[Antennas] " G5RV " TYPE ANTENNA / "CUSHCRAFT MA5V"ANTENNA QUESTIONS

[K6MHE]

You're the man!

Thanks es 73

Danny, K6MHE

At 11:26 PM 7/1/2002 -0500, you wrote:
>Danny, I don't know which George you are referring to, but in the event
>that it is this one, let me just say that I think you gave a very good and
>technically accurate picture of the situation.
>
>The basic theory of parallel conductor transmission lines says, of course,
>that as long as the line spacing is "very small compared to a wavelength"
>the EM fields from each conductor will tend to cancel one another and
>thereby minimize radiation.
>
>By the same token, if the conductors are kept several wire-spacings away
>from anything metallic, the net field around the line will be undisturbed
>and the fields' ability to cancel one another will not be impacted.
>
>That is really the problem with having metal too close to the line. The
>presence of the metalaffects one conductor more than the other, that
>unbalances the line in that area,  the fields no longer cancel, and
>radiation can occur. Not to mention the effects on line impedance, etc. of
>the capacitive coupling to the conductors, etc.
>
>The usual rule of thumb is, as Danny reports, to keep the conductors at
>least 2 or 3 line widths away from anything metallic. If you must come near
>something metal, try to do it at right angles to the line for minimum
>coupling effects.
>
>Now, maybe the "real" George can weigh in!   <:}
>
>73/72/oo, George W5YR - the Yellow Rose of Texas
>Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
>Amateur Radio W5YR, in the 56th year and it just keeps getting better!
>QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735
>Icom IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437
>
>
>K6MHE wrote:
> >
> > Criss,
> >
> > The 2=BD to 3 times has been around longer than I. However, if you can
> > picture in you mind the magnetic lines of force surrounding a conductor
> > where current is present and then place two conductors side by side=
 spaced
> > very close with current flow one way in one and the opposite way in the
> > other you should be able to picture in your mind's eye lines of force an
> > choking one another off. (One going is clockwise direction and the other
> > counterclockwise) Nothing expands very far as they've beaten each other
> > down to almost nothing. A little like Dr. Doolittle's pushme/pullme=
 <grin>.
> >
> > Not very scientific explanation, but how I've pictured it for years.
> >
> > I'll stand by and hope George will jump in with a better (and more=
 correct)
> > answer.