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Post by Night Ranger on May 7, 2011 10:08:26 GMT -5
I've been wanting to try something different for the CB band, and I've looked through the ARRL Antenna handbook for years for various projects. Unfortunately I was living in an apartment for the past few years, so my antenna projects were limited. Last summer I bought a house with plenty of woods around it and very few neighbors, so it's time for my antenna farm.
My first venture was the standard dipole followed by a delta loop. Both antennas performed well with no noticeable difference between the two. My next venture was an extended double zepp antenna for the CB band. The extended double zepp noticeably out performed both the 1/2 wave dipole and the full wave loop, and when hung with the wires running north and south it noticeably cut down on the hispanic skip coming from the south.
My latest antenna adventure is a 4 element broadside array also known as a Lazy H antenna. My current observation is when listening to close in skip (South Carolina to Arkansas) the dipole out performs the 4 element broadside array due to the higher angle of radiation of the dipole at equal height to the 4 element broadside array. However when listening to east coast to west coast of North America (2000 miles plus) skip the 4 element broadside array sometimes beats the dipole. (See my updated reply below).
I'm using 5/8th wave spacing between the top and bottom elements. The top and bottom elements are being center fed with 450 ohm ladder line back to an antenna tuner with a 4:1 balun inside the tuner. According to the ARRL Handbook the 4 element broadside array should have about 6.7 db gain over a half wave dipole when using 5/8ths wave spacing between the top and bottom elements. The angle of radiation at it's current height (40 + feet at the top wire) should be about 10 to 12 degrees above the horizon.
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Sandbagger
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Post by Sandbagger on May 7, 2011 12:59:42 GMT -5
I've been wanting to try something different for the CB band, and I've looked through the ARRL Antenna handbook for years for various projects. Unfortunately I was living in an apartment for the past few years, so my antenna projects were limited. Last summer I bought a house with plenty of woods around it and very few neighbors, so it's time for my antenna farm. My first venture was the standard dipole followed by a delta loop. Both antennas performed well with no noticeable difference between the two. My next venture was an extended double zepp antenna for the CB band. The extended double zepp noticeably out performed both the 1/2 wave dipole and the full wave loop, and when hung with the wires running north and south it noticeably cut down on the hispanic skip coming from the south. My latest antenna adventure is a 4 element broadside array also known as a Lazy H antenna. My current observation is when listening to close in skip (South Carolina to Arkansas) the dipole out performs the 4 element broadside array due to the higher angle of radiation of the dipole at equal height to the 4 element broadside array. However when listening to east coast to west coast of North America (2000 miles plus) skip the 4 element broadside array is toasting the dipole. I'm using 5/8th wave spacing between the top and bottom elements. The top and bottom elements are being center fed with 450 ohm ladder line back to an antenna tuner with a 4:1 balun inside the tuner. According to the ARRL Handbook the 4 element broadside array should have about 6.7 db gain over a half wave dipole when using 5/8ths wave spacing between the top and bottom elements. The angle of radiation at it's current height (40 + feet at the top wire) should be about 10 to 12 degrees above the horizon. See the YouTube video below to see my homemade 4 element broadside array. You may need to kick up the resolution of the YouTube video to 720 HD to see the green insulated wires against the green trees in the back ground. www.youtube.com/watch?v=bkDh5ilaFzAI think you're also learning the fundamental rule when it comes to antennas, and that is that there is no such thing as a "one size fits all" antenna system. Each type has a particular characteristic which makes it more desirable in some conditions, but less so in others. That why most HF hams really do have an antenna "farm", so that they can switch to the one which works the best for the particular station and condition they have at that time.
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Post by spitfire441 on May 8, 2011 2:50:58 GMT -5
There must be something in the "air"waves....I have been thinking along those lines for a gain antenna on the lower HF bands. I recently picked up a copy of the 1960 Radio Amatuers Handbook, by the ARRL. Not only does it have some good tube therory and practice, cool (read easy) antenna projects as well as some very interesting stuff on VHF/UHF even 1296 and not to forget ways of getting on our underutilized awsome 222mhz band!!!. It also has a small radio cataloge in the back pages that is cool to look at. Anyway the lazy "H" antenna was one I was considering. All I would have to do is make a copy of my existing 160m doublet and change to a feed in the center of both.(I love windowline). I then got to looking at some of the VHF designs of the time,yagis were not widely used yet, many were curtain arrays, phased dipoles in front of a set of reflectors, or screen. I then scaled one up for 11-10 meters and got to looking at some of my trees on 3 acres, and I will be trying some of these designs out. Feeding and phasing wire antennas with 450 ohm window line is a snap. Can you say 14.5 Dbd gain over a diple on 11m? (from wire!)
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Sandbagger
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Post by Sandbagger on May 8, 2011 8:53:47 GMT -5
There must be something in the "air"waves....I have been thinking along those lines for a gain antenna on the lower HF bands. I recently picked up a copy of the 1960 Radio Amatuers Handbook, by the ARRL. Not only does it have some good tube therory and practice, cool (read easy) antenna projects as well as some very interesting stuff on VHF/UHF even 1296 and not to forget ways of getting on our underutilized awsome 222mhz band!!!. It also has a small radio cataloge in the back pages that is cool to look at. Anyway the lazy "H" antenna was one I was considering. All I would have to do is make a copy of my existing 160m doublet and change to a feed in the center of both.(I love windowline). I then got to looking at some of the VHF designs of the time,yagis were not widely used yet, many were curtain arrays, phased dipoles in front of a set of reflectors, or screen. I then scaled one up for 11-10 meters and got to looking at some of my trees on 3 acres, and I will be trying some of these designs out. Feeding and phasing wire antennas with 450 ohm window line is a snap. Can you say 14.5 Dbd gain over a diple on 11m? (from wire!) I think it has to do with living on a fair sized piece of property with lots of trees. Antennas seem to "grow" much better under those conditions..... ;D
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Post by Night Ranger on May 8, 2011 21:11:17 GMT -5
Well California, Arizona and Nevada skip rolled in for a little while today, and I got to do alot of A/B testing with the dipole verses the Lazy H. The bad news is the dipole consistently had stronger received signals than my Lazy H. Hmmm....Something tells me there is something up between text book antenna and the real world antenna when it comes to a Lazy H on 27 MHz. I've checked and re-checked my measurements and the Lazy H is exactly like the text book says. Of course the text book says you can make an extended double zepp and feed it with ladder line back to the antenna tuner and it should work. Real world proved that set-up sucked on 27 MHz. The extended double zepp did not come to life until I used slightly less than a 6 foot piece of 450 ladder line as a matching transformer back to a 1:1 balun hooked to coax. I don't remember the exact length. Anyway I'm going to try the same trick with the Lazy H tomorrow and see if the promised 6+ dbd gain actually comes to pass. On the transmit side the Lazy H is getting in to the west coast, but I suspect something is up in the real antenna world verses the text book. More updates to come.
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Sandbagger
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Post by Sandbagger on May 9, 2011 7:21:53 GMT -5
Well California, Arizona and Nevada skip rolled in for a little while today, and I got to do alot of A/B testing with the dipole verses the Lazy H. The bad news is the dipole consistently had stronger received signals than my Lazy H. Hmmm....Something tells me there is something up between text book antenna and the real world antenna when it comes to a Lazy H on 27 MHz. I've checked and re-checked my measurements and the Lazy H is exactly like the text book says. Of course the text book says you can make an extended double zepp and feed it with ladder line back to the antenna tuner and it should work. Real world proved that set-up sucked on 27 MHz. The extended double zepp did not come to life until I used slightly less than a 6 foot piece of 450 ladder line as a matching transformer back to a 1:1 balun hooked to coax. I don't remember the exact length. Anyway I'm going to try the same trick with the Lazy H tomorrow and see if the promised 6+ dbd gain actually comes to pass. On the transmit side the Lazy H is getting in to the west coast, but I suspect something is up in the real antenna world verses the text book. More updates to come. Well, if the antenna is constructed properly, and it matches up as expected, then it should be doing what's designed to do. The problem with comparing antennas using DX as the test bed, can be frustrating, because conditions never stay the same for very long. Angle of radiation may also be a factor. When the F-layer opens up and you start hearing Europe, Africa, and longer shots like that, you may find that the lower radiation angle antennas will work better.
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Post by Night Ranger on May 9, 2011 20:26:54 GMT -5
I pulled the antenna down this afternoon, and removed any twist in the center fed 450 ladder line, and I made sure the top and bottom elements were being fed in phase. The phasing was correct. I also verified connectivity between the top left and bottom elements and between the right top and bottom elements. It was all good. I also verified there was no connectivity between the left and right elements. The array is broadside towards California. Some sporadic E skip from the north rolled in from New York over to Michigan. I pointed my dipole broadside to the north and compared the signals. The west facing Lazy H displayed the expected null to the North.
I'll try a 1/4 wave 450 ohm ladder line matching section and a 1:1 balun tomorrow. I'll probably end up using about half of that. I'm not sure what the impedance of the antenna is with 5/8ths wave spacing between the top and bottom elements, so I'll just have to find the best match by trail and error.
In it's current configuration a dipole at 30 feet consistently out performs the Lazy H antenna at 40+ feet. The Lazy H only consistently broke even with the dipole when listening to a station in Hawaii from South Carolina. There was one station in Arizona that occasionally came in stronger on the Lazy H, but it was never consistent.
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Post by Night Ranger on May 12, 2011 12:54:08 GMT -5
Well I rebuilt the Lazy H, checked all connections with an ohm meter, checked phasing in between the top and bottom elements, and the lowly dipole still out performed the lazy H from 800 miles out to 2500 miles out.
I think the center fed Lazy H with 450 ohm ladder line back to the tuner is an antenna modeling software success, but a real world dud. In my real world A/B antenna comparisons the dipole out performed the Lazy H.
I may give the Lazy H one more try by end feeding it with a 180 degree twist in the 450 ohm connecting line between the top and bottom elements, and a 1/4 wave matching stub. An old codger ham friend claimed the end fed version of the Lazy H was "a skip magnet".
The good news is my home made extended double zepp wire antenna broadside to California with it's narrow east/west lobes and north/south nulls helped bring in California and simultaneously null out the AM carriers and spanish speaking skip coming out of Mexico, Central America, and South America.
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Post by Night Ranger on Jun 3, 2011 9:38:39 GMT -5
Woohoo! I found the problem with my Lazy H antenna! I had the 450 ladder line feeding the center of the antenna going away from the Lazy H at a 45 degree angle. Apparently the Lazy H antenna is very picky about how the 450 ohm ladder line exits away from the center of the antenna. The 45 degree ladder line exit angle was causing the radiation pattern from the Lazy H to be skewed in the direction of the ladder line and in the exact opposite direction for the opposite main lobe. In other words even though the antenna was broadside to the east and west the main lobes of gain were skewed to the northwest and southeast.
The main clues came when a station in the Caribbean gave me a 20 over S9 signal report. That direction should have been in a null off the side of the antenna. A few days later skip rolled in from Iowa (northwest), and I noticed received signal gain in that direction when I compared the Lazy H antenna to a 1/2 wave dipole facing to the east and west. I realized the antenna radiation pattern was skewed, and I went outside to examine the antenna. Once I repositioned the ladder line so that it exited away from the antenna at a 90 degree angle (perpendicular to the plane of the antenna) the radiation pattern of the antenna began to perform more closely to what the ARRL handbook stated it should be. Later that day stations in Arkansas, which is broadside to the antenna, were begging for mercy. : ) I'll post a new video of the antenna once I get home.
Night Ranger
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Post by cbrown on Jun 3, 2011 9:49:28 GMT -5
The feedlines like to be 90°. Glad you figured it out, and I look forward to seeing the video.
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Sandbagger
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Post by Sandbagger on Jun 3, 2011 11:37:20 GMT -5
Woohoo! I found the problem with my Lazy H antenna! I had the 450 ladder line feeding the center of the antenna going away from the Lazy H at a 45 degree angle. Apparently the Lazy H antenna is very picky about how the 450 ohm ladder line exits away from the center of the antenna. The 45 degree ladder line exit angle was causing the radiation pattern from the Lazy H to be skewed in the direction of the ladder line and in the exact opposite direction for the opposite main lobe. In other words even though the antenna was broadside to the east and west the main lobes of gain were skewed to the northwest and southeast. The main clues came when a station in the Caribbean gave me a 20 over S9 signal report. That direction should have been in a null off the side of the antenna. A few days later skip rolled in from Iowa (northwest), and I noticed received signal gain in that direction when I compared the Lazy H antenna to a 1/2 wave dipole facing to the east and west. I realized the antenna radiation pattern was skewed, and I went outside to examine the antenna. Once I repositioned the ladder line so that it exited away from the antenna at a 90 degree angle (perpendicular to the plane of the antenna) the radiation pattern of the antenna began to perform more closely to what the ARRL handbook stated it should be. Later that day stations in Arkansas, which is broadside to the antenna, were begging for mercy. : ) I'll post a new video of the antenna once I get home. Night Ranger Interesting findings, and easy to understand, once you realize the forces at work. That's the fun of playing with antennas. I just wish I had more real-estate to play in that sandbox
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Post by Night Ranger on Jun 6, 2011 8:33:50 GMT -5
I'm still tinkering with the Lazy H antenna and trying to consistently get the 5.9 db gain claimed by the ARRL handbook. So far the gain I'm seeing is not consistent, but I'm not finished with the antenna design yet. Here are a few things I've learned and seen in real world antenna installations when dealing with the Lazy H antenna and 450 ladder line; 1) The ladder line needs to come away from the antenna at a 90 degree angle from the antenna (left or right) or it will skew the radiation pattern of the antenna in the direction of the feed line departure and in the opposite direction. 2) If the ladder line droops too close to the phasing line as it comes away from the center of the Lazy H the impedance goes up noticeably which will cause a more extreme setting on the antenna tuner to be used to match the antenna to the transmitter. 3) The length of the ladder line affects the SWR presented to the antenna tuner with some lengths causing the match to be beyond what the antenna tuner can match. 4) Avoid cutting the ladder line to multiples of a 1/2 wave length as it is more more likely to cause problems with common mode RF flowing on the ladder line. Keep in mind the velocity factor of the ladder line when calculating a 1/2 wave length and it's multiples. My ladder line manufacturer (The Wireman) states a velocity factor of .91. After randomly trying several different lengths of ladder line back to the antenna tuner with unsatisfactory results, I cut my ladder line in between a 1/2 wave multiple, and the antenna tuner more easily tuned the Lazy H. See the web page below for advice on using ladder line; www.athensarc.org/ladder.asp5) The center fed Lazy H is rather finicky compared to a coax fed 1/2 wave dipole, a coax fed extended double zepp antenna with a 450 ohm matching section down to a 1:1 balun, or a 300 ohm ohm twin lead fed delta loop. 6) The antenna tuner setting that receives the strongest signal from the Lazy H antenna may not be the same setting where the antenna tuner gets the best match on transmit. Unfortunately this means some signal loss on the received signal when the antenna tuner is tuned for the best match on transmit. I have been using the following horizontally polarized wire antennas cut for the same frequency for A/B/C/D gain comparisons; 1) 1/2 wave dipole 2) extended double zepp 3) delta loop 4) lazy H So far, the biggest bang for the buck and effort required to build and install the antenna has been the extended double zepp antenna. This antenna rocks for DX work. The Lazy H is working well also, but it took alot more effort to get it working correctly. I'll post more as I continue to try different things with the Lazy H antenna. See the link below for information on the extended double zepp antenna. Scroll down to section number "13" for a picture and construction details. www.hamuniverse.com/n4jaantennabook.htmlNight Ranger
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Sandbagger
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Post by Sandbagger on Jun 6, 2011 11:21:20 GMT -5
I'm still tinkering with the Lazy H antenna and trying to consistently get the 5.9 db gain claimed by the ARRL handbook. So far the gain I'm seeing is not consistent, but I'm not finished with the antenna design yet. Here are a few things I've learned and seen in real world antenna installations when dealing with the Lazy H antenna and 450 ladder line; 1) The ladder line needs to come away from the antenna at a 90 degree angle from the antenna (left or right) or it will skew the radiation pattern of the antenna in the direction of the feed line departure and in the opposite direction. 2) If the ladder line droops too close to the center phasing line as it comes away from the antenna the impedance goes up noticeably which will cause a more extreme setting on the antenna tuner to be used to match the antenna to the transmitter. 3) The length of the ladder line affects the SWR presented to the antenna tuner with some lengths causing the match to be beyond what the antenna tuner can match. 4) Avoid cutting the ladder line to multiples of a 1/2 wave length as it is more more likely to cause problems with common mode RF flowing on the ladder line. Keep in mind the velocity factor of the ladder line when calculating a 1/2 wave length and it's multiples. My ladder line manufacturer (The Wireman) states a velocity factor of .91. After randomly trying several different lengths of ladder line back to the antenna tuner with unsatisfactory results, I cut my ladder line in between a 1/2 wave multiple, and the antenna tuner more easily tuned the Lazy H. See the web page below for advice on using ladder line; www.athensarc.org/ladder.asp5) The center fed Lazy H is rather finicky compared to a coax fed 1/2 wave dipole, a coax fed extended double zepp antenna with a 450 ohm matching section down to a 1:1 balun, or a 300 ohm ohm twin lead fed delta loop. 6) The antenna tuner setting that receives the strongest signal from the Lazy H antenna may not be the same setting where the antenna tuner gets the best match on transmit. Unfortunately this means some signal loss on the received signal when the antenna tuner is tuned for the best match on transmit. I have been using the following horizontally polarized wire antennas cut for the same frequency for A/B/C/D gain comparisons; 1) 1/2 wave dipole 2) extended double zepp 3) delta loop 4) lazy H So far, the biggest bang for the buck and effort required to build and install has been the extended double zepp antenna. This antenna rocks for DX work. I'll post more as I continue to try different things with the Lazy H antenna. See the link below for information on the extended double zepp antenna. Scroll down to section number "13" for a picture and construction details. www.hamuniverse.com/n4jaantennabook.htmlNight Ranger Ever thought about building a rhombic?
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Post by Night Ranger on Jun 6, 2011 12:11:56 GMT -5
Ever thought about building a rhombic? As of matter of fact I have. These are future antenna projects I am considering; 1) sterba array 2) rhombic 3) V beam 4) wire yagi beam 5) bi-square Night Ranger
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Post by Night Ranger on Jun 8, 2011 8:31:50 GMT -5
DX results for the home made horizontally polarized Lazy H wire antenna in South Carolina aimed to the west coast of the United States on 6/7/2011 on channels 37, 38, and 39 LSB.
Yesterday the skip was rolling in from Southern California, Washington State, Utah, Nevada, Wyoming, Texas, Idaho, New Mexico and Arizona. The Lazy H antenna is aimed just north of west.
I received several good reports coming from Southern California, and especially from states north of Southern California (Nevada, Utah, Washington state, and Wyoming). I also received good reports from Arizona and New Mexico.
The Lazy H consistently out performed the half wave dipole in those directions, and it was much much better at rejecting the AM carriers coming from Mexico, Central America, The Caribbean, and South America. When I switched from the west facing dipole to the west facing Lazy H antenna the stations from the western United States jumped up in signal strength, and most of the AM signals from the south either completely disappeared or fell back to such a small signal level they were no longer an issue.
: )
Night Ranger
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Post by Night Ranger on Jun 8, 2011 20:46:03 GMT -5
I posted a video on YouTube showing my new home made Lazy H antenna for the CB band. It can also be used on 10 meters and 20 meters.
UPDATE: I removed this video and recorded a new one later in this message thread.
Night Ranger
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Post by cbrown on Jun 10, 2011 10:05:16 GMT -5
How well does it load up on 20M?
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Post by Night Ranger on Jun 10, 2011 11:29:28 GMT -5
How well does it load up on 20M? I don't know. I have not tried it on 20 meters. Night Ranger
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Post by homerbb on Jun 10, 2011 11:40:51 GMT -5
I may have to come back and read all of this thread more carefully again. I am considering some kind of curtain array soon. I've done loops and dipoles, an endfed, too. I think I want to attempt one of these.
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Post by Night Ranger on Jun 10, 2011 13:28:13 GMT -5
I may have to come back and read all of this thread more carefully again. I am considering some kind of curtain array soon. I've done loops and dipoles, an endfed, too. I think I want to attempt one of these. I'm about 90% done building a second Lazy H. The first Lazy H is aiming west and east. I have an extended double zepp aiming at the great lake states and South America. I'm going to take down the extended double zepp after work and put the second Lazy H up in it's place. If you want to hear the Lazy H antennas on the air go to channel 38 LSB on weekday evenings and anytime the skip is rolling on the weekends, and listen for 116 Michael in Charleston, South Carolina. Night Ranger
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Post by homerbb on Jun 10, 2011 14:35:25 GMT -5
Will do
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Post by Night Ranger on Jun 12, 2011 5:52:06 GMT -5
I found the remaining problem with my Lazy H antenna that was causing it to under perform. It turns out the stock 4:1 balun in my Dentron MT-3000a tuner stops being a balun by the time it reaches 27 MHz. I found a post on another web site from a ham who was having trouble with his Dentron MT-3000a tuner on 10 meters when trying to use ladder line. He said he had to replace the internal balun to get it to work. When I replaced the balun in mine with another balun the Lazy H antenna lit up! Wow! That antenna rocks now, and the rejection off the sides is petty impressive. The Lazy H antenna is now consistently blowing away the dipole in its favored direction.
I'll post another video showing the difference in receiver gain between the dipole and the Lazy H. I also built a second Lazy H pointing in a different direction. The difference between what the two hear and what they reject is pretty impressive. The difference in received signal strength between the Lazy H and the dipole is also pretty impressive.
Night Ranger
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Post by homerbb on Jun 12, 2011 10:01:05 GMT -5
Now I'm curious for sure . . .
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Post by Night Ranger on Jun 12, 2011 16:49:01 GMT -5
NOTE: The Lazy H antenna is a bi-drectional antenna. It transmits and receives in two opposite directions broadside to the antenna, and it rejects signals coming in to the ends of the antenna. I posted a video on YouTube showing the difference in gain between a dipole and a Lazy H antenna both facing towards Columbia, South America. Station "J.J. 399" in Medellin, Colombia South America is coming in strong to the receiver located in Charleston, South Carolina - U.S.A. I also do an A/B comparison between a Lazy H facing Columbia, South America and a Lazy H facing East and West (West Coast U.S.A. and Bermuda) to show the rejection off the side of the Lazy H. Columbia, South America is not exactly perpendicular to the plane of the east/west facing Lazy H, but the rejection off the main lobe is still substantial. The east/west Lazy H antenna is particularly good at pulling out Channel 38 sideband stations to the west of South Carolina while simultaneously nulling out the AM carriers coming from Mexico, Central America, South America and the Caribbean. www.youtube.com/watch?v=dpIhGNQTtx8Night Ranger
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Post by homerbb on Jun 12, 2011 18:37:39 GMT -5
NOTE: The Lazy H antenna is a bi-drectional antenna. It transmits and receives in two opposite directions broadside to the antenna, and it rejects signals coming in to the ends of the antenna. I posted a video on YouTube showing the difference in gain between a dipole and a Lazy H antenna both facing towards Columbia, South America. Station "J.J. 399" in Medellin, Colombia South America is coming in strong to the receiver located in Charleston, South Carolina - U.S.A. I also do an A/B comparison between a Lazy H facing Columbia, South America and a Lazy H facing East and West (West Coast U.S.A. and Bermuda) to show the rejection off the side of the Lazy H. Columbia, South America is not exactly perpendicular to the plane of the east/west facing Lazy H, but the rejection off the main lobe is still substantial. The east/west Lazy H antenna is particularly good at pulling out Channel 38 sideband stations to the west of South Carolina while simultaneously nulling out the AM carriers coming from Mexico, Central America, South America and the Caribbean. www.youtube.com/watch?v=dpIhGNQTtx8Night Ranger I'll read up on it some and then see whether I can pull it off on my place.
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Jun 13, 2011 6:24:51 GMT -5
I found the remaining problem with my Lazy H antenna that was causing it to under perform. It turns out the stock 4:1 balun in my Dentron MT-3000a tuner stops being a balun by the time it reaches 27 MHz. I found a post on another web site from a ham who was having trouble with his Dentron MT-3000a tuner on 10 meters when trying to use ladder line. He said he had to replace the internal balun to get it to work. When I replaced the balun in mine with another balun the Lazy H antenna lit up! Wow! That antenna rocks now, and the rejection off the sides is petty impressive. The Lazy H antenna is now consistently blowing away the dipole in its favored direction. I'll post another video showing the difference in receiver gain between the dipole and the Lazy H. I also built a second Lazy H pointing in a different direction. The difference between what the two hear and what they reject is pretty impressive. The difference in received signal strength between the Lazy H and the dipole is also pretty impressive. Night Ranger I'm glad you found the last of your issues. Something just wasn't working out as it should. But the lesson here is that you can't take any part of your setup for granted. But I am shocked that Dentron used an inferior balun in a product that would be typically employed from 160 thru 10 meters. That's just unacceptable engineering there.
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Post by Night Ranger on Jun 13, 2011 8:04:24 GMT -5
This is the Eham.net post from the other ham that discovered the problem with the built in 4:1 balun in the Dentron MT-3000a. My experience with the internal 4:1 balun on my Dentron MT-3000a antenna tuner on 27/28 MHz supports his claim.
Night Ranger
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Dentron MT-3000a Tuner review on Eham.net by K8JS
K8JS Rating: 3/5 Feb 22, 2004 00:59
Basically Is OK, but not the best Tuner Out There Time owned: more than 12 months
I bought mine NEW back in the 1970's and had it for several years. At the time I ran Yaesu FT-101 & a Heath SB-220 though it, all bands, from 160 thru 10. Early-on, after the warranty expired, those unique push button switches became "flakey" to operate and from then-on required me to be VERY careful when operating them, else the exposed rectangular button covers would pop out and land on the operating desk. The horizonatally mounted coil developed a slight downward "sway back" shape because after awhile the SB-220's RF power overheated it and softened the clear plastic coil formers. (This gross overheating was cured by removing the grounded coil bracket that contacted the chassis, then I steel-wooled the bracket and chassis contact area, then bolted them back together again.) I also ran balanced feedline antennas at that time, and discovered that the built-in balun was badly UN-balanced at it's "balanced" port for 10 thru 20 meters. To help remedy that problem I had to replace it with a physically larger, and much superior "Super Balun" from Palomar that barely physically fit within the tuner's chassis. So - with correcting the coil's grounded end making a better contact to the chassis, replacing the unit's inferior balun, and gingerly operating those flakey rectangular switched, I was able to continue to use that otherwise very nice tuner for several more years.
---John, K8JS ===========================================
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Post by cbrown on Jun 13, 2011 8:37:12 GMT -5
I don't know. I have not tried it on 20 meters. Ah. I guess the specs say it'll load on 20M then.
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Post by Night Ranger on Jul 8, 2011 7:18:10 GMT -5
I posted this video in another message thread, but for those reading this thread I have a YouTube video of me using the finished Lazy H wire antenna at about 50 feet up at the top wire coming in via skip to Sandbagger's live CB feed in Pennsylvania, U.S.A. I am located near Charleston, South Carolina U.S.A. Video showing my 3 Lazy H antennas for 14 MHz to 30 MHz www.youtube.com/watch?v=qvO_PnI9i7cNight Ranger using the home made Lazy H antenna coming in via skip from Charleston, South Carolina to Pennsylvania on channel 13 AM. Thanks to Sandbagger's Spew Radio live CB feed. www.youtube.com/watch?v=I0hyFuILvvINight Ranger/South Carolina 116 using the home made Lazy H antenna coming in via skip from Charleston, South Carolina to Milwaukee, Wisconsin on channel 38 LSB. Thanks to World Radio 989 for recording this video. www.youtube.com/watch?v=uhKH-SWnNGoNight Ranger checks in to the Classic Radio Roundup via skip using the home made Lazy H antenna www.youtube.com/watch?v=UKeh2WTDpOM&feature=relatedNight Ranger / 116 South Carolina on sideband
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Post by Night Ranger on Nov 19, 2011 11:03:21 GMT -5
Unit 106 in England was kind enough to record a video of me using my home made Lazy H wire antenna coming in skip to the United Kingdom on channel 39 LSB. I was running about 1 KW. : ) "116 Mr. Michael. S. Carolina, USA" www.youtube.com/watch?v=bEvzEQsRdkoI reciprocated and recorded him coming in to South Carolina. This is my recording of the same conversation. www.youtube.com/watch?v=eQHWMra7oJ8Night Ranger
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