In article ,
John E. Davis wrote:
The elevation pattern of the antenna shows a hint of the high-angle
secondary lobes which characterize an EDZ.
This is definitely noticable on a log plot.
So, I'd conclude that you've developed a variant on the EDZ (or
something partway between an EDZ and a center-fed fullwave) which
yields slightly lower gain than an EDZ but has a simpler matching
section.
What sort of gain is expected from an EDZ? I tweaked the topology
of my design a bit in the hope of getting a broader bandwidth, but
instead got even more gain. For example, the version represented
below has a minimum gain of more than 4.7 dBi (at the side) and more
than 5.25 dBi in the forward direction. Previously I reported gain
values that ran from 4.2-4.7 dBi. So this one represents a bit of an
improvement.
For an EDZ in isolation (no mast) I believe it's around 3 dBd or 5
dBi, plus or minus a hair.
I modelled a copper-pipe EDZ, mounted at the top end of a conductive
mast. This one came out with 5.85 dBi in the favored direction, and a
2.5 dB front-to-back ratio.
CEDouble extended zepp for 2 meters
GW 1 7 0 0 2 0 0 6.5 1.25 # Upper segment of mast
GW 2 7 0 0 2 0 0 -2 1.25 # Middle segment of mast
GW 3 100 0 0 -2 0 0 -112.5 1.25 # Lower segment of mast
GW 4 15 0 0 2 13 0 2 0.5 # Upper support bar
GW 5 15 0 0 -2 13 0 -2 0.5 # Lower support bar
GW 6 7 13 0 2 13 0 -2 0.5 # Shorting bar
GW 7 7 13 0 2 17 0 2 0.5 # To top of balun
GW 8 7 13 0 -2 17 0 -2 0.5 # To bottom of balun
GW 9 15 17 0 2 28 0 2 0.5 # To top arm
GW 10 15 17 0 -2 28 0 -2 0.5 # To bottom arm
GW 11 40 28 0 2 28 0 46 0.5 # Upper arm
GW 12 40 28 0 -46 28 0 -2 0.5 # Lower arm
GW 13 5 17 0 2 17 0 -2 0.5 # Feedline attachment
GS 0 0 0.0254
GE 0
EX 0 13 3 0 1.0
FR 0 1 0 0 145.27 0.00E+00 0.00E+00 0.00E+00 0.00E+00
0.00E+00
RP 0 61 72 1101 0.0 0.0 3 5
XQ
EN
A stacked pair of them on a single mast yields 8.85 dBi in the favored
direction, with 2.38 dB front-to-back ratio.
--
Dave Platt AE6EO
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