[Elecraft] KX1 and EFHW antenna

[Don Wilhelm]

  Sante,

I would suggest that you do a trial run with the antenna at home - use 
an antenna analyzer for this initial tuning.  Once you have found the 
right L and C for resonance, remove the variable capacitor, measure it 
and substitute a fixed capacitor, there should be no need for further 
tuning of that circuit in the field.
Once in the field, some small additional tuning may be required, but the 
internal tuner in the KX1 should take care of that.

Take note that a reduced radiator length version of this antenna is 
shown on page 9 of the KXAT1 manual - with no external tuning unit.  The 
W3EDP radiator wire is close to that 23 feet plus an added half 
wavelength on 40 meters, so for 40/30 and 20, this same length wire 
should behave about the same as the antenna lengths for which the KX1 
tuner was optimized.

73,
Don W3FPR

On 7/11/2011 1:56 PM, Sante - IK0HBN wrote:
> Hi Don,
> thanks for support,
> I'll try to guess how much inductance the coil of W3EDP is, so to use
> a smaller toroid instead of a more invasive and bigger 2 inches coil...
>
> Finally, all I need is (if possible) a single wire antenna for 80-20
> meter range, so to not have to change wire every time I will change a
> band. Even with somewhat like a tuner could do fine, but also with
> something to check the SWR with KX1.
> I know the little jewelty shows the SWR, but only after having tuned
> a wire, so using an external tuner without SWR reading should be
> quite difficult to prune a tuner not having an istantaneus reading of
> what I am going to do.
> Thanks for now
> Ciao
> Sante
>
>