The elevation patterns of vertical monopoles over real earth has been discussed in recent threads here (http://lists.contesting.com/archives//html/Topband/2012-10/msg00140.html). The common belief ba
I have long had a suspicion that some fraction of the power in surface wave must be "converted" to skywave as the surface wave encounters discontinuities in the ground medium (both physical geometry
The tangle of tree roots in woods or forest is a discontinuity. It's an immediate discontinuity if the antenna IS in woods or forest (like mine). A vein of sandy soil that angles into the ground goin
Guy Olinger wrote: But to prove it we can't use standing-man-with-meter. He may just be sensing the current in the ground just below his feet that will never be airborne. We need sitting-man-with-met
We need sitting-man-with-meter-in-helicopter to go up there and prove that what you get from the ground up to twenty thousand feet out (at) 20 miles is a blend, and not a notch. Below is a link to th
Hi Dick, I get that at any point in the far field there is RF current in the ground due to the space wave from the transmitter reflecting obliquely off ground. I was, however, under the impression th
I get that at any point in the far field there is RF current in the ground due to the space wave from the transmitter reflecting obliquely off ground. If the earth had perfect conductivity then an EM
Guy Olinger wrote: I find it curious that some of those that so insist on standing-man-with-meter in affairs regarding performance of antennas are willing to accept a considerable logical reach on "u
The measured MW data looks compelling and agrees with the NEC surface wave analysis. Even accounting for frequency disparity between the BC band and 160m, low angle field strength remains robust. Ric
See Richard's quoted table below. Various combinations of the answers to questions below could invalidate the conclusions Richard draws from those figures, or concretely establish them. ** What was t
** What was the station and location? This allows us to view the location ourselves with Goggle Earth and other tools. etc etc etc The data I posted was sent to me as a courtesy by the consulting eng
The measured fields by the consultant show that no "notch" exists in the elevation pattern of that monopole from 0-3 degrees. Nor would one appear in the elevation pattern of ANY monopole up to 5/8-w
This may be the nub of it, and it comes apart with our two fairly separate uses. Hams are after sky wave, and local area or even regional groundwave could matter less to most. For those trying to com
Mr. Fry supplies a monolithic, complete fill up to three degrees at some unspecified frequency over unspecified ground out 2.8 km. The difference between that and the NEC pattern generated for 1/4 wa
Yes. But again, does that mean ANY vertical radiator automatically gets the low angle radiation no matter what? Does this persist for me working Russians on 160, or is it lost. Is the notch correct i
As W8JI pointed out, this is nothing new. Academics like Terman, BL&E, et. al. were teaching it back in the early 1930s. But we've become firm believers in the typical vertical profile field plots wh
But that is NOT the radiation pattern existing close to the monopole, regardless of earth conductivity. That pattern has substantial radiation at angles below 15 degrees. Such radiation will be show
It will be seen from the data that no "notch" exists in the fields radiated by the monopole at elevation angles of 3 degrees and less, as expected by some when considering only the far-field patterns
So again my question - if this low-angle ground-wave (aka surface-wave) energy dies off so quickly (e.g. down 20dB at just 20 miles), how does any of it get to the ionosphere where it can be useful f
The field over real earth that exists within a few kilometers of a monopole is not very much less for an elevation angle of 10 degrees than it is for the peak radiated field from that monopole. This