with several different antenna systems at various locations on a large residential lot occupied by a single-story residence and a few smaller buildings. A few of these antennas were selected for study during the survey. These included two "inverted V" (sloped) dipole antennas, a "modified T" antenna, and a Yagi antenna with "log-periodic cell" feed.

(1) Modified-T Antenna (160 m)

The "modified-T" antenna was fed by a two wire open line shorted at the transmitter end in the ham shack located inside the house. This wire feed, which was also a radiating element, extended horizontally next to and about 2-3 m above a sidewalk for about 50 m before curving around and turning upward to become the vertical segment of the antenna. The vertical segment was directed up for about 21 m to a point where it met a perpendicular radiator (the top of the "T"). The top of the "T" had a total length of about 41 m. This antenna was used primarily for operating at about 1.9 MHz. However, with the feedline unshorted it can be used as a center fed dipole on 3.8 MHz or as two half- waves in phase at 7.2 MHz. Results of field measurements are given in Tables 18 and 19.

(2) Inverted-V Dipole Antennas (40 m and 80 m)

Two "inverted V" dipole antennas were also studied. The first antenna extended at a slope on both sides of a pole from approximately 14 m high on the pole down to about 6 m above ground at each end. Each segment of the antenna was approximately 10.5 m in length. This resulted in an angle of about 45 degrees. This antenna was operated at 7.2 MHz with a coaxial feed and balun at its apex.

The second "inverted V" dipole extended down at a depression angle with respect to the horizontal of about 60 degrees from a pole approximately 25 m high. Each of the two segments was about 20 m long, and the ends of the segments were about 8 m above ground. Measurements were made when the antenna was transmitting at a frequency of about 3.8 MHz and fed with a coaxial feed and balun at its apex. Results of field measurements for these two antennas are given in Table 20.

(3) Yagi Antenna (2 m)

Another antenna studied was a 13-element, vertically-polarized Yagi with "log-periodic cell" feed via coaxial cable. This antenna was mounted just outside the residence on a tower approximately 6 m high. The boom length of the antenna was about 6.5 m, and the operating frequency used was about 147 MHz. Measurement results are given in Table 21.

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