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#1
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Roy, surely you realise that all depends on soil conductivity and
permittivity which B, L & E forgot to determine before leaving the site. 30 years previously, around 1905, Sommerfeld (and others) had produced a significant report showing the importance of ground characteristics on radiation and propagation at LF and below. Which B, L, & E ought to have been aware of if they had known what they were about. You should concentrate your thoughts on HF and above, not on LF and VLF distractions. Different characteristics prevail at HF at which frequencies amateurs are most concerned. ---- Reg |
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#2
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Reg Edwards wrote:
Roy, surely you realise that all depends on soil conductivity and permittivity which B, L & E forgot to determine before leaving the site. It just isn't sinking in, is it? It depends on the conductivity and permittivity to a skin depth or more, which was impossible for them to determine. A surface measurement wouldn't have provided the necessary information. Measurement of ground wave attenuation to another location would have included ground with a variety of possible characteristics different from those in the immediate vicinity. 30 years previously, around 1905, Sommerfeld (and others) had produced a significant report showing the importance of ground characteristics on radiation and propagation at LF and below. Which B, L, & E ought to have been aware of if they had known what they were about. I'm sure they were. But the paper has nothing to do with propagation. What makes you think it does? They certainly did know about the effect of conductivity. In a theoretical analysis at the beginning of their paper they calculated expected radial ground currents for several different ground conductivities, and explain how current is distributed in the ground with conductivity being a factor. The radial ground current analysis was later found to be in error(*), but it's still considerably closer than the results I've seen from your analysis and program. You should concentrate your thoughts on HF and above, not on LF and VLF distractions. Different characteristics prevail at HF at which frequencies amateurs are most concerned. That's a bizarre admonition from someone constantly harping about how many radials American AM broadcasters use. I am indeed most interested in HF, where skin depth is on the order of 12 feet for average soil, and measurement of surface conductivity and permittivity is pretty useless. Incidentally, since you haven't read their paper, you probably don't know that the BL & E measurements were done at 3 MHz, which is HF. (*) To my knowledge, no one has developed a method of calculating radial currents or ground system losses with even approximate accuracy other than with numerical analysis such as used by NEC-4. Many years ago I spent a couple of years of spare time in a technical library looking for just such an analysis without success. Reg's method is delightfully simple but gives results which are very wrong. Roy Lewallen, W7EL |
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#3
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Reggie,
The following is so full of glaring contradictions - well, you can rely on me to point them out. :-) On Sat, 25 Jun 2005 18:34:17 +0000 (UTC), "Reg Edwards" wrote: Roy, surely you realise that all depends on soil conductivity and permittivity which B, L & E forgot to determine before leaving the site. You have thoroughly refuted any intimate knowledge of their paper, it goes unread by you, and yet you "know" this for a fact. Or perhaps that is elevating your prose upon to an unwarranted pedestal. 30 years previously, around 1905, Sommerfeld (and others) had produced a significant report showing the importance of ground characteristics on radiation and propagation at LF and below. Which B, L, & E ought to have been aware of if they had known what they were about. However, your earlier reference to LF from Sommerfeld (and others) is then wholly negated by you with: You should concentrate your thoughts on HF and above, not on LF and VLF distractions. Different characteristics prevail at HF at which frequencies amateurs are most concerned. Back in 1905, they called the frequencies above 1MHz VHF.... So, our trio, B,L, & E could just as easily had dismissed this work as you have? Such legerdemain. Sir Kelvinator asks, "Got any data, Reggie?" This quality of fence sitting - arguing both sides against the middle - is classic Punchinello. 73's Richard Clark, KB7QHC |
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