[Elecraft] KAT2 with EFHW antenna

[David Gilbert]

Yup ... I was wrong again, but the trouble is I can't figure out why.  I 
mean, it's easy to verify the cloverleaf pattern with EZNEC and I have 
done so, but I know that I have modeled something similar with an 
off-center feed in the past and gotten an end-fire pattern.  As soon as 
I figure out what that was I'll come back here and try to clear up the 
confusion I have caused, but in the meantime let's all just agree that I 
don't know what I'm talking about.

sigh ...

73,
Dave   AB7E




On 8/25/2011 11:13 AM, Guy Olinger K2AV wrote:
> Sorry to interject, but a fullwave fed at the 25% point has a clover 
> leaf pattern.  It only has the two halfwaves in phase colinear 
> behavior when fed very near the center. Even fed at 45% it has a 
> significant cloverleaf lobe and a NULL in the center  Easy to verify 
> with any modeling program.  73, Guy.
>
> On Wed, Aug 24, 2011 at 8:37 PM, David Gilbert 
> <xdavid at cis-broadband.com <mailto:xdavid at cis-broadband.com>> wrote:
>
>
>     Yes, Don ... you are totally correct.  For some reason I was thinking
>     about a full wave antenna fed at the 25% point (I have built such
>     antennas before), which looks like two colinear half waves fed out of
>     phase.  The current phasing along the antenna would indeed be much
>     different and give a cloverleaf pattern if it were end fed.  I
>     wholeheartedly apologize for any confusion I may have created.
>
>     73 and thanks for catching my mistake.
>
>     Dave   AB7E
>
>
>     On 8/24/2011 3:23 PM, Don Wilhelm wrote:
>     > Actually Dave, a full wavelength wire will have a " 4 leaf clover"
>     > pattern - that is neither broadside to the antenna, nor off the
>     ends.
>     > Check out the pattern for a 1 wavelength long wire in the ARRL
>     Antenna
>     > Book.  The maximum radiation is about 28 degrees from the wire - the
>     > radiation from the end is almost zero.
>     >
>     > The elevation angle of maximum radiation is similar to a half wave
>     > dipole - about 15 degrees with a lesser lobe at 45 degrees (that is
>     > for a wire 70 feet high, at lower heights, the angle will be
>     greater).
>     >
>     > 73,
>     > Don W3FPR
>     >
>     > On 8/24/2011 5:34 PM, David Gilbert wrote:
>     >>
>     >> I'm not sure I see the advantage.  A full wave end fed antenna
>     would
>     >> theoretically have the same very high feedpoint impedance, and
>     would
>     >> additionally blow most of it's radiated energy at a fairly high
>     angle
>     >> off the ends of the antenna instead of broadside at a lower
>     angle.  If
>     >> you find it that easy to tune, I suspect that electrically it
>     really
>     >> isn't that close to a full wavelength ... possibly because of
>     coupling
>     >> to earth (if it is low) or nearby structures.  Either that or
>     there is a
>     >> lot of loss in the system somewhere.
>     >>
>     >> 73,
>     >> Dave   AB7E
>     >>
>     >
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