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#1
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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 - |
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#2
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"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! 73 H. NQ5H |
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#3
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On Tue, 21 Sep 2004 17:35:16 GMT, "H. Adam Stevens, NQ5H"
wrote: 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! Hi All, The Wine out of the Pacific Northwest is fast gaining a high reputation. Could be from that same warming trend. I must add that this last summer was one of the muggiest I've lived through here. Humidity in the 80s. It almost competes with D.C.'s June weather when I was back there during Reagan's funeral. 73's Richard Clark, KB7QHC |
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#4
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"Richard Clark" wrote in message ... On Tue, 21 Sep 2004 17:35:16 GMT, "H. Adam Stevens, NQ5H" wrote: 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! Hi All, The Wine out of the Pacific Northwest is fast gaining a high reputation. Could be from that same warming trend. I must add that this last summer was one of the muggiest I've lived through here. Humidity in the 80s. It almost competes with D.C.'s June weather when I was back there during Reagan's funeral. 73's Richard Clark, KB7QHC There's a Wasington State Merlot (I'll remember the name next time I look at a wine list) that I like all too much. Now how are we going to connect this to antennas? I know! Empty wine bottles make great base insulators for verticals! 73 H. |
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#5
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On Tue, 21 Sep 2004 17:54:06 GMT, "H. Adam Stevens, NQ5H"
wrote: There's a Wasington State Merlot (I'll remember the name next time I look at a wine list) that I like all too much. Now how are we going to connect this to antennas? I know! Empty wine bottles make great base insulators for verticals! My longwire could almost reach the Chateau Ste. Michelle winery (but was closer to the Columbia winery and closer yet to the Red Hook ale brewery). 73's Richard Clark, KB7QHC |
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#6
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"Richard Clark" wrote in message ... On Tue, 21 Sep 2004 17:54:06 GMT, "H. Adam Stevens, NQ5H" wrote: There's a Wasington State Merlot (I'll remember the name next time I look at a wine list) that I like all too much. Now how are we going to connect this to antennas? I know! Empty wine bottles make great base insulators for verticals! My longwire could almost reach the Chateau Ste. Michelle winery (but was closer to the Columbia winery and closer yet to the Red Hook ale brewery). 73's Richard Clark, KB7QHC THAT'S IT!!! Chateau Ste. Michelle! Thanks! 73 H. |
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#7
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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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#8
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"Mike Coslo" wrote in message ... 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 - It's real enough; literally decimated the world's coral reefs. But the atmospheric carbon budget is still not well understood. However the weather, being a chaotic system, probably becomes more chaotic as more energy is added. For an excellent discussion of chaos and the weather 1000 years ago see "The Great Maya Droughts" by my old buddy Dick Gill. Glaciers and permafrost are melting. Ice core data suggest the CO2 in the atmosphere shot up with the industrial revolution and is at it's highest in 50,000 years. I dove for NASA in 1970 at Tektite II in the Virgin Islands. I went back to the site at St John in 1997. The coral was much harder to find. Where I remembered reefs was sand and sea grass. I'm going back in January. Over 10 years of diving in Hawaii I have watched the coral population at Tunnels Beach, specifically, diminish dramatically. One of my grad students is from Puerto Rico. He's noticed the coral decline in his 20-odd years. Just a couple of degrees dramatically moves the permafrost boundaries. Any Alaskans here? Canuks? How much are we at fault? Can we change anything? I think the answers are some or a lot, yes and no. OB Ham topic. I operated W3YRQ's (Jerre I am sorry if I got your call wrong, it has been 34 years) KWM2 on 20 meter SSB from the Tektite II habitat. I believe Jerre and I are still the only hams to operate on the ocean floor. 73 H., NQ5H |
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#9
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H. Adam Stevens, NQ5H wrote:
OB Ham topic. I operated W3YRQ's (Jerre I am sorry if I got your call wrong, it has been 34 years) KWM2 on 20 meter SSB from the Tektite II habitat. I believe Jerre and I are still the only hams to operate on the ocean floor. Now THAT is cool! What was your setup? - Mike KB3EIA - |
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#10
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"Mike Coslo" wrote in message
... H. Adam Stevens, NQ5H wrote: OB Ham topic. I operated W3YRQ's (Jerre I am sorry if I got your call wrong, it has been 34 years) KWM2 on 20 meter SSB from the Tektite II habitat. I believe Jerre and I are still the only hams to operate on the ocean floor. Now THAT is cool! What was your setup? - Mike KB3EIA - KWM2, SB220 in the habitat. Hy Gain 14AVQ on a barge on the surface. Worked great! SCUBA down to the shack. What fun. Life's been somewhat boring since Tektite. 73 H. NQ5H |
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