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Thread: 40 phone was good to me tonight!

  1. #11
    plenty of extra room "down his pants"
    ElevenBravo's Avatar
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    OK RR, sounds good... Your broadside is directed to me, so you RF lobes would be radiated in my direction (Im guessing you follow what Im saying so far, but this is as much for the readers too...). Since the dipole has greater emissions to the side, then we must assume sensitivity to reception would be similar... greater sensitivity from the side as well. Reception is not as "critical" as transmission, but understanding a horizontal antenna gives better insight.

    On my end, I am running a vertical... so my RF has a different polarity. That doesnt always make any difference, guys with dipoles have been talking to guys with verticals for as long as ham radio has been around! However, if the distance or conditions are not "ideal", then the offending polarity *may* play a role in our inability to communicate.

    Lastly, there is the take off angle, or the angle of which the RF "takes off" of the antenna... I could write a book on the subject and still not cover it, so I wont attempt to do it here... be it said though, the take off angle of an antenna will determine (in part) the effective range of your transmission.

    On reception, the antenna doesnt really need to do much more than be in the zone where the RF is coming in. It doesnt necessarily need to be oriented any particular way or be any specific length (assuming were not talking about any type of YAGI design), but the rule of thumb will always be the same, the more wire in the air, the more RF it can receive. Think of it as a tarp collecting rain water.

    Anywho, we SHOULD be able to communicate, if all the variables are working in our favor. We both know our antennas and equipment are working perfectly, so the only thing left would be propagation and weather. The way to determine this is to be persistent and continue to attempt making contact as we have been.

    In closing, Ill speak on the dipole antenna... Regardless of the design, *any horizontal antenna that has a single radiator and a single radial* is by definition a dipole... same rules apply for a Carolina windom, off center dipole, G5RV, etc.. they are all dipoles and will basically have the same rules..

    Dipoles: The ideal elevation for a dipole is the same as the distance from tip to tip. A 40m dipole will be 66 feet long, thus should be 66 feet above ground. A 20m dipole will be about 16 feel long, and thus need to be 16 feet above ground. When we bring the dipole down to a distance less than ideal, the take off angle rises... The lower you go, the more it rises. This principle is how we can take a simple dipole and make it work NVIS (Near Vertical Incidence Skywave). NVIS is for very short/close in communications.

    My 40m dipole CANNOT be of the recommended elevation, it is mostly about 8 feet above ground (I know, pathetic, but its the best I can do!) so you can just guess how vertical the take off is! It wouldnt surprise me if it were modeled to be straight up into the sky!!

    This is one reason, for me and my location, I prefer the vertical antenna, I get a lot better performance out of it just sitting on the ground, than I can with the best and most expensive dipole... Id never be able to get it in the air far enough for it to operate properly.

    Thats all for now...
    EB


    RR: The short of it is: we will try some more! HA HA!
    "Takes .357 to the field... every time..."
    "AR - America's Rifle"
    "Bushido, an honourable way of life"

  2. #12
    I'll most likely shit myself



    bacpacker's Avatar
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    EB, do you think the vertical vs horizontal could be affecting comms at the distance? One of the guys that was in my emcomm group was big into hf and he complined all the time about verticals. I dont have any experience with them to speak of.

    When my antenna goes in it will be running pretty much n-s. Not quite 180 degrees, but close. The way my property runs, one end is gonna be10-15' off the ground. Feed line will be around 35', the opposite end probably 20-30'.

  3. #13
    plenty of extra room "down his pants"
    ElevenBravo's Avatar
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    Quote Originally Posted by bacpacker View Post
    EB, do you think the vertical vs horizontal could be affecting comms at the distance?
    I think it very well could be a player.. I am self taught electronics & ham, so someone with more formal education in the field could probably give a more definitive answer.

    For example: I used to have an Icom 706 Classic, which had 2m on it... not only that, but it had 2m SSB mode! I hooked it up to my vertical ground plane (144mhz of course...) and could not communicate with my buddy in Floyd county.. He was running a 2m dipole. When we got on the phone, he advised we needed to have the same polarization.. He could not hear me, and vice versa. The next day I made (and still have!) a 2m dipole out of some scrap copper pipe... I built it a little bigger than the formula called for, and using a VHF SWR meter, started trimming a little off the ends until the SWR went flat... I was resonant! That night, I talked to him 2m SSB clear as a bell!

    As I said, verticals talk to dipoles and vice versa every day... HOW the opposing polarities do and dont play well is beyond my scope of understanding.

    EB

    PS
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    "Takes .357 to the field... every time..."
    "AR - America's Rifle"
    "Bushido, an honourable way of life"

  4. #14
    I'll most likely shit myself



    bacpacker's Avatar
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    I knew the vert vs horz was an issue on 2m. Wasnt sure about hf. I think you can probably still talk, just that contacts are not as solid. I'll see if i can talk toa buddy or two and get some input on it.

    BTW the 706 is the radio I have.

  5. #15
    plenty of extra room "down his pants"
    ElevenBravo's Avatar
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    Thats what, to the best of my memory, I understood too... that VHF was more of an issue, so I can only speculate on HF...

    Let us know what your EM buddy thinks...
    EB
    "Takes .357 to the field... every time..."
    "AR - America's Rifle"
    "Bushido, an honourable way of life"

  6. #16
    plenty of extra room "down his pants"
    ElevenBravo's Avatar
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    I wish I had some trees to run my dipole up proper with... The ones I have (legal) access to are not of top choice, one end is in a tree limb (guy wire is anyway..), the other end at my roof's peak, which is of course not very high for a dipole.

    EB
    "Takes .357 to the field... every time..."
    "AR - America's Rifle"
    "Bushido, an honourable way of life"

  7. #17
    Bacon saver

    Brownwater Riverrat 13's Avatar
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    Damn I guess I missed the educational portion of our programming guide tonight. You guys are just way to smart for me. All I can give you for numbers is that mine is approx. 30' at the feed point and 10' on the ends at an inverted "V". I couldn't put it up horizontal. Try try again, can't wait till you get your windom up Bacpacker. Still, we must continue... we'll make it work. Great intell guys!
    Be safe.............the night is your friend.

  8. #18
    I'll most likely shit myself



    bacpacker's Avatar
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    BW, an inverted V like you have works just fine. They dont have to be a flst top. Mine is gonna be an inverted V as well. Just running the Windom as opposed to a pure dipole. My feed point is at the 1/3-2/3 point instead of midway.

  9. #19
    plenty of extra room "down his pants"
    ElevenBravo's Avatar
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    OCF Window I am guessing... I ran one a while back, it was a good tuner and worked good for me!

    EB
    "Takes .357 to the field... every time..."
    "AR - America's Rifle"
    "Bushido, an honourable way of life"

  10. #20
    I'll most likely shit myself



    bacpacker's Avatar
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    Yeah Carolina Windom. A buddy of mine had one up for a while. He had good luck with it. His was flatter on top than mine will be, but only up about 25'. Also he lives on a decent hill top. He used his working digital a lot.

    I talked to a guy I work with today who does some HF, mostly on 17m. He agreed the vert vs horz could cause some issues, especially at closer ranges. He has a antenna book from the ARRL and said he would see what it has to say.

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