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#21
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Joe Bloe wrote:
Gee. . . You're sure a cheery fellow. Hi Rob - Richard has a way with words. Stick with him, and you'll start to enjoy it, once you get used to the prose. I was mostly interested in the Historic Art of the darn thing. I well know it's majorly "Out Dated", but if one does things for the pure enjoyment of it, then I guess it's not the issue of performance, but art, which is also defined by retrieving a wonderful time from out of our past. I'm just a stupid romantic at heat. . . And I enjoy being so. It is a viable antenna, and not outdated. It might help you eke out a bit more bandwidth on 80/75 meters. And as far as I am concerned, it is plenty cool looking too. Okay, so you are a romantic. I have a little bit of that in me too! Try these on for size: Make and use some real open line feeder. This stuff is cool, works really well, and has a real retro look to boot. Most of the time we use plastic spacers these days, but if you want to be authentic, you could use wood dowels soaked in hot paraffin. Of course you'll need a tuner for that setup. How about an "open faced tuner"? Wind the coil on a suitable form, and use clips to attach to it to tune. Make everything pretty, and you'll have a nice nostalgia type station that also works. I'd suggest that the tuner have a plexiglass cover for safety. Old school, You bet. Very very cool though. Thanks for the info though. I guess some how I got the information backwards, but then again, I also see a great many views on the subject of a fat conductor. . . Me thinks the subject still isn't closed due to that simple fact that nobody really yet knows for sure. - 73 de Mike KB3EIA - |
#22
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Richard Clark wrote:
On Fri, 18 Aug 2006 11:43:34 -0400, Michael Coslo wrote: I find the topic interesting, and certainly the feedback I've gotten from Richard and Roy have been very illuminating. So I encourage more on the topic. Hi Mike, Going further, as you encouraged, you can observe the caged concept applied to the Discone antenna at: http://www.qsl.net/kb7qhc/antenna/Discone/discone.htm Fascinating, and thank you! The discone and the Smith charts for it are a great graphic tool. I note that your webpage is also featured in Wikipedia. This also shows how well 16 wires approximate a solid, and further, it also shows how the geometry of the apex angle affects the matching characteristics. This is shown in 7 Smith charts where that angle varies from 20° to 90°. Upon close examination, it appears I report the wrong interval of frequency sweep as every 0.5 MHz. Certainly the range covers 1 to 30 MHz for them all, but it would appear that I shift to every 0.25 MHz for 50° through 90°. - 73 de Mike KB3EIA - |
#23
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This can be done with any EZNEC program type, including the demo:
1. Click Open. 2. Select BYDipole.EZ and click Open in the file selection dialog box. 3. Click SWR. Enter 14 for the start frequency, 15 for the stop frequency, and .05 for the frequency step. Click Run. 4. Using the arrow keys or the mouse, move the cursor in the SWR display to the points where SWR is about 2. These are about 14.1 and 14.75 MHz, indicating a 2:1 SWR bandwidth of about 650 kHz. 5. Click Wires in the main window to open the Wires Window. 6. In the Diameter column, change the Diameter from #12 to 6 to represent a 6 inch diameter cage. (Don't put a "#" in front of the 6.) Press the Enter key to finalize the change. 7. Click SWR. Change the start frequency from 14 to 13 and click Run. 8. In the SWR display, move the cursor as before, and note that the 2:1 SWR bandwidth is now about 1.35 MHz, about twice what it was for the original antenna made from #12 wire. Now you're a Reg-certified expert, even if that took you a month of Sundays to do. You can also get a great deal of additional information from EZNEC, such as the feedpoint impedance and SWR at any frequency, the pattern, and effect of height and ground characteristics. If that took you a month of Sundays, you might think a bit about what's reduced your capabilities to that level. Roy Lewallen, W7EL -- Certified by Reg as both Old Wife and Expert! Reg Edwards wrote: It takes a month of Sundays for an expert to enter and interpret the input/output data of a cage dipole using an Eznec-type program. . . . |
#24
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Dear Roy,
But the subject matter is Cage Dipoles. How many man-hours would it take a novice to enter into Eznec, two, in line with each other, spaced apart, cylindrical cages, 2-feet in diameter consisting of 32, 14-gauge wires, with 4 end rings, with time required to diagnose and eliminate the dozen or more bugs which are sure to be introduced. That is, of course, if the free version will accept such an input. We will forget the 10-day induction course. How long would it take an expert like yourself to enter and fully analyse such a dipole. Bear in mind you would have to enter dipoles consisting of 2, 4, 8, 16, 32 and 64 wires, plus end rings, of say 4 different wire gauges. And obtain the resonant frequencies, input impedances and SWRs of all possible combinations. You will say Eznec is probably more accurate. But DIPCAGE2 will do the same job in a few minutes with an accuracy quite good enough for the intended purpose. CB-ers can use it. With Eznec, before the job was finished I would have forgotten what it was all about, strayed off course and ventured into magloops. To keep you happy, I will repeat what I have said before and say that Eznec does an excellent job in those tasks for which it is primarily intended. What better compliment? I am not in competition with you. ---- Reg, G4FGQ. ======================================= "Roy Lewallen" wrote This can be done with any EZNEC program type, including the demo: 1. Click Open. 2. Select BYDipole.EZ and click Open in the file selection dialog box. 3. Click SWR. Enter 14 for the start frequency, 15 for the stop frequency, and .05 for the frequency step. Click Run. 4. Using the arrow keys or the mouse, move the cursor in the SWR display to the points where SWR is about 2. These are about 14.1 and 14.75 MHz, indicating a 2:1 SWR bandwidth of about 650 kHz. 5. Click Wires in the main window to open the Wires Window. 6. In the Diameter column, change the Diameter from #12 to 6 to represent a 6 inch diameter cage. (Don't put a "#" in front of the 6.) Press the Enter key to finalize the change. 7. Click SWR. Change the start frequency from 14 to 13 and click Run. 8. In the SWR display, move the cursor as before, and note that the 2:1 SWR bandwidth is now about 1.35 MHz, about twice what it was for the original antenna made from #12 wire. Now you're a Reg-certified expert, even if that took you a month of Sundays to do. You can also get a great deal of additional information from EZNEC, such as the feedpoint impedance and SWR at any frequency, the pattern, and effect of height and ground characteristics. If that took you a month of Sundays, you might think a bit about what's reduced your capabilities to that level. Roy Lewallen, W7EL -- Certified by Reg as both Old Wife and Expert! Reg Edwards wrote: It takes a month of Sundays for an expert to enter and interpret the input/output data of a cage dipole using an Eznec-type program. . . . |
#25
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Hi Reg
I sure dont mean to become involved with the discussion on Cage Dipoles, and which method of analyzing them, is better. I do want to give some data concerning the time needed to learn to use EZNEC. It isnt necessary to devote the time of a 10 day course in order to be able to get alot of good/valuable data from EZNEC. At Richard Clark's encouragement, I bought Roy's EZNEC program a couple weeks ago. I was able to get good data from the program that same day, The program is not mysterious. I write this post to make it clear that EZNEC can be learned quickly by anyone who trys, and can be learned in one day. I dont inply that I am a well qualified EZNEC operator, but I have learned so much about the antenna I am investigating that I really treasure this EZNEC program, and recommend it to any HAM who has interest in understanding antennas. Jerry "Reg Edwards" wrote in message ... Dear Roy, But the subject matter is Cage Dipoles. How many man-hours would it take a novice to enter into Eznec, two, in line with each other, spaced apart, cylindrical cages, 2-feet in diameter consisting of 32, 14-gauge wires, with 4 end rings, with time required to diagnose and eliminate the dozen or more bugs which are sure to be introduced. That is, of course, if the free version will accept such an input. We will forget the 10-day induction course. How long would it take an expert like yourself to enter and fully analyse such a dipole. Bear in mind you would have to enter dipoles consisting of 2, 4, 8, 16, 32 and 64 wires, plus end rings, of say 4 different wire gauges. And obtain the resonant frequencies, input impedances and SWRs of all possible combinations. You will say Eznec is probably more accurate. But DIPCAGE2 will do the same job in a few minutes with an accuracy quite good enough for the intended purpose. CB-ers can use it. With Eznec, before the job was finished I would have forgotten what it was all about, strayed off course and ventured into magloops. To keep you happy, I will repeat what I have said before and say that Eznec does an excellent job in those tasks for which it is primarily intended. What better compliment? I am not in competition with you. ---- Reg, G4FGQ. ======================================= "Roy Lewallen" wrote This can be done with any EZNEC program type, including the demo: 1. Click Open. 2. Select BYDipole.EZ and click Open in the file selection dialog box. 3. Click SWR. Enter 14 for the start frequency, 15 for the stop frequency, and .05 for the frequency step. Click Run. 4. Using the arrow keys or the mouse, move the cursor in the SWR display to the points where SWR is about 2. These are about 14.1 and 14.75 MHz, indicating a 2:1 SWR bandwidth of about 650 kHz. 5. Click Wires in the main window to open the Wires Window. 6. In the Diameter column, change the Diameter from #12 to 6 to represent a 6 inch diameter cage. (Don't put a "#" in front of the 6.) Press the Enter key to finalize the change. 7. Click SWR. Change the start frequency from 14 to 13 and click Run. 8. In the SWR display, move the cursor as before, and note that the 2:1 SWR bandwidth is now about 1.35 MHz, about twice what it was for the original antenna made from #12 wire. Now you're a Reg-certified expert, even if that took you a month of Sundays to do. You can also get a great deal of additional information from EZNEC, such as the feedpoint impedance and SWR at any frequency, the pattern, and effect of height and ground characteristics. If that took you a month of Sundays, you might think a bit about what's reduced your capabilities to that level. Roy Lewallen, W7EL -- Certified by Reg as both Old Wife and Expert! Reg Edwards wrote: It takes a month of Sundays for an expert to enter and interpret the input/output data of a cage dipole using an Eznec-type program. . . . |
#26
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On Sat, 19 Aug 2006 04:16:53 GMT, "Jerry Martes"
wrote: Hi Reg I sure dont mean to become involved with the discussion on Cage Dipoles, and which method of analyzing them, is better. I do want to give some data concerning the time needed to learn to use EZNEC. It isnt necessary to devote the time of a 10 day course in order to be able to get alot of good/valuable data from EZNEC. At Richard Clark's encouragement, I bought Roy's EZNEC program a couple weeks ago. I was able to get good data from the program that same day, The program is not mysterious. I write this post to make it clear that EZNEC can be learned quickly by anyone who trys, and can be learned in one day. I dont inply that I am a well qualified EZNEC operator, but I have learned so much about the antenna I am investigating that I really treasure this EZNEC program, and recommend it to any HAM who has interest in understanding antennas. Jerry Jerry, The truth probably lies somewhere between your view and Reg's. Whilst you may have been able to construct a simple model in a very short time, being confident that you have a valid model on even modest antennas takes much more experience and knowledge. I think it is another of those cases where the more I learn, the less I know. You may find the same in time. Owen -- |
#27
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![]() "Owen Duffy" wrote in message ... On Sat, 19 Aug 2006 04:16:53 GMT, "Jerry Martes" wrote: Hi Reg I sure dont mean to become involved with the discussion on Cage Dipoles, and which method of analyzing them, is better. I do want to give some data concerning the time needed to learn to use EZNEC. It isnt necessary to devote the time of a 10 day course in order to be able to get alot of good/valuable data from EZNEC. At Richard Clark's encouragement, I bought Roy's EZNEC program a couple weeks ago. I was able to get good data from the program that same day, The program is not mysterious. I write this post to make it clear that EZNEC can be learned quickly by anyone who trys, and can be learned in one day. I dont inply that I am a well qualified EZNEC operator, but I have learned so much about the antenna I am investigating that I really treasure this EZNEC program, and recommend it to any HAM who has interest in understanding antennas. Jerry Jerry, The truth probably lies somewhere between your view and Reg's. Whilst you may have been able to construct a simple model in a very short time, being confident that you have a valid model on even modest antennas takes much more experience and knowledge. I think it is another of those cases where the more I learn, the less I know. You may find the same in time. Owen Hi Owen I am not qualified to comment on Reg's information on either computer programs or antennas in general. I am not far from being a beginer at antenna design by today's standards. But I was able to get decent data on a 4 dipole array circularly polarized array that requires some phasing of the dipoles. By my standards, that isnt a modest antenna. Richard Clark was god enough to give guidance and encouragement via E-mail. That may account for my being to get such good data on the first day of trying EZNEC. But, he didnt actually provide data. I am not qualified to differ with your observations concerning learning to use EZNEC. But, as must be clear by now, I am really impresed with this program and I consider it learnable with a little time and logic. It is my hope that I can encourage anyone who has interest in antenna design and understanding to 'give it a try'. It doesnt demand a formal training course. EZNEC is a nifty tool. Jerry -- |
#28
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I find Reg's collection and EZNEC both valuable tools.
There are elements of EZNEC that I have not learned to use. In Reg's collection each applet has a tight focus. Yet neither can be considered complete solutions. I am not certain that I am using either correctly without committing the calculations to physical models. de W8CCW John On Sat, 19 Aug 2006 03:15:07 +0100, "Reg Edwards" wrote: Dear Roy, But the subject matter is Cage Dipoles. How many man-hours would it take a novice to enter into Eznec, two, in line with each other, spaced apart, cylindrical cages, 2-feet in diameter consisting of 32, 14-gauge wires, with 4 end rings, with time required to diagnose and eliminate the dozen or more bugs which are sure to be introduced. That is, of course, if the free version will accept such an input. We will forget the 10-day induction course. How long would it take an expert like yourself to enter and fully analyse such a dipole. Bear in mind you would have to enter dipoles consisting of 2, 4, 8, 16, 32 and 64 wires, plus end rings, of say 4 different wire gauges. And obtain the resonant frequencies, input impedances and SWRs of all possible combinations. You will say Eznec is probably more accurate. But DIPCAGE2 will do the same job in a few minutes with an accuracy quite good enough for the intended purpose. CB-ers can use it. With Eznec, before the job was finished I would have forgotten what it was all about, strayed off course and ventured into magloops. To keep you happy, I will repeat what I have said before and say that Eznec does an excellent job in those tasks for which it is primarily intended. What better compliment? I am not in competition with you. ---- Reg, G4FGQ. ======================================= "Roy Lewallen" wrote This can be done with any EZNEC program type, including the demo: 1. Click Open. 2. Select BYDipole.EZ and click Open in the file selection dialog box. 3. Click SWR. Enter 14 for the start frequency, 15 for the stop frequency, and .05 for the frequency step. Click Run. 4. Using the arrow keys or the mouse, move the cursor in the SWR display to the points where SWR is about 2. These are about 14.1 and 14.75 MHz, indicating a 2:1 SWR bandwidth of about 650 kHz. 5. Click Wires in the main window to open the Wires Window. 6. In the Diameter column, change the Diameter from #12 to 6 to represent a 6 inch diameter cage. (Don't put a "#" in front of the 6.) Press the Enter key to finalize the change. 7. Click SWR. Change the start frequency from 14 to 13 and click Run. 8. In the SWR display, move the cursor as before, and note that the 2:1 SWR bandwidth is now about 1.35 MHz, about twice what it was for the original antenna made from #12 wire. Now you're a Reg-certified expert, even if that took you a month of Sundays to do. You can also get a great deal of additional information from EZNEC, such as the feedpoint impedance and SWR at any frequency, the pattern, and effect of height and ground characteristics. If that took you a month of Sundays, you might think a bit about what's reduced your capabilities to that level. Roy Lewallen, W7EL -- Certified by Reg as both Old Wife and Expert! Reg Edwards wrote: It takes a month of Sundays for an expert to enter and interpret the input/output data of a cage dipole using an Eznec-type program. . . . John Ferrell W8CCW |
#29
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![]() "John Ferrell" wrote in message ... Since it appears that the benefit of the cage is bandwidth I ran a few scenario's with EZNEC and a 40 Meter vertical that is 33 feet tall. note that I did not correct for resonance shifting and that I am assuming that whatever the mesh is, it will not beat a solid. http://www.dixienc.us/28FtVert/BandwithVsDia.htm Given that most of us agree that trying to better a 2:1 SWR is into diminishing returns I believe this illustrates the cage's loss of popularity. Defiantly an appealing sight though... de W8CCW John On Wed, 16 Aug 2006 14:06:06 -0700, Joe Bloe wrote: Hello, My attention has been caught by the abilities of a "Fat Conductor" for an antenna. I understand that this has been achieved by using what is (little known about) a Caged Di-Pole. I have seen them before in older photographs, mostly draped over an old steamship, stem to stern. The Caged Di-Pole is supposed to be very well suited for weak signal reception. I know that a Yagi can do very well in this regard, but its the art of it that I'm interested in, and as far as I can see, it's almost an lost aspect of HAM radio nowadays. Does anybody remember these things? 73's Rob John Ferrell W8CCW What if all the wires are not the same length. I know my friends were able to cover all of 75/80 without retuning but this may have been because of the losses in the steel wire they were using.. |
#30
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FINALLY!!! Something good comes from being FAT. When does a FAT antenna become
OBESE?? :-) Jimmie D wrote: "John Ferrell" wrote in message ... Since it appears that the benefit of the cage is bandwidth I ran a few scenario's with EZNEC and a 40 Meter vertical that is 33 feet tall. note that I did not correct for resonance shifting and that I am assuming that whatever the mesh is, it will not beat a solid. http://www.dixienc.us/28FtVert/BandwithVsDia.htm Given that most of us agree that trying to better a 2:1 SWR is into diminishing returns I believe this illustrates the cage's loss of popularity. Defiantly an appealing sight though... de W8CCW John On Wed, 16 Aug 2006 14:06:06 -0700, Joe Bloe wrote: Hello, My attention has been caught by the abilities of a "Fat Conductor" for an antenna. I understand that this has been achieved by using what is (little known about) a Caged Di-Pole. I have seen them before in older photographs, mostly draped over an old steamship, stem to stern. The Caged Di-Pole is supposed to be very well suited for weak signal reception. I know that a Yagi can do very well in this regard, but its the art of it that I'm interested in, and as far as I can see, it's almost an lost aspect of HAM radio nowadays. Does anybody remember these things? 73's Rob John Ferrell W8CCW What if all the wires are not the same length. I know my friends were able to cover all of 75/80 without retuning but this may have been because of the losses in the steel wire they were using.. |
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