Topband: Take-off angle

[k6se@juno.com]

Ford, N0FP wrote:

"I've only got 8 - 50' radials stitched into the sod.  Why only 8?  I'm
lazy!  This summer I intend to correct  that to lower the radiation
angle."
----------
Adding radials does not lower the radiation angle -- it merely increases
the efficiency of the vertical.  Only an increase in the far-field soil
conductivity will lower the angle of radiation.
==========

"Several recent comments have been made about take-off angle and DX.  Is
there such a thing as "too low" a take off angle?"
----------
The lowest angle of radiation antenna I have ever used is the
balloon-supported 1/4-wave vertical at Koehn Dry Lake bed, where the soil
conductivity is better than sea water.  Computer modeling shows that max
radiation is less than 7 degrees above the horizon.  Judging by my
160-meter contest results there and from e-mail comments about my signal,
an antenna with that low of a radiation angle appears to be an asset
rather than a problem.

Because of the very high soil conductivity there, I was able to get away
with using only four 125-foot radials lying on the ground.  The measured
feedpoint impedance at resonance was about 38 + j0 ohms, which means the
ground loss was only about 2 ohms with only 4 radials.
==========

"....does it make sense to set a ring around the base of the tower, hook
the bulk of the radials to the ring, and switch it into the system for DX
work?  My gut tells me that I will never hear any difference."
----------
As I mentioned, the number of radials has nothing to do with angle of
radiation.  It also has mothing to do with the S/N ratio of the antenna
on receive, so your gut feeling is correct.

Go ahead and and hook all of your radials to the ring, but don't go to
the trouble of rigging something up to switch your radials in and out of
the circuit.

73, de Earl, K6SE