[IRCA] longwire turns into EWE into loop

[Charles A Taylor <MWDXer@xxxxxxx>]

At 03:46 AM 8/11/2007 -0700, you wrote:
>Bill,
>
>I am sure there is, but again at what point? I have so many ground rods
>and copper wire buried, I wonder if adding more does any good?

Bill and Patrick,

Perhaps you remember the 65-foot longwire I converted into a EWE antenna
by extending the ends of the longwire 14 feet vertically either end down
the supporting masts. The wire is steel clothesline wire insulated with
vinyl plastic. The masts are three stacked 5-foot sections the type that
RadioShack used to sell. Guys are kevlar rope, and the wire is pulled
tight.

At the far end, I had already driven an 8-foot ground rod, and already
had a 8-foot ground rod at the feedpoint.

I was questioning the true R-F impedance of the far end termination,
and I tried these terminations:

1. No termination, i.e. leaving the far end floating,
2. Grounding the far end directly to the rod with no intervening
    resistance,
3. Terminating with a 200-pF capacitor,
4. Terminating with a 950-µH coil.

I wrote up a paradigm spreadsheet with the frequencies ascending from
530 - 1710 on the far left side, and with four columns with S-meter
readings on each frequency per different termination.

Response in each case varied. In some cases where there are two stations
or more on a frequency, different terminations caused a different
station to predominate on a frequency.

The first conversion from Marconi longwire to EWE caused a startling
change in the characteristics of the antenna.

Thus is true because daytime groundwave signals are vertically polarized,
and a horizontal wire discriminates against them; however, once skywave
appears, it is randomly polarized and the horizontal antenna is
sensitive to horizontally-polarized waves.

The reason a beverage or even a Marconi receives at all is that as
groundwaves travel from the point of origin, they begin to tilt and
become more horizontally polarized.

Where the groundwave contacts the earth, that portion is slowed down by
the earth such that the wave tilts progressively more horizontally.

Back to my EWE antenna.

I buried a "return" wire (again, vinyl-insulated steel clothesline wire),
beneath the horizontal wire. At the far end I terminated the vertical
element directly to the "return" wire. The only ground figuring in this
configuration is an 8-foot rod at the feedpoint. At that point I have
inserted a 9/1 toroid matching and ground-isolation transformer which
feeds the underground feedline back to the house.

The totality is a very "sensitive" coupling device to groundwaves and
high-angle skywaves.

With only one ground connection at the feedpoint, the configuration is
VERY quiet and receives only a minor amount of neighborhood RFI.
Two ground connections at both ends of the "return" wire would cause
random D-C, A-C and RFI currents to flow on the "return" wire and
be impressed on the incoming signals.

UNFORTUNATELY, the whole system is very sensitive to lightning QRN as
it, too, is vertically polarized. Last night was a cacophony of QRN
which made receiving anything but locals impossible!

HOPE Y'ALL FIND THE ABOVE INTERESTING!

Charles








   Charles A Taylor, WD4INP
  Greenville, North Carolina 



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