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Art Unwin wrote:
On Mar 10, 8:07 pm, tom wrote: Art Unwin wrote: A Faraday shield allows for magnetic and elerctrical fields to separate and cancell leaving a RF current thast radios are designed to handle No, that's absolutely incorrect. Nothing is separated. And what's left over, if anything measurable is, is an electromagnetic wave. The shield unlike what we view as radiators has two side that are independent of each other where as a "normal" radiators surface is not separated electrically. The Faraday shield operates at 90 degrees to an oncomming signal by a blocking method and does not operate as a recieving type surface that is directly connected to a radio. No it doesn't. You are wrong. The Faraday shield as a single wall still has a blocking action as fields can encircle the wall but it cannot protect all. It does however protect the rear surface from field impingement and the field usually will connefct to a alternate surface leaving a void directly behind the shielding wall. The Faraday shield on the other hand is an enclosure that shields the inside from encroachment on the outside such thast fields do not interfere with activities within. It does not perform the function of field separation. In most radio circuits you will see examples of bot enclosures and shields where the latter incorporates physically unconnected surfaces for electricaly closed loops. I don't mind your postings Tom as it provides those that are educated some idea of your true standing in life. With respect to a closely aligned feed which to your mind leaves an imediate short;. I suggest you look at a three band dipole all connected at the same point. Each dipole provides a low resistance path for a particular applied frequency in its seach for a closed circuit. The applied current will not divert to a path of higher resistance or impedance in this case because we have to consider the effect of phase differences. With these sort of actions we can have several different paths for the current to follow but I assure you that it will pick the same one every time dependent on the frequency applied. Now to the wire mesh curtain. It provides a separate low impedence path for every frequency applied to it as well as a separate path for the displacement current that encloses a separate field ( see my page) which has the abilitity to accellerate mass as with an electric gun.The maximum accelleration applied to mass is obviously determined by its intrinsic mass where a minimum mass determines the speed of light. Today the smallest particle found is that of a Neutrino thus one can see the connection of the Sun to communication as we see it today. Regarding your description of the shield to a long wire or dipole, gthe curtain or shield does not provide a electrical connection for both sides of the shield as a dipole or long wire does. See Tom, your past postings are completely devoid of technical content and probably provide all readers with a silent chucklel By the way, a curtain is able to supply a very large aperture which is synonimous with the amount of gain it supplies. You might want to ponder on that aspect before you disparage it. The above is provided for you and your friends to salivate apon so you may provide a few more chuckles to those on the side lines. Note I have left some grammerr and spelling errors for you to comment upon in the absence of any technical content. Cheers and beers Art Unwin KB9MZ.....xg And I'll just summarize all the last part, since it would be a total waste of time to comment individually on points - YOU ARE WRONG. Totally, completely, and terribly wrong. And no, I'm not going into how or why, because you never ever listen or understand. tom K0TAR Oh My. I am wrong but you are unable to describe how I am wrong,how convenient! If you were to supply a sufficient description of what you have done, you might to get more detailed responses. For example, it is unclear how you have connected the feed line to the mesh. A photo (you have a website, you could post it there) would make the details much clearer. You have not specified the nature of the mesh (the material, the thickness of the wire (assuming it is wire), how the intersections are joined, etc.). The orientation of the mesh relative to the ground is not specified. You seem to expect detailed responses without out providing any details on your part. You need to brush up on attenuation versus skin depth, surface conduction and a host of other things such as a sealed surface can be considered as an aperture with respect to shielding. I would recommend a book on shielding etc by Ralph Morrison 5 th edition that will bring you up to date on the function of perforated shielding plates, screening etc. Just saying that I am wrong without explanation or explaining your record on the subject is nothing more than the voice of a child exercising free speech. Just believing you are right without providing any details does not mean we have to accept what you say. If you can provide technical data to support your position we can discuss but just saying one is wrong serves nobody. Where are the technical details to support what you are syaing about this antenna? Frequency of operation: unspecified. Performace relative to known/understood reference antennas: unspecified. Feedpoint impedance: unspecified. Test conditions/setup: unspecified. One thing you really need to understand is the nature of a accellerated and decellerated charge and its connection with a time varient current, the latter being the only connection that a xmitter or rcvr can handle to provide communication and its connection with a parallel tank circuit. You have failed to show how a parallel tank circuit applies. Have a happy day Art |
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