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TopBand: Re: Pennant Antenna

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Subject: TopBand: Re: Pennant Antenna
From: (Earl W Cunningham)
Date: Thu, 30 Jul 1998 22:42:43 EDT
A number of queries about the Pennant antenna were received, so I'll try
to explain it a little better.

First, nothing goes to ground.  The entire antenna is above ground.  If
the top of the 14' vertical portion of the Pennant is 20' high, then the
bottom of it would be 6' high.

The point of the Pennant is 29' away from the vertical portion, 13' high.
 This means the bottom wire slopes upward from the bottom of the vertical
section and the top wire slopes downward from the top of the vertical
section.  The two sloping wires meet at a point 29' away, 13' high. 
Therefore, via Pythagoras, the length of the sloping sections are 29' 10"
each.  This gives a total wire requirement of (29' 10'' x 2) + 14' = 73'

The 900-ohm termination resistor is in series with this triangular-shaped
antenna, either in the center of the vertical portion, or at the point of
the Pennant. The feedpoint is exactly halfway around the antenna from the
resistor.  Directivity is in the direction of the feepoint end of the
antenna, just like the Ewe (and opposite to the Beverage). 

The directional pattern of the Pennant is identical to the Ewe
(cardioid).  A major drawback to the Ewe is its extreme sensitivity to
any change in the local soil conductivity, i.e., large differences in
antenna size and termination resistance value for an optimum Ewe over
different types of soil.  This shortcoming of the Ewe was the primary
reason the Pennant was developed.  The Pennant is very insensitive to the
soil conditions as well as height above ground.

The antenna size and termination value were determined experimentally
using antenna modeling software to yield a receiving antenna that would
have zero reactance and good directivity on 160m.

Feedpoint Z of the antenna is about 900 + J0 ohms on 160m.

A fringe benefit is that the antenna is a very good as a directional
receiving antenna on 80m and 40m also.

Two Pennants, erected point-to-point, with their feedpoints at the points
of the Pennant, may be used as a switchable-direction receiving antenna. 
K6NDV does this and reports good results.  If you do this, ensure that
you switch both sides of the feedpoint to totally isolate the inactive
Pennant, otherwise directivity of the active Pennant will badly

I hope this answers any questions about the Pennant.

73, de Earl, K6SE

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