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#11
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Cecil Moore wrote:
John Smith wrote: Perhaps a very high resistance hooked to the radiator and gnd would be the quick, cheap fix? Perhaps not. Such is already provided inside the SG-230. Cecil: I am slow to fence with you, your logic is impressive; however, perhaps this "safe guard" has failed? It is hard for me to picture static which is able to resist (pun intended) a path to ground ... Regards, JS |
#12
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Cecil Moore wrote:
John Smith wrote: How many power lines do you see running vertically? How many ground wires do you see running vertically from power pole capacitors and transformers? :-) Cecil: True. But, given the hundred-of-thousands/millions? of miles in conductors, carrying noise generating power in a horizontal plane, those ground wires must only amount to a small percentage of the whole ... Regards, JS |
#13
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Cecil if a static charge has a time varying field applied by gravity
would it have radiatiatonal properties and if so would it not be vertically polarised? Can't be true as it is not printed in a book ! Cecil Moore wrote: John Smith wrote: Perhaps a very high resistance hooked to the radiator and gnd would be the quick, cheap fix? Perhaps not. Such is already provided inside the SG-230. -- 73, Cecil http://www.w5dxp.com |
#14
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John Smith wrote:
I am slow to fence with you, ... On guard, varlet! :-) your logic is impressive; however, perhaps this "safe guard" has failed? It is hard for me to picture static which is able to resist (pun intended) a path to ground ... If the SG-230 weren't there you would be right. But the SG-230 already has two built-in paths to ground from the main RF line. One is about 40K ohms resistive and the other is 20 turns on a transformer, probably a toroid. Your high-resistance path would probably have negligible effect in this particular situation. Tom, W8JI, explained it as not just a static charge problem but as an RF problem. If the impedance is low enough to discharge RF static, then it is also low enough to discharge desirable RF signals. What a parallel impedance does is prevent arcing due to static DC buildup but it does little to prevent RF noise due to precipitation static which is many small discharges but only one small one at a time. (Someone reported being able to count the charged snowflakes.) In the absence of a parallel impedance as exists in the SG-230, a parallel impedance can certainly eliminate DC arcing along with its associated corona so it's not a bad idea. But precipitation static is a number of small hits each generating a small amount of RF energy. The only way I know of to reduce the amount of that RF energy reaching the receiver is to partially short it out with a loop antenna or insulate the antenna from the physical hits. And in fact, those are the most popular ways of reducing precipitation static on airplane antennas. -- 73, Cecil http://www.w5dxp.com |
#15
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John Smith wrote:
Cecil Moore wrote: How many ground wires do you see running vertically from power pole capacitors and transformers? :-) True. But, given the hundred-of-thousands/millions? of miles in conductors, carrying noise generating power in a horizontal plane, those ground wires must only amount to a small percentage of the whole ... A small percentage of the length of wires - a very large percentage of the vertically polarized noise. Probably two S-units of noise at my QTH that goes away during a power failure. -- 73, Cecil http://www.w5dxp.com |
#16
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![]() "Cecil Moore" wrote in message ... bad idea. But precipitation static is a number of small hits each generating a small amount of RF energy. The ... a loop antenna or insulate the antenna from the physical hits. And in fact, those are the most popular ways of ... 73, Cecil http://www.w5dxp.com Cecil: Stated was: "Interesting Cecil, my vertical antenna is constucted from a 42 foot length of coaxial cable using the outer braid as the radiator (but the inner and outer are shorted together anyway) and this fat vertical "wire" is suspended inside a telescopic fibre glass pole from Spiderbeam ( not the conductive type). So, I guess my verical wire is quite well insulated and certainly not in contact with charged rain." How better could the actual metal radiator (receiving element) be insulated from the physical striking of rain drops, other than in the nonconductive fiberglass casing it already resides in? What am I missing? Warmest regards, JS |
#17
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art wrote:
Cecil if a static charge has a time varying field applied by gravity would it have radiatiatonal properties and if so would it not be vertically polarised? Can't be true as it is not printed in a book ! Whoa there, Art. There seems to be confusion between two topics. As far as I know, there is no obvious difference between the precipitation static levels on a horizontal Vs vertical antenna. That this particular antenna is vertical is mostly irrelevant to the alleged precipitation static problem. It could just as easily be happening with a horizontal antenna. The fact that the noise might be attributed to something other than precipitation static might involve vertical polarization but I don't think precipitation static has much to do with polarization. A wind-driven charged particle is just as likely to encounter a vertical wire as a horizontal wire. -- 73, Cecil http://www.w5dxp.com |
#18
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Cecil:
Undoubtably, in a power failure, "most all" of the noise, both horiz and vert, goes away. How to you differentiate between what is the horiz component and that of the vert component? Regards, JS "Cecil Moore" wrote in message . .. John Smith wrote: Cecil Moore wrote: How many ground wires do you see running vertically from power pole capacitors and transformers? :-) True. But, given the hundred-of-thousands/millions? of miles in conductors, carrying noise generating power in a horizontal plane, those ground wires must only amount to a small percentage of the whole ... A small percentage of the length of wires - a very large percentage of the vertically polarized noise. Probably two S-units of noise at my QTH that goes away during a power failure. -- 73, Cecil http://www.w5dxp.com |
#19
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On Sat, 09 Dec 2006 07:27:39 -0800, John Smith
wrote: Dave wrote: ... Most all verticals have higher noise levels than horizontal antennas. Reason, as it is reported, is that man made noise is vertically polarized. Dave: Frankly, I think that the statement, "most man made noise is vertical polarized" is a myth. How many power lines do you see running Perhaps the explanation for the observation that the vertically polarised component of man made noise is greater at a receiver antenna than the horizontal component lies in the propagation mechanism. Most man made noise is received from nearby and by ground wave, and vertically polarised ground waves are attenuated less than horizontally polarised waves over the same path. This explanation is supported by the observation that the closer one is to a high intensity man made noise source (but still within radiating far field), the less variation in field strength with antenna polarisation. Owen -- |
#20
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John Smith wrote:
How better could the actual metal radiator (receiving element) be insulated from the physical striking of rain drops, other than in the nonconductive fiberglass casing it already resides in? What am I missing? Netnews is a challenge. Apparently you have read his followup posting without reading mine. Just be patient. My followups will arrive on your server sooner or later. For instance, if he has uninsulated elevated radials, the same thing might be happening. Or maybe it's noise from lightning and not precipitation static at all. -- 73, Cecil http://www.w5dxp.com |
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