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Post by Night Ranger on Oct 22, 2014 8:06:57 GMT -5
The only problem with making wire antennas for CB is that unless you have a really tall tree (or other tall structure) to hoist the antenna up by, it's hard to mount them vertically and get any usable height. But I may have to try this antenna design as I do have one really tall tree to hoist it up by, and it might just work better than my SWR challenged 3 element beam on 10 meters. The wire J-Pole works very well, but the ladder line matching section is affected by water. Expect the SWR to climb from 1.1 to 1.7 when it is raining. Mine is at 86 feet at the top of the antenna. Where I live we have alot of tropospheric ducting at night, so taking that in to account I have managed ground wave contacts from where I live all the way down to Waycross, Georgia with 200 watts carrier on AM (200+ miles). Under normal conditions it is not unusual for me to talk to people 80 miles away. Still using the J_Pole I have gotten 20 over s9 reports out of California on AM with 200 watts carrier and 15 over S9 reports out of the United Kindgom with 200 watts on sideband when the skip was running in my favor. When talking skip the Lazy H beats it easily, and my six element curtain array leaves it in the dirt. The vertical extended double zepp has a very nice flat radiation pattern compared to the J-Pole. If you have a tree than can support a 46 foot long antenna with a 1/2 wave to clear the ground you can probably beat the J-Pole. Below are the wire J-Pole dimensions for 10 meters. www.shadowstorm.com/cb/pdf/10mjpole.pdfNight Ranger
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Post by cbrown on Oct 22, 2014 9:13:10 GMT -5
Sounds to me like you've just chosen your new CB handle......... Nice!
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Post by cbrown on Oct 22, 2014 9:24:36 GMT -5
3db of loss is a bit high. I'd opt for a different type of cable. RG213 is about half the loss. LMR-400 even less. I agree; I wouldn't use anything less than LMR-400.
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Sandbagger
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Post by Sandbagger on Oct 22, 2014 10:49:33 GMT -5
The wire J-Pole works very well, but the ladder line matching section is affected by water. Expect the SWR to climb from 1.1 to 1.7 when it is raining. Mine is at 86 feet at the top of the antenna. Where I live we have alot of tropospheric ducting at night, so taking that in to account I have managed ground wave contacts from where I live all the way down to Waycross, Georgia with 200 watts carrier on AM (200+ miles). Under normal conditions it is not unusual for me to talk to people 80 miles away. Still using the J_Pole I have gotten 20 over s9 reports out of California on AM with 200 watts carrier and 15 over S9 reports out of the United Kindgom with 200 watts on sideband when the skip was running in my favor. When talking skip the Lazy H beats it easily, and my six element curtain array leaves it in the dirt. The vertical extended double zepp has a very nice flat radiation pattern compared to the J-Pole. If you have a tree than can support a 46 foot long antenna with a 1/2 wave to clear the ground you can probably beat the J-Pole. Below are the wire J-Pole dimensions for 10 meters. www.shadowstorm.com/cb/pdf/10mjpole.pdfNight Ranger Thank you! That's exactly what I was looking for, and at the exact frequency! Now I have to find a hunk of ladder line to carve up......
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Post by Night Ranger on Oct 22, 2014 11:43:39 GMT -5
Thank you! That's exactly what I was looking for, and at the exact frequency! Now I have to find a hunk of ladder line to carve up...... Note on the PDF it shows the shield connected to the same side of the ladder line as the radiating wire. According to the web page below doing that will distort the radiation pattern, but leave the SWR unchanged. The web page below says to connect the center conductor to the side with the long radiating wire attached. See below; www.w8ji.com/end-fed_vertical.htmNight Ranger
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Post by ab5ni on Oct 22, 2014 11:47:32 GMT -5
Sandbagger wrote: Well, since I already have the RG-8X, I guess I'm going to just use it, SB. I'm going to move the HTX-10 to my bedroom (already have a ground rod outside), and then it will only be a short run, so I'll live with the loss that remains. Don't forget: I'll be running a phased array, and I'll pick up a few db gain over a dipole(dbd), so that will make up for the loss in the cable. Speaking of the HTX-10, I think I'm going to pick up two spares if Radio Shack winds up going out of business. There should be a big sale on all their radio-related gear when they liquidate. I'll be listening to 28.412 on Sunday for sure. If I hear u guys decently on the indoor antenna, I'll just put the HTX-10 in my car and see if you guys can hear me . That might work until I get the phased array built and installed. I'll be on 10 daily until the sunspot cycle says no, and I'll try to operate on 28.412, so listen up for me during the day, if you're around. Even if I never hear and work you guys, I'll still have a lot of fun on 10, for sure. Sorry to hear about the F-layer skip messing u guys up on CRR, and I've heard it happening watching spitfire's videos on YouTube and on spew. Here's a dumb idea: everyone xmit on 13, but everyone also listens to spitfire's spew stream while he has his array swung to the north east . I don't know if the delay would be too hard to live with, but you'd think that would alleviate a lot of interference . Where there is a will there is a way . Just call this solution "Coonass ingenuity." . I really doubt this will work, but I'd be curious to see how bad the delay was and how people would react to doing things that way. And speaking of spew, I've noticed that your midland rig you use on the stream seems to be picking up some kind of sputtering hash when nobody is transmitting, SB. It's about S3 and jumps up to S4 or so constantly. Any idea on why that is happening? I've tried to change to spitfire's stream to listen, but he doesn't seem to run the stream very often. (I have never been able to connect to it.) 73, Randy AB5NI
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Post by ab5ni on Oct 22, 2014 11:52:39 GMT -5
3db of loss is a bit high. I'd opt for a different type of cable. RG213 is about half the loss. LMR-400 even less. I agree; I wouldn't use anything less than LMR-400. I've never even heard of LMR-400. Must be too rich for my blood . 73, Randy AB5NI
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Post by ab5ni on Oct 22, 2014 12:35:45 GMT -5
The only problem with making wire antennas for CB is that unless you have a really tall tree (or other tall structure) to hoist the antenna up by, it's hard to mount them vertically and get any usable height. But I may have to try this antenna design as I do have one really tall tree to hoist it up by, and it might just work better than my SWR challenged 3 element beam on 10 meters. Fortunately, I have an 80' pine tree right outside of my bedroom window. Should make for a decent antenna location. Going to hoist up a piece of pvc and hang two J-Poles off the thing and anchor the pvc to the ground. Hope that works. 73, Randy AB5NI
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Post by ab5ni on Oct 22, 2014 12:40:45 GMT -5
Note on the PDF it shows the shield connected to the same side of the ladder line as the radiating wire. According to the web page below doing that will distort the radiation pattern, but leave the SWR unchanged. The web page below says to connect the center conductor to the side with the long radiating wire attached. See below; www.w8ji.com/end-fed_vertical.htmNight Ranger Tom, W8JI, is a very knowledgeable engineer. He really knows what he's talking about with linear amplifiers and antennas. I used to talk to him often in the 80's on 160 an 80 Mtrs. He's probably still hanging out on 160 during the winter months. If he has anything to say about an amp or antenna, I'd listen up and listen well. 73, Randy AB5NI
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Post by ab5ni on Oct 22, 2014 15:27:37 GMT -5
Sounds to me like you've just chosen your new CB handle......... Nice! There is only one problem: I don't know if you can say Coonass on the radio and not get in trouble. Well, I know u can say ass and get away with it, but Coonass is considered to be a vulgar, derogatory word. When we call each other that, it's like blacks calling each other the N-word. Well, except we don't mind anyone calling us that like they do. Cajun's love to make fun of themselves and take all insults in stride. (Shrug.) Maybe I can be "Coon" or "Coonie" with Coonass implied . That would work. 73, Randy AB5NI
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Oct 22, 2014 17:57:02 GMT -5
Note on the PDF it shows the shield connected to the same side of the ladder line as the radiating wire. According to the web page below doing that will distort the radiation pattern, but leave the SWR unchanged. The web page below says to connect the center conductor to the side with the long radiating wire attached. See below; www.w8ji.com/end-fed_vertical.htmNight Ranger It makes more sense to connect the center contact to the "long" side of the antenna. I was wondering why the shield was going there, but when it comes to homebrew antennas, I'm far better off with radios and amps......
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Sandbagger
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Post by Sandbagger on Oct 22, 2014 18:01:24 GMT -5
I agree; I wouldn't use anything less than LMR-400. I've never even heard of LMR-400. Must be too rich for my blood . LMR-400 is used mostly for VHF and higher freqs due to its low loss. Then there is LMR-600 which is better yet, but thicker.... www.timesmicrowave.com/downloads/tech/LMRIntl.pdf
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Post by ab5ni on Oct 22, 2014 18:05:01 GMT -5
It makes more sense to connect the center contact to the "long" side of the antenna. I was wondering why the shield was going there, but when it comes to homebrew antennas, I'm far better off with radios and amps...... To hell with it, SB -- purchase one of those 3CX-10000A amps and be done with that stuff! 73, Randy AB5NI
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Post by cbrown on Oct 23, 2014 8:47:22 GMT -5
I've never even heard of LMR-400. Must be too rich for my blood . I've been using TMS cables since the 1970's, my elmer got me using them instead of the cheap cable that was around at the time. The company has been in business since 1948. I'm amazed you never heard of them. With a -3dB loss in the feed-line, you'll need at least a 3 dB gain in the antenna to be back to your original power. Take my advice and change your feed-line, that way any gain you get from your antenna is a positive you can use instead of making up for feed-line loss. Just my opinion.
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Sandbagger
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Post by Sandbagger on Oct 23, 2014 9:08:17 GMT -5
Tom, W8JI, is a very knowledgeable engineer. He really knows what he's talking about with linear amplifiers and antennas. I used to talk to him often in the 80's on 160 an 80 Mtrs. He's probably still hanging out on 160 during the winter months. If he has anything to say about an amp or antenna, I'd listen up and listen well. 73, Randy AB5NI I was surprised at just how much of an issue the common mode currents were on a J-pole. He also does not seem to be much of a fan of the Imax-2000. On that subject, I will have to take issue with his findings. Based on his model patterns the Imax should be a far worse performer than empirical data would suggest. The people who have them seem to get out well, and I can't believe that all of them were "lucky" enough to pick the optimal height and feedline length, where the antenna supposedly works semi-adequately. I can remember Gene "Ol' zero-five" running both an Imax and a Maco 5/8th wave GP at different times on the same mast. Yes, the Maco was better (and had less coaxial radiation RF feedback) in signal, but not by a whole lot, maybe a needle's width. There wasn't much difference in signal between Pete's "up-the-hill" 5/8th wave GP and his Imax antennas on his house. But I do agree than running an end-fed vertical without proper decoupling is asking for trouble. I truly miss the large metal monsters that we had back in the 70's.
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Post by ab5ni on Oct 23, 2014 18:24:16 GMT -5
I was surprised at just how much of an issue the common mode currents were on a J-pole. He also does not seem to be much of a fan of the Imax-2000. On that subject, I will have to take issue with his findings. Based on his model patterns the Imax should be a far worse performer than empirical data would suggest. The people who have them seem to get out well, and I can't believe that all of them were "lucky" enough to pick the optimal height and feedline length, where the antenna supposedly works semi-adequately. I can remember Gene "Ol' zero-five" running both an Imax and a Maco 5/8th wave GP at different times on the same mast. Yes, the Maco was better (and had less coaxial radiation RF feedback) in signal, but not by a whole lot, maybe a needle's width. There wasn't much difference in signal between Pete's "up-the-hill" 5/8th wave GP and his Imax antennas on his house. But I do agree than running an end-fed vertical without proper decoupling is asking for trouble. I truly miss the large metal monsters that we had back in the 70's. Admittedly, empirical data is hard to argue, and you have to remember that guys like Tom are almost always "by the numbers" individuals. Personally, I think the truth lies somewhere between the two. I've "listened" to Pete's Imax array on his videogates, and they seem to play very well. Nobody seems to have a problem hearing him, and he usually works what he hears. BTW, I hear u guys use the term "Zero Five" quite often, and , via context, I take it that a "Zero Five" is along the same lines as a Ham Lid? 73, Randy AB5NI
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Sandbagger
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Post by Sandbagger on Oct 23, 2014 21:15:46 GMT -5
Admittedly, empirical data is hard to argue, and you have to remember that guys like Tom are almost always "by the numbers" individuals. Personally, I think the truth lies somewhere between the two. I've "listened" to Pete's Imax array on his videogates, and they seem to play very well. Nobody seems to have a problem hearing him, and he usually works what he hears. BTW, I hear u guys use the term "Zero Five" quite often, and , via context, I take it that a "Zero Five" is along the same lines as a Ham Lid? 73, Randy AB5NI Yes, I've read many of Tom's contributions on ham forums. He is without a doubt, one of the most book smart guys I've ever run across. His account of the theory involved is hard to argue with. But like I've often run across in my years of playing with this stuff, sometimes things just defy what the theory says it should do. I like to rely "on the numbers" as well (especially when it comes to debates about amplifier power claims), but once in a while I will get shown things that just don't make sense, and I'm left scratching my head. I guess that's one of the reasons I love this hobby. There are so many variables that you really can't predict how something will ultimately work out, and that's half the fun. "Zero-five" (or zero-fiving") is a new technical term for when someone fries a piece of equipment. It is derived from an old friend of ours who moved to Florida a couple of years back by the name of Gene. His skip numbers were "zero-five", and he was someone who loved building big tube amps, and then often summarily cooking them from pushing them too hard battling with the locals who he didn't get along with. So when someone overdrives their amp and it goes up in a cloud of smoke, he "zero-fived" it.
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Post by ab5ni on Oct 23, 2014 21:49:47 GMT -5
Yes, I've read many of Tom's contributions on ham forums. He is without a doubt, one of the most book smart guys I've ever run across. His account of the theory involved is hard to argue with. But like I've often run across in my years of playing with this stuff, sometimes things just defy what the theory says it should do. I like to rely "on the numbers" as well (especially when it comes to debates about amplifier power claims), but once in a while I will get shown things that just don't make sense, and I'm left scratching my head. I guess that's one of the reasons I love this hobby. There are so many variables that you really can't predict how something will ultimately work out, and that's half the fun. "Zero-five" (or zero-fiving") is a new technical term for when someone fries a piece of equipment. It is derived from an old friend of ours who moved to Florida a couple of years back by the name of Gene. His skip numbers were "zero-five", and he was someone who loved building big tube amps, and then often summarily cooking them from pushing them too hard battling with the locals who he didn't get along with. So when someone overdrives their amp and it goes up in a cloud of smoke, he "zero-fived" it. I have also followed Tom's writings for many, many years, and he's definitely one of the brighter guys I've met in amateur radio. If I remember correctly, he was one of design engineers for Dentron along with Denny. I think he also did some work for Amp Supply, improving and fixing some designs made by another engineer. Another would be Marty, WB0ESV, whose written many articles for the ham rags over the years. Currently, I'm following a guy on YouTube named Pete Juliano. I love the way he makes all his radios in a "modular, reusable circuit" format. As far as zero-fiving gear goes, I know the type . Fortunately, I don't think I've ever zero-fived something, but I have had amps let lose a few supply electrolytics that I knew were close to giving up the secret smoke hidden inside. That was more out of laziness then anything else, but I guess when push comes to shove, I have zero-fived a couple of things . 73, Randy "Zero Five Coon" From the B.Y.U...GET BACK!!!
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Post by ab5ni on Oct 23, 2014 22:52:14 GMT -5
I've never even heard of LMR-400. Must be too rich for my blood . I've been using TMS cables since the 1970's, my elmer got me using them instead of the cheap cable that was around at the time. The company has been in business since 1948. I'm amazed you never heard of them. With a -3dB loss in the feed-line, you'll need at least a 3 dB gain in the antenna to be back to your original power. Take my advice and change your feed-line, that way any gain you get from your antenna is a positive you can use instead of making up for feed-line loss. Just my opinion. Like I said before, CB: I already have the RG-8X, so I'm going to just use that; however, if I build a new antenna I'll be sure to take a look at the LMR-400 cable. It will also be nice to use that cable on 6 Mtrs. Anywho, your words are not falling on deaf ears, my friend . 73, Randy AB5NI
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