At 02:49 AM 2007-09-15, Neil Carr G0JHC wrote:
>I can get the 1st 460ft of a beverage in a straight line at 10ft height,
>then the remaining 125ft to get it to a preferred length of 585ft would
>have to be at a 45deg angle. My question is, should I cut the beverage at
>460ft (A none standard length) or "turn the 45 deg corner" with the other
>125ft for a 585ft recommended length?
I sent Neil a version of this with 5 pattern plots, so sorry if it is
a little cryptic. I was surprised that the pattern for the beverage
with the angled end section wasn't all that bad. If anyone is
interested, I can send them the original message off list.
~o ~oooo o~o ~o~~
I ran some quick plots with EZNEC over High/Accuracy ("average")
ground with four 100 foot radials at each end (elevated by 0.6 feet
with the radials NOT under horizontal wires); 500 ohm
termination. Forward gain at 20 degree elevation was used for the
With final 125 feet at 45 degrees, with 585 feet or about 1.09 wl
overall (RDF=8.83 dB):
Compare to having all 585 feet straight, about 1.09 wl (RDF=9.72):
460 feet straight only, about 0.86 wl overall (RDF=8.32):
As an alternative, consider 460 feet straight, then 70 feet at 45
degrees, about 0.99 wl overall (RDF=8.56 dB):
Compare to having 530 feet straight, about 0.99 wl (RDF=9.18 dB)
There is some degradation of the pattern when the last 125 feet of
the 585 feet is bent at 45 degrees, losing about 0.9 dB of RDF and
causing a 10 degree pattern skew. The RDF is still about 0.5 dB
better than the 460 foot version. The 530 foot (0.99 wavelength)
bent version has a 6 degree skew, but about 7 dB better F/B than the
460 foot version and a very slightly (0.24 dB) better RDF. Which is
better will depend on the location of your likely QRM/N sources.
I can supply EZNEC models or other pattern plots (elevation, etc.).
73, Terry N6RY
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