ANTENTOP- 01- 2016 # 020

Memorandum on the Beverage Wave Antenna

 The signal builds up until it reaches B where the phase is reversed by grounding one of the conductors and leaving the other free after which it is reflected back to T using the antenna conductors as an untransposed transmission line.  The signals from B direction are dissipated either completely or partially in impedance R connected from the center tap of T to ground.  It will be noted that Figures 2 and 3 are the same except with respect to far and near terminal connections.  When it is changed as shown, the antenna can be made unidirectional for either forward or rear reception, but not for both forward and rear reception simultaneously.

When the wave length of the signal to be rejected is a multiple of one-half wave of the length of the antenna, it is either completely or largely absorbed in resistances Rb or Ra. 

Odd multiple frequencies of one-quarter wave length of the antenna length deliver a greater residual or undesired signal to the receiver.

In order to balance out an undesired signal originating at an angle of more than ninety degrees from the source of a desired signal originating in direction of maximum reception of the antenna, part of the undesired signal is reflected back to T in proper phase and magnitude to cancel itself out.  This is accomplished by the insertion of a tuned circuit in series with a variable resistor at the far terminal, as in Figure 4 for rear signal rejection, and as in Figure 5 for forward signal rejection.

Two Conductors for Forward Reception

Two Conductors for Rear Reception with Rejector Circuit

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