[Elecraft] High SWR problem

[David A. Belsley]

--On Sunday, August 17, 2003 11:19 PM +0100 Edward Kenworthy 
<edward@kenworthy.info> wrote:

>
> It's connected to the Balun, obviously it plugs into the back of my ATU
> which is then earthed via braided copper to a copper rod.
>
> It's about, hmm, 3m long something of that order.

I don't know, Edward. I really don't see any need at all for a balun in 
this set up, and I think I would avoid the coax as well.  Just run a wire 
from your antenna (20 meters long), to your tuner (set up for a single wire 
feed), and, of course, coax from the K2 to the input of the tuner. If you 
have problems tuning this set up, try varying the length of the feed wire. 
Only a few feet can make a big difference in the impedance that will be 
seen by the tuner, and can bring it into the range that the tuner can 
handle.


>
> I'm using a 4' copper rod stuck into the ground outside my window as my
> counterpoise.

 This rod may serve for an electrical (dc) ground, but it is not likely to 
provide a good RF ground.  Use a counterpoise for that, i.e., a 1/4 wave 
wire run from the tuner ground to where ever is convenient.  Just be sure 
the end of the cp is well insulated from surrounding objects.  The input of 
the cp will be low impedance, low voltage (which is why it works as an rf 
ground).  The other end, however, will be high RF voltage.  So keep it away 
from kids and pets as well.  Use separate cps for each band of operation. 
You may run them parallel for the better part of their lengths, but 
separate the last few feet of the different lengths from the other wires.

best wishes,

dave belsley, w1euy

----------------------------------
David A. Belsley
Professor of Economics