[TowerTalk] Conclusion, G5RV vs. Dipole

[n4kg@juno.com]

Unless I am mistaken, there is a HUGE misunderstanding
of how the G5RV antenna works.

The ONLY way it could act as a Top Loaded Vertical is for
the currents in each side of the balanced transmission line
to be EQUAL and flowing in the SAME direction.  If that were
the case, they could be tied together or replaced by a single
wire and attached to the two sides of the horizontal wires at
the top.  I do NOT believe that is the case.

IF the feed is indeed as a split balanced dipole of various 
electrical lengths, then the ladderline is acting as a balanced
transmission line with EQUAL but OPPOSITE currents in
each side and it does NOT radiate.  

As a balanced dipole, it acts as:

3/8 wave (short ) dipole on 80M
3/4 wave (long) dipole on 40M
2 Half Wave dipoles in phase on 30M (Voltage Node feed)
3 Half Wave Long Wire on 20M (current Node at feed)
(almost) 2 Full wave LW's in phase on 17M  (near voltage node)
9/4 wave LW on 15M (neither current nor voltage node at feed)
5/2 wave LW on 12M (current node at feed)
Two 2WL LW in phase on 10M (voltage node at feed)

BTW, as originally designed, the ladderline was meant as
an impedance transformer that provided a reasonable SWR
on SOME bands (but NOT ALL) without the need for a tuner.

de  Tom  N4KG



On Mon, 16 Oct 2000  David Jordan <wa3gin@erols.com> writes:
> Right on Tom...
> 
> A dipole at 1/8 wave above ground is a great NVIS antenna.  Two 
> dipoles at 1/8 wave above ground spaced .67 wavelength feed with open
wire 
> line
> and feed in phase from a center drop or open wire to a tuner is even
> better.  Most of the radiation goes straight up and it's omni
> directional!
> 
> The G5RV is a top loaded vertical on the lowest freq w/ the twin 
> lead radiating as a vertical does...a real compromise if one is looking

> for short skip high angle radiation.
> 
> Have Fun,
> dave
> WA3GIN
> 

________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
http://dl.www.juno.com/get/tagj.

--
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com