This is a repeat of two of my previous posts on wire antennas. de N4KG
..................
The G5RV is a 100 foot center fed wire antenna.
Think of it as a long wire for each band and look up the patterns
for each length in the ARRL Antenna Book or other source.
80M .35 WL "short" dipole figure 8 pattern broadside to wire
40M .70 WL "long" dipole figure 8 pattern broadside to wire
30M 2X .5 WL Two Half waves in phase - figure 8 pattern
50 degrees wide broadside to wire
20M 3/2 WL current fed LW - 6 lobes - 4main lobes approx 35* to wire
2 minor lobes broadside to wire
17M 2X 1 WL voltage fed LW's - 4 lobes approx 40* to wire
15M 2X 1.1 WL voltage fed LW's - 4 major lobes, possible minor
(this is my "intuitive analysis...check w/modeling
program)
12M 5/2 WL current fed LW - 10 lobes - 4 main lobes approx 30* from
wire
10M 2X 3/2 WL voltage fed LW - 6 lobes - 4 main lobes approx 35* to
wire
2 minor lobes broadside to wire
de Tom N4KG
............................
WARC Antennas de N4KG
One of my favorite subjects!
First off, a LEVEL (or nearly level) 80M dipole makes a great LW antenna
for all three WARC bands, in the diredtion of the main lobes
(approximately
30 degrees either side of the wire, at both ends) plus some narrow lobes
in between. An 80M CW dipole is roughtly 3/2 wavelengths on 30m,
exactly 5/2 WL on 17M, and exactly 7/2 WL on 12M, presenting
approximately
100 ohms at the feedpoint. My 75 ohm fed 80M dipole presents a 3:1 SWR
on 30M (use a tuner if you are squemish or have a solid state exciter),
and
under 2:1 on 17 and 12M.
My FAVORITE WARC antenna is a 20M dipole fed with ladder line. It has
a figure 8 pattern from 10 through 30 meters, varying from 50 degrees
wide
on Ten to 90 degrees wide on 30M.
Using only a pair of 80M dipoles and high band dipoles, I have managed to
work over 290 countries on 12 and 30, and over 300+ on 17M. It has been
a fun learning experience in both propagation and antennas!
If you prefer aluminum antennas,
the Cushcraft D3W is a nice 3 band dipole for 12/17/30M. There are
several
good 3 element Yagis for 12 and 17M from Cushcraft, HyGain, and Mosley.
Force 12 and HyGain make some nice longer boom monobanders.
BTW, your 402CD will work well as a rotary dipole on 17M with under
a 2:1 SWR. It can even be used on 12M but the SWR is higher. Place
a 12 and 17 M reflector behind the driven element, and you have a 2L
Yagi for those two bands!
73 / GL de Tom N4KG
............................
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