ANTENTOP- 01- 2016 # 020

Memorandum on the Beverage Wave Antenna

The system of changing directivity of the antennas and remote erasure adjustments as outlined is somewhat inconvenient because of required travel, terrain condition, time consumption and the fact that the antenna when made directive in one direction is not available for service in the opposite direction.

To overcome these undesirable features, a modified arrangement of the terminal coupling units and rejection system may be employed which permits the use of a two-conductor wave antenna for unidirectional reception both forward and rear simultaneously on the same or different frequencies with the band for which the antennas are designed, and with all variable factors under control at the receiver.  The circuit is shown in Figure 6.

Two Conductors for Simultaneous Forward and Rear Unidirectional Reception

 The signals are delivered from the near antenna terminal coupling transformers to a terminal rack through two 400-ohm transmission lines connected to a Graybar #223-A, three-point, switchboard jack.  The receiver input lead connects to the terminating jack through a short length of good quality lamp cord and a Graybar 3-A phone cord plug.  A fixed one-watt resistance unit of proper value is connected across points 1 and 2 of the Graybar jack which automatically connects across the transmission lines when the receiver plug is out.

INTER-ANTENNA COUPLING

 In the event the erection of more than one wave antenna may be contemplated, the question of inter-coupling may arise.

Tests covering this feature at Grand Island using a standard signal generator indicated that broadcast band wave antennas may be crossed within a few feet of one another at angles of sixty degrees or more without detrimental coupling effects or may be safely paralleled when spaced four hundred feet or more; in either case without noticeable or excess coupling.

When the antenna conductors run parallel over wire fences with non-conducting supports, the fence wires, to avoid interaction, should be broken with insulators at even lengths of about seventy-five feet.
   

Conductors such as fence wires and metal posts rubbing against one another within a hundred feet or so of the antenna may be assumed to be a source of noise generation in the antennas.

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