[Elecraft] RF in the Trees

[Brian Hunt]

Jim's presentation is excellent, covering lots of trade-offs that most 
of us face putting up antennas.  There are a couple (at least) other 
aspects that should be considered.

I've been using an end fed half wave vertical for several years with my 
K1 for portable ops.  It's easy to put up on a 33 ft  fiberglass pole 
and covers 40, 30, and 20 using loading coils on the lower bands.  I 
couple it to the 50 ohm feed line using a link coupled tuned tank 
circuit to accommodate the very high feed point impedance.  Since that 
impedance can be in the k-ohms, and the voltages involved increase as 
the square of the power, this setup is strictly a QRP deal.  If I try to 
use more than about 20 w the toroid in the coupler begins to arc like a 
Tesla coil.

The other thing I have encountered with verticals vs horizontal antennas 
in an urban environment is that verticals are inherently noisier.  For 
weak signal situations (QRP Fox Hunts) I've compared the above vertical 
with my inverted V and found that the V wins out on receive SNR most of 
the time.  I've noticed the same thing comparing vertical vs horizontal 
feed setups on a 20 m delta loop I had up for a while.

73,
Brian, K0DTJ


On 6/26/2014 7:59 AM, Doug Person via Elecraft wrote:
> Certainly has me thinking about vertical dipoles.  The half-wave 
> end-fed looks like the perfect candidate for a simple vertical dipole.