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H. Adam Stevens, NQ5H wrote:
"Mike Coslo" wrote in message ... Reg Edwards wrote: "Bill Turner" wrote The voltage at the ends of a half wave dipole can reach thousands of volts even with relatively low power. Trees have been set on fire with as low as 100 watts. Be careful! ============================== Hi Bill, A half-wave dipole is a resonant tuned circuit. A 40 meter dipole using 14-gauge wire has a Q of about 11. At 100 watts there is 85 volts at the feedpoint. The voltage between the ends of the antenna is 85 times Q which equals 956 volts. Therefore, the voltage between one end of the antenna and ground is only 478 volts. And this falls to a much lower value when the end of the wire is in contact with anything by virtue of the very high antenna impedance of around 1500 ohms. Furthermore, the antenna is immediately detuned when it comes into contact with anything and Tx power falls. From where do you get your "thousands of volts" - the old wive's monthly magazines? There are far more Californian forest fires caused by arsonists than 100 watt transmitters. Fortunately, it doesn't seem to have a bad effect on the quality of the wine. Knowing that you are a wine aficionado, I would mention that there is serious concern about the future quality of the wine. It appears that global warming (which doesn't exist ha ha) has been on average warming the regions of California where the wine grapes are grown. This is causing them to ripen prematurely - at least as far as making the best wine is concerned. Let us hope that a solution is in the works! - mike KB3EIA - But Rush said there's no such thing as global warming. (Tell that to all the dead coral and melted glaciers.) So sorry to hear about the wine. Better drink some moore quick! Ahh, I kind of enjoy Rush, or did until he started to get redundant. But I wouldn't take him as a science adviser! ;^) Seriously, I would be willing to entertain the notion that global warming is not happening. But what I need is a good explanation of of the mechanism keeping it from happening. Certainly the oceans can sink some CO2, but only so much. The effect of CO2 on thermal retention in the atmosphere is not bogus, and there are plenty of other gases that are likely a worse problem, such as methane. Methane is hardly being addressed now. There are possible effects that will mitigate the heat retention, but I want to know what they are, not just that the warming effec isn't real. To say that global warming doesn't exist is not far from saying Ohms law is wrong. I wish proof, not politics. unlike El Rushbo, I don't think that every timee it snows is the disproof of it. We might check with our Canadian friends on how their growing season has been affected. - Mike KB3EIA - |
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