[Elecraft] KX1 # 2047 comes alive!

[Don Wilhelm]

Sante,

Although you may be able to load a small antenna on 80 meters, the 
efficiency will diminish as the antenna gets physically smaller (one 
cannot defeat the laws of physics).
I would suggest that you carry along extensions.that you can clip on to 
extend the physical length of your radiator to something in the vicinity 
of 135 feet total (radiator plus "counterpoise").

Whether the extensions are deployed at height or simply strung out near 
the ground will not make much difference - keep the antenna center high 
because that is where the major portion of the radiation takes place.

Picture a half wave dipole with the center of that half wave at the 
highest point you can manage.  That dipole can be fed at the end, the 
center, or any point in between with the feedpoint impedance varying 
from about 50 to 75 ohms (for center fed) to 4000 ohms (for end fed) - 
you must choose the 'best' arrangement for you depending on what you 
anticipate your portable physical constraints might be (horizontal 
space, vertical space, etc.).  Consider a vertical radiator as half a 
dipole - you need radials to complete the dipole - if the radials are 
physically opposing, the horizontal radiation will cancel and all the 
radiation will be only vertically polarized - a single radial will 
result in both vertical and horizontal radiation - either will work, but 
the distance covered will vary depending on propagation conditions 
existing at the time.

73,
Don W3FPR


Sante - IK0HBN wrote:
> Hi everybody,
> I just finished to assemble my KX1 with autotuner and 30/80 option and 
> I have one question for you:
> "As the the manual has been written for 20-30 and 40 meters bands, the 
> lenghts for a long wire are given for those bands. How long should it 
> be for having a good compromise even on 80 mtrs? I'd like to have just 
> one wire for backpacking"
>
> Thanks in advance
> Sante, IK0HBN
>