Re: Low-angle Elevation Gain of a 1/4-wave Vertical Monopole


On Nov 27, 10:46 pm, Richard Clark wrote:

When I observe the operational characteristics of EZNEC (you report
you use it above) AND I observe that it does not offer a Near Field
analysis for Mininec r-f ground (as you report you use above) THEN I
have to wonder how you arrive at a figure of 72 mV/m (as you report
you obtained above). Other than version differences or updates in the
program that supercede mine, I rely on the advice found in the Help
manual provided:

Near field analysis is disabled when MININEC-type ground is selected.
...Use some other ground type for near field analysis.

Obviously, near-field analysis was not disabled by/in EZNEC for my
model definition. The surface-wave value of 72 mV/m at 1 km for 1 kW
of radiated power is shown in the screen clip I linked to in my first
post about this.

Also consistent is the complete absence of radials in your model - the
hallmark (cogent) research of BL&E's "Ground Systems as a Factor in
Antenna Efficiency."

The r-f loss of the radial system is accounted for in my model by the
two ohms of resistance inserted between the base of the monopole and
ground, as shown in my screen clip. This two ohms is approximately
the r-f loss of a set of 120 buried radials, each 1/4-wave in physical
length.

The peak gain of the elevation pattern in my model (see my screen
clip) is consistent with such a ground loss and the selected ground
conductivity, so this approach appears to be valid.

Hopefully Roy Lewallen will weigh in, as he has time, to comment on
the methods and results of our two analyses -- although probably Roy
will need more details about your model construction than you have so
far been willing to provide.

I will be content to let the chips fall where they may.

RF
.

Relevant Pages

  • Re: Free Will
    ... show that the report is based upon the same implementation details as our ... own consciousness. ... to describe that and the role of internal behaviour in external ... observe indirectly or not at all. ...
    (comp.ai.philosophy)
  • Re: Fridays B.O. has left me feeling sick
    ... and for much the same reason (or maybe people just got ... OBSERVE AND REPORT has a lot more in common with Taxi Driver than it ... does Paul Blart, I had a great time seeing it today.- Hide quoted text - ...
    (rec.arts.movies.current-films)
  • Re: Strange NTP problem on AMD Geode LX cards.
    ... observe that the offset between local time and the external servers is ... Before submitting your report please do the following: ... Upgrade to the current ntp stable _or_ dev release ... Many OSes include statistics logging configuration lines in their sample ...
    (comp.protocols.time.ntp)
  • Re: Current across the antenna loading coil - from scratch
    ... cosIt's a traveling wave current, ... The current reported by EZNEC for StndWave.EZ contains the terms ... cos*cosIt's a standing wave current, ... report traveling wave current. ...
    (rec.radio.amateur.antenna)
  • Re: Security Guard Tells All in New Book
    ... "Observe & Report" does conjure images of point and holler. ...
    (rec.arts.mystery)