• Yagi Antenna

The Yagi antenna is best suited for reception in a specific band. This antenna features excellent directivity; it provides high gain and minimizes interference when properly installed. Yagi antennas commercially available are designed only for HAM band reception. For SW reception, it will be necessary for you to construct such antennas your-

• Wideband Antennas

Discone and log-periodic antennas can cover a wide frequency range. The discone antenna is omnidirectional and has a widerange from VHF to UHF. (See Fig.7-7)

Note:

Antennas designed for HAM BAND will generally provide satisfactory reception for SW stations near the HAM BANDS. For antenna construction details, see the ARRL ANTENNA HANDBOOK, or similar publications.

7-2-2. Grounding

Normally, the receiver will operate without being ground- ed. However, a good earth ground improves the efficiency of antennas such as a long-wire. It also eliminates inductive noise and protects the operator from electric shocks through the AC lines.

To ground the receiver, use a copper or brass plate (or net or rod) connected to a copper wire, and bury it in the ground about 1 , 7 feet (0.3 ~ 2 m) deep. A copper water pipe (not plastic) may also be used. Never use a gas pipe for grounding.

If the receiver cannot be grounded well, the conterpoise (antenna radial) would be acceptable.

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