thanks Jim, I am going to measure the current in each of my 4 elevated
radials and see
where I stand.
Bob
K6UJ
On 2/27/16 4:33 PM, Jim Brown wrote:
You may be fairly close. The wild variable is the soil underneath them
and their heights. N6LF recommends doubling the number of elevated
radials to further equalize the currents. I have elevated radials on
two antennas, and only have four.
73, Jim K9YC
On Sat,2/27/2016 11:43 AM, Robert Harmon wrote:
I use four elevated radials for 80m. What I did was hook up my
analyzer to each pair, 90 degrees from one another, without
connecting anything else tune for resonance (just like a dipole,
which it essentially is) Then connect them all together to the
vertical antenna feedpoint coax connection. This worked very well, do
I have equal currents in each radial with this approach ?
Bob
K6UJ
On 2/27/16 9:32 AM, Dennis W0JX via TowerTalk wrote:
The effect of the earth on the radial generally is to detune it and
make it longer electrically than it is. Perhaps Frank W3LPL can add
something here as to why he recommends 70 feet.
As for elevated radials. many studies have concluded, going back as
far as Les Moxon, that quarter-wave elevated radials are about the
worst possible length you can make them. This particular length
makes it very difficult to obtain equal currents in each radial.
Dick Weber, K5IU, wrote an excellent article on this topic, stating
that ideal lengths are 60 degrees (or about 2/3rds of a quarter
wavelength) loaded by a single small coil, or 120 degrees (about
4/3rds of a quarter wavelength) tuned by a variable capacitor, are
ideal lengths. Of course, a multi-band vertical complicates matters
and would require a loading coil for each band.
73, Dennis W0JX
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