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Thread: MCLAPP vertical 8-bay build, slight increase in pole height and dedicated DX'ing TV?

  1. #1
    Join Date
    Jul 2016
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    Rogersville MO
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    Default MCLAPP vertical 8-bay build DONE and DEPLOYED FOR TESTING!!

    I'm thinking about building an MCLAPP design vertical 8-bay with a reflector and going up another 10 feet with the antenna pole. This will "triple" my array (in that my present 4-bay is unreflected) and put the top of the antenna about 38 feet off the ground, as opposed to 24 feet now.

    I'm also thinking about keeping the M4 to feed the house, put up the new antenna/pole right behind the living room TV and make it a dedicated DX'ing TV.

    Anyways Jim Thomas encouraged me to research the CM4228. I'm not sure if I'm reading it right, but it looks like the M8 I propose to build mostly outperforms the "hot" CM4228 in gain. I know that's not all that makes a good antenna, and there's still things I don't understand, like "front to back ratio", "dB above noise floor" and how all of it affects antenna performance.

    I'm hoping someone wouldn't mind to help me understand these things and maybe help check my research. I'd really like to get the best bang for my buck if I'm going to build another antenna. This time it will be precise with nothing left to chance. That's a lot of work and I'd like to maximize the reward.

    Besides........Jim's new antenna is vacuuming up all the DX around here like Hoover cleans a rug! lolz

    Thanks everyone
    Last edited by DXseekerMO; 07-19-2017 at 07:41 PM.

  2. #2
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    Default

    Did I ask too broad of a question? lol

  3. #3
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    Feb 2006
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    Your antenna, needs a "reflector". That will make it directional , also you will have front to back ratio. Without a reflector, your antenna, will pick up, in all directions. Jim's ant. has 12 elements, but it has a large reflector. Makes a big difference.
    CM put in a lot of research, in developing their antennas. ALL of them, have reflectors ! Hard to improve on their designs...

    Gary H.

  4. #4
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    Yeah it does need a reflector, that's for sure. What is front to back ratio, and is there an ideal?

    I'm sure CM probably does the finest research too, and everyone speaks well of the 4221, but according to MCLAPP's research his reflected M4 shows more gain overall than even a "hot" CM4221 with some mods. There's no doubt about how good Jim's antenna and mods are, it's a signal funnel!

    There's also an antenna called a "FF4" (free-form 4-bay) and an "FF6". These show even more gain than the MCLAPP M4 but require the user to know the incoming angle of the signal and match the angle of the antenna to it when mounting it to the pole. I think this would make the FF series antenna less desirable for DXing. I would like to put up some research info but I don't want to step on anyone's toes or violate someone's copyright. I'm also not knocking the CM antennas.

    Maybe it would be easier on all if I should just ask "what am I missing" (besides the technical knowledge I need to understand which way to go) and "does anyone here know anything about or have experience with MCLAPP design antennas?"

    Thanks for the reply Gary!

  5. #5
    Join Date
    Feb 2006
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    I think k6sti in Calif., would be the person, to ask about F/B ratio, gain etc. He is able to model antennas and see whats going on. He has Posts in Antenna Forum and DX Equip. Forums.
    I'm not famililar with the FF antennas.

    Gary H.

  6. #6
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    I'm not familiar with the FF either. Sounds like k6sti is a good person to ask, thanks for the tip Gary! I've been on forums where one can shout out to a member using @ before their screen name. Is there a way to do that here, or just contact through one of their posts/PM?

    Just one more question for the TVDX folks......if you were asked for an antenna recommendation specifically for serious hard core TVDX purposes would it be the modified CM4221, and should I just take the blinders off and go that way?

    Thanks.

  7. #7
    Join Date
    Jul 2005
    Location
    Springfield, Missouri
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    K6STI (Brian) hasn't been on the forums here for a couple months now. Not sure what's going on that he doesn't come back around.

    I would go to Solid Signal and look at the top-of-the-line TV antennas they are selling, do some research on them and then maybe ask questions about specific models. The reason the 4221 and 4228 were so popular was because by virtue of design, they pulled hi VHF signals in, in addition to the UHF they were designed for. The reason for hi VHF reception was because of the screen reflector design. And that contributes to the F-to-B ratio. The NEW 4221's and 4228's were redesigned and CM quit using the screen on the new design. They now use a horizontal bar reflector background and it doesn't even affect hi VHF frequencies the same as the original design. That seriously changed the performance of high VHF reception, although the 4221 and 4228 were designed for UHF.

    Solid Signal is a source for TV antennas as mentioned....
    http://www.solidsignal.com/

    Also the other popular route to go is Antennas Direct, which is a St. Louis antenna manufacturer...
    https://www.antennasdirect.com/

    Very similar to the McLapp would be building "Big Bertha", the DB8 antenna....
    http://www.instructables.com/id/Buil...na-Big-Bertha/
    Jim Thomas
    Springfield, MO

    Making FM Dxing more fun than a barrel of monkeys!

  8. #8
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    Default Decision made!

    So after taking a look at Jim's links and adding some of my own "research" I've made a decision. I'll try not to be wordy with my reasons.

    Ultimately for me I prefer to build something from nothing. I just like that stuff! If it isn't antennas it's special tools out of brass pipe or taking a free 1989 mobile home and turning it in to a place you couldn't buy for under 70 grand....and for half that!

    In the final equation.....who cares what antenna has how much gain! For me it's all about the adventure.....and using something I built with my own two hands to do something I never thought I'd be able to do again....that is view TV signals from far away. I really thought DX'ing was gone when they switched everything to digital. In some ways it's like running across an enjoyable old friend.

    For those reasons I will build the MCLAPP vertical 8-bay using his instructions and great care will be taken to follow them precisely and to the letter. It will also be cool to meet Jim Thomas and learn from his experience, as he offered to come out, meet me and help with the build!

    So now that's settled. I can stop asking questions and just enjoy! Thanks for your replies and patience everyone.

  9. #9
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    Jul 2016
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    So I went and did it…the monster 8-bay “Megatenna” is built and deployed for testing! Click image for larger version. 

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ID:	20719Here are some highlights of the build:

    As you can see from the pictures it’s a “mono-spine” design. Instead of bolting the insulators to a single long pole I stood eight pieces of square aluminum tubing up on the backbone, place the insulators on top of that and used one long carriage bolt to hold each of the stand-offs and insulators to the backbone. Click image for larger version. 

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    Each end of the aluminum stand-offs were hand filed to exactly square so they stand up perfectly vertical, thus helping to keep the insulators centered and perpendicular to the pole. The insulators are some kind of acrylic counter top material I had laying around.

    The phase lines are 10ga copper. After straightening the wires all of the whisker attachment points, center feed point and location of the bends were precisely marked. After bending they were all final shaped together to ensure they are all identical. The ends of each phase line were cut perfectly square and they’re all identical length.

    The whiskers are 8ga, or 1/8”dia copper wire all precisely cut to the exact same length, were bent around a ¼” fastener then further bent on a jig I made to shape them identically. A piece of wire was taped between each end of the whisker to keep them 5 ½” apart on the ends. The exact center was marked on the tape. Click image for larger version. 

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    Assembly was a PAIN with the “mono-spine” but its all together now.

    I’ll be updating further later, but let me tell you…..last night I logged 4 stations 82 miles away with signal strengths as much as the local stations that transmit 11 miles away. This also happened the night before. Tonight I’ve logged 4 stations 165 miles away with a very respectable signal level.
    All of this is with the antenna mounted 14” above the ground on a temporary pole!

    Let me mention I am in a good DXing location here, 1420 feet above MSL so I know this helps…..but DANG!!!!!!!!!! IT’S NOT EVEN ON THE POLE YET!!!!!!!!!!!!!

  10. #10
    Join Date
    Feb 2012
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    Southeastern Louisiana
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    Thanks for the Update and Pictures of the finished Antenna. Looks great & professionally made. Keep us updated on what DX you receive on the Antenna.

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