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#1
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I am trying to build a 20meter 1/2wl end fed vertcal antena and havent had a
lot of success. The antenna is for use at maximum legal power so I need componets in the network that will hold up. I have tried a J pole configuration that I never was able to properly tune and I have tried lump sum LC values that melted down with max power. I guess the last way is doable but not unless I want to spend really big bucks on new HV capacitors. I was thinking about the matching section on my Ringo Ranger. Why not just scale this up for 20M? The mechanics of it arent a real problem, I can fabricate most anything I would need. Seems like I've heard the mast for a Ringo needs to be at least a 1/4 wl long, is this true? |
#2
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Feed it through a 1/4 wavelength stub.
Jimmie D wrote: I am trying to build a 20meter 1/2wl end fed vertcal antena and havent had a lot of success. The antenna is for use at maximum legal power so I need componets in the network that will hold up. I have tried a J pole configuration that I never was able to properly tune and I have tried lump sum LC values that melted down with max power. I guess the last way is doable but not unless I want to spend really big bucks on new HV capacitors. I was thinking about the matching section on my Ringo Ranger. Why not just scale this up for 20M? The mechanics of it arent a real problem, I can fabricate most anything I would need. Seems like I've heard the mast for a Ringo needs to be at least a 1/4 wl long, is this true? |
#3
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Jimmie D wrote:
I have tried a J pole configuration that I never was able to properly tune ... Why did you give up before it was properly tuned? -- 73, Cecil http://www.qsl.net/w5dxp |
#4
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On Mon, 4 Sep 2006 00:45:07 -0400, "Jimmie D"
wrote: I am trying to build a 20meter 1/2wl end fed vertcal antena and havent had a lot of success. The antenna is for use at maximum legal power so I need componets in the network that will hold up. I have tried a J pole configuration that I never was able to properly tune and I have tried lump sum LC values that melted down with max power. I guess the last way is doable but not unless I want to spend really big bucks on new HV capacitors. I was thinking about the matching section on my Ringo Ranger. Why not just scale this up for 20M? The mechanics of it arent a real problem, I can fabricate most anything I would need. Seems like I've heard the mast for a Ringo needs to be at least a 1/4 wl long, is this true? You might want to consider this approach. http://k6mhe.com/files/DualBandVert.pdf Danny, K6MHE |
#5
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That is EXACTLY what I tried less the relays. Problem is I dont have good
enough caps for full power and probably will not get any. I am trying to make do with what I have. It worked fine with 100 watts. I am considering lengthening the antenna to 5/8 wl. This should give me a lot less voltage at the feedpoint and I shouldnt even need a capacitor. I did like the idea of dual band antenna . "Danny Richardson" wrote in message ... On Mon, 4 Sep 2006 00:45:07 -0400, "Jimmie D" wrote: I am trying to build a 20meter 1/2wl end fed vertcal antena and havent had a lot of success. The antenna is for use at maximum legal power so I need componets in the network that will hold up. I have tried a J pole configuration that I never was able to properly tune and I have tried lump sum LC values that melted down with max power. I guess the last way is doable but not unless I want to spend really big bucks on new HV capacitors. I was thinking about the matching section on my Ringo Ranger. Why not just scale this up for 20M? The mechanics of it arent a real problem, I can fabricate most anything I would need. Seems like I've heard the mast for a Ringo needs to be at least a 1/4 wl long, is this true? You might want to consider this approach. http://k6mhe.com/files/DualBandVert.pdf Danny, K6MHE |
#6
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![]() "Cecil Moore" wrote in message m... Jimmie D wrote: I have tried a J pole configuration that I never was able to properly tune ... Why did you give up before it was properly tuned? -- 73, Cecil http://www.qsl.net/w5dxp Sold my antenna support, 3 story house. |
#7
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![]() "Dave" wrote in message . .. Feed it through a 1/4 wavelength stub. That was my first thought and I invisioned 16 ft of open wire line runing out across the yard. But now that I think of it this may be a workable solution. No reason it has to be stretched out straight, circle it around the antenna. Hmm back to Ringo again. Jimmie D wrote: I am trying to build a 20meter 1/2wl end fed vertcal antena and havent had a lot of success. The antenna is for use at maximum legal power so I need componets in the network that will hold up. I have tried a J pole configuration that I never was able to properly tune and I have tried lump sum LC values that melted down with max power. I guess the last way is doable but not unless I want to spend really big bucks on new HV capacitors. I was thinking about the matching section on my Ringo Ranger. Why not just scale this up for 20M? The mechanics of it arent a real problem, I can fabricate most anything I would need. Seems like I've heard the mast for a Ringo needs to be at least a 1/4 wl long, is this true? |
#8
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Jimmie D wrote:
"Cecil Moore" wrote in message Why did you give up before it was properly tuned? Sold my antenna support, 3 story house. The matching section for your 20m 1/2WL monopole can be mounted horizontal if it is more convenient. FP is where it connects to the 1/2WL vertical section. +-----------X-----------16.5'---------------+FP | +-----------Y-----------16.5'----------------open The coax connects at X and Y where the 50 ohm feedpoint is located. #14 or larger wire will handle anything legal that you can put into it. No high voltage capacitors required. No lossy coils required. -- 73, Cecil http://www.w5dxp.com |
#9
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![]() Jimmie D wrote: "Dave" wrote in message . .. Feed it through a 1/4 wavelength stub. That was my first thought and I invisioned 16 ft of open wire line runing out across the yard. But now that I think of it this may be a workable solution. No reason it has to be stretched out straight, circle it around the antenna. Hmm back to Ringo again. Have you tried using coax for the caps, same as the cushcraft ringos? I'm not sure how much power a cap made from say 213 would handle, but it going to be several hundred watts at the min.. I've built what you are building. It will work fine, and the height above ground is not that critical. But I eventually changed the antenna to be a 40 GP and a 5/8 GP for 17m. I used a relay to switch the loading coil for 17m in/out. The "gamma loop" for 20m is kinda large, so you need some stiff tubing to hold stable. IE: copper tube, etc.. MK |
#10
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![]() "Cecil Moore" wrote in message m... Jimmie D wrote: "Cecil Moore" wrote in message Why did you give up before it was properly tuned? Sold my antenna support, 3 story house. The matching section for your 20m 1/2WL monopole can be mounted horizontal if it is more convenient. FP is where it connects to the 1/2WL vertical section. +-----------X-----------16.5'---------------+FP | +-----------Y-----------16.5'----------------open The coax connects at X and Y where the 50 ohm feedpoint is located. #14 or larger wire will handle anything legal that you can put into it. No high voltage capacitors required. No lossy coils required. Thanks Cecil This was my first plan but I dont have room to run the stub straight out so I kind of tabled the idea for a while. Now that I have thought about it there is no reason I couldnt wrap it around the antenna. Talking with others sure helps the thought process. I still may play with the idea of the 20M Ringo design. It would be a lot of fun telling people you have a 20M Ringo Ranger. My only real problem with using the Ringo style matching network is that I heard once upon a time that the Ringo utilizes the mast as part of the radiator. The main thing I see the Ringo type match has going for it is that it would be about half the size of a 16.5 ft stub wrapped around the antenna |
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