[TowerTalk] Wire antenna?

[Richard (Rick) Karlquist]

You're right; my bad.  I actually had an end fed full
wave on 40 meters 30 years ago and used to know this :-).
40 meters was a "free bonus" feature of my 80 meter half wave.
The cloverleaf pattern wasn't optimum but it did make
QSO's etc.  It was a cloud burner at 55 feet anyway, so
it was never going to be anything great.  The 4 nulls tend
to fill in at low heights.

This just reinforces the notion that the
EFHW should be considered a single band antenna, on
the frequency where the wire length produces half
wave resonance, as indicated by a high resistive
drive impedance.  This will be a few percent less
than a half wave in free space.

For higher frequencies, the "magic" goes away and
it becomes a glorified "random wire" requiring a legitimate
counterpoise.

Random wires (> 1/2 wave) have random patterns!

Rick N6RK

On 7/1/2019 9:27 PM, K9MA wrote:
> On 7/1/2019 22:24, Richard (Rick) Karlquist wrote:
>> On the frequency of full wave resonance,
>> they still make sense because they are two half waves in phase
>> and behave similarly to a half wave dipole.
> 
> For an end fed wire, this is not true. Its pattern has 4 lobes, a 
> cloverleaf. It is like a full wave fed 1/4 wave from one end. That's two 
> half waves OUT of phase. A center fed full wave is indeed two half waves 
> in phase, and has the dipole-like pattern, a bit sharper, with a bit of 
> gain over a dipole, and a very high feedpoint impedance.
> 
> Because of the cloverleaf pattern, an end fed full wave can be quite 
> useful. At higher harmonics, the lobes proliferate, and tend to get 
> concentrated towards the axis of the wire, which is often less effective.
> 
> 73,
> 
> Scott K9MA
>