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#11
September 6th 09, 07:16 PM
posted to rec.radio.amateur.antenna
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Corriolis force
On Sep 5, 7:29*pm, Art Unwin wrote:
On Sep 5, 6:02*pm, JIMMIE wrote: On Sep 5, 6:37*pm, "christofire" wrote: "Art Unwin" wrote in message .... On Sep 5, 3:17 pm, "christofire" wrote: "Szczepan Białek" wrote in message -- snip -- If you want to discover what radiates I suggest you read one of the normal text books on the subject, like Kraus 'Antennas', and stop making up your own versions! To discower what radiates will be better to do experiments with tipping of monopole antenas. * Where do you get this stuff from? Please visit a library - you could do yourself a lot of good. Chris Chris, what I believe he is referring to is that computer programs support a tipped vertical over one at right angles to earth. Computer programs are supposed to be based on Maxwell's formula. Is this an error and how do we fix it. If it is not an error then it supports the presence of the Coriolis force in collusion with gravity. and not gravity alone. * I don't doubt that it is possible to obtain results from a computer program that appear to contradict conventional theory. *Interpretation of what comes out is always the responsibility of the operator so, whilst anyone can enter parameter values and hit 'go', not everyone will interpret the results correctly. *In this respect it must help greatly to have a clear understanding of the basic principles of how antennas radiate and how the modelling programs operate; in most cases how the moment method works.. *My recommendation, as before, is to read an edition of 'Antennas' by Kraus (or an equivalent), cover to cover, before trying to make sense of the output of any antenna modelling program. *Of course, I realise that some who 'publish' here feel this would be beneath them, or too hard ... but, really, it is neither. My own take on the effect of tilting a vertical antenna is that if its length is an appreciable fraction of a wavelength then tilting it will distort its radiation pattern and will upset the uniformity of its polarisation, which will impose a further effective radiation pattern.. *If this results in a bit of gain in one particular direction with respect to a particular polarisation then fine, and this may be of some use in amateur radio service although it isn't how vertical monopoles are most often used (i.e. their omni-directional pattern is their strength and there are many other, better ways, to obtain directional patterns). However, the theory on which all the well-known modelling programs is based is the simple stuff described by Kraus, et al, and probably in most cases follows from the original work that led to NEC (http://www.nec2.org/other/nec2prt1.pdf). *It takes _no_ account of the Coriolis force or gravity (outside of its impact on the speed of light). *If such a program produces output that the operator interprets as depending on the Coriolis force then, logically, this must be a mistake on the part of the operator - wouldn't you agree? *However, if you believe the theory on which the program is based is in error then maybe you shouldn't use it. |
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