[Hallicrafters] inverted V

[Brent Seres]

Bill Gerhold wrote:

>An inverted "V" is not as efficient as a horizontal dipole for the following
>reason.
>
>Signal cancellation!  Cancellation of the signal due to the legs of the "V"
>not positioned 180 degrees from each other.  Try this thought experiment.
>
>Start to move the end points of the "V" together closer and closer until
>they are about 2" apart.  What do you have? A reasonable resemblance of
>parallel feeders or a transmission line.
>
>In an inverted "V", and depending on the proximity of each leg to the other
>including the frequency of operation (HF), there will be a certain amount of
>signal cancellation due to currents in the opposite legs being 180 degrees
>out of phase.  A parallel feeder transmission line has almost 100%
>cancellation in the HF region.
>
>This is why parallel feeders or a balanced line does not radiate when
>connected to a balanced antenna, a dipole.  A dipole is simply a parallel
>feeder physically split 180 degrees from each other.  Since both legs are no
>longer next to each other to provide cancellation, signal radiation occurs
>from your dipole.  There is zero cancellation.
>
>There are many articles that quote the no less than 90 degree separation.
>Why?  Because less then this, cancellation of the signal starts to become a
>problem and your signal starts to suffer.  You must ask yourself, if 90
>degrees is a minimum, wouldn't 180 degrees be better?  It is!
>
>An inverted "V" because of its construction (the legs closer to each other),
>still has a certain amount of signal cancellation whereas a true dipole or
>flat top does not.  Therefore, an inverted "V" is not as efficient as a flat
>top but the difference is probably too small to be noticed on a distant
>receiver.
>
>K2WH
>
>  
>
>Remember too, 3dB is barely discernable
>  
>

Brent

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