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Cecil Moore wrote in message ...
Art Unwin KB9MZ wrote: No I have not, but I have made one using hardline coax for use on the antenna when the weather gets better. we have ice up here !. What is the basis of your suspicioun regarding 'Q' ? The flux from each loop flows across all the other loops. A web search for "pancake coil" turns up some interesting stuff including one company's claim that their coil-on-chip process turns out coils with double the 'Q' of pancake coils. Cecil I suspect that the 'Q' of a pancake coil would be higher than the single layer solenoid coil. !. Modeling shows that for a given length the inductance supplied is about equal with the edge going to the pancake coil. 2 I believe it is well established that the'Q' of the standard coil increases as the former radius increases. Based on the above one could roughly equate the relative inductances as somewhat proportional with the mean diameter of coils. 3 Since the first pancake coil would have a diaameter more than zero I think one could say that the pancake coil would tend to have a higher "Q' and not the lower "Q" that you suspect. If a whip coil was made pancake style would this not present less wind resistance when going mobile ? Cheers Art Incidentally, a pancake coil doesn't solve the magnitude difference problem between current in and current out in a standing wave antenna. It may not radiate but it certainly has a delay through the coil which is what causes the current in to be different from the current out in standing wave antennas. This is explained on my web page at the bottom of the page. -- 73, Cecil, http://www.qsl.net/w5dxp/current.htm |
#2
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![]() "Art Unwin KB9MZ" wrote in message m... Cecil Moore wrote in message ... Art Unwin KB9MZ wrote: No I have not, but I have made one using hardline coax for use on the antenna when the weather gets better. we have ice up here !. What is the basis of your suspicioun regarding 'Q' ? The flux from each loop flows across all the other loops. A web search for "pancake coil" turns up some interesting stuff including one company's claim that their coil-on-chip process turns out coils with double the 'Q' of pancake coils. Cecil I suspect that the 'Q' of a pancake coil would be higher than the single layer solenoid coil. !. Modeling shows that for a given length the inductance supplied is about equal with the edge going to the pancake coil. 2 I believe it is well established that the'Q' of the standard coil increases as the former radius increases. Based on the above one could roughly equate the relative inductances as somewhat proportional with the mean diameter of coils. 3 Since the first pancake coil would have a diaameter more than zero I think one could say that the pancake coil would tend to have a higher "Q' and not the lower "Q" that you suspect. Cecil, Correction needed here! The mean diameter of a pancake coil depends mainly on the radius of the first coil form thus the "Q" can easily made of either a higher "Q" or a lower "Q" over a standard solenoid style coil.depending on the relative diameters' Cheers Art If a whip coil was made pancake style would this not present less wind resistance when going mobile ? Cheers Art Incidentally, a pancake coil doesn't solve the magnitude difference problem between current in and current out in a standing wave antenna. It may not radiate but it certainly has a delay through the coil which is what causes the current in to be different from the current out in standing wave antennas. This is explained on my web page at the bottom of the page. -- 73, Cecil, http://www.qsl.net/w5dxp/current.htm |
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