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Thread: End fed HF antenna - advice please

  1. #1

    Default End fed HF antenna - advice please

    Greetings everyone. My first post here so please be nice

    Iím returning to amateur radio after a forty year break and making my first foray into HF.

    My first task is to erect an antenna. My wife is very proud of her garden (and rightly so) and doesnít want it spoilt with an unsightly antenna farm, so my initial solution will be an end fed random wire. I donít want to bring the radiating element in to the shack which will be on the first floor (second floor if youíre in the US!)) so Iím thinking of using a 9:1 unun with a short coax feed.

    My question is about the earth/counterpoise requirements. I know there are as many solutions as there are radio operators, but as I understand it these are some of my options:

    1) No connection to unun ground (except coax feeder screen)
    2) Copper wire to unun ground running down the wall and connecting to a ground stake. The wire will be 6 metres long
    3) Counterpoise wire connected to unun ground (i.e. not earthed)
    4) As 2 or 3 above but with MFJ-931 artificial ground

    Iím planning to use no more than 100 watts and my initial bands of interest are 40m and 80m.

    Before I begin, any advice on what might work best please?

  2. #2
    Super Moderator 5B4AJB's Avatar
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    Long wires are notorious for noise - in and out. Have a go at making a magnetic loop which you can use in the shack. The only "expensive" part is the variable capacitor.
    For 100W on 20m - 10m, with a 1.5m diameter loop, I recommend something about 5-6" in size.

    Long wires are pretty good for receiving, but transmitting is another thing...

  3. #3

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    Thanks, I'll have a look at those but I think it would be quite large on 40 and 80 metres ...

    Mike

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    Super Moderator 5B4AJB's Avatar
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    80m might be tricky inside, but a 1.5m diameter works well on 20, it will tune up on 40 but the efficiency is a fraction of a percent, it does work but is rather deaf on 40m.

    There are hams with top band loops made from wire which are quite invisible however...

  5. #5

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    I am currently using an ULTIMAX 100 that is working from 80m to 6m. It is 24 F in length -- so it is pretty close to your 6m (more like 8m) and it does not have any grounding requirements.

    It will probably need to have an antenna tuner -- I have an auto one connected to an IC-7000 that works great. I have noticed that the antenna tuner needed longer feed line -- and I have about 15m of feed line -- and 1/2 of that is coiled in the shack. I have mine connected between a gazebo and the house -- something that the wife approved. It slants up to the house eve, so it sounds like it could be similar to your situation -- I have it running into a second floor (US second floor) window.

    In the US, the ULTIMAX 100 costs about $80, and is also available on ebay.

    Good luck with whatever you end up with. I was absent from the hobby for about 50 years and got back into it and did so not knowing if I would really like it or if it was just one of those things. So far, I am enjoying it a lot and recommend getting in touch with a local club.

    Cheers & 73 K4CQO

  6. #6

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    Thanks, I'll have a look at the Ultimax.

    I understand that it's best to feed the wire at the far end so the unun can be grounded by a short lead.

    If I do that the feed cable is going to be around 60 feet long. Is that going to work?

    Mike

  7. #7
    M0WAO's Avatar
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    Quote Originally Posted by K4CQO View Post
    I am currently using an ULTIMAX 100 that is working from 80m to 6m. It is 24 F in length -- so it is pretty close to your 6m (more like 8m) and it does not have any grounding requirements.

    Cheers & 73 K4CQO
    Hmmm https://en.wikipedia.org/wiki/Ultimax_100


    http://ultimax-antennas.com/store/p1/ULTIMAX_100.html
    73 de Biton - m0wao - echolink 633710
    Icom IC-7000
    dx-code

  8. #8

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    Everything has a price, and usually better costs more. I have an Ultimax reeled up in the shack for a last resort antenna because it receives much but transmits little, I bought a Chameleon Antenna CHA-HYBRID several years ago and haven't looked back. They just work. Mine has a 1/8" stainless cable 66 feet long that I made to allow the Hybrid to be suspended above the shack. I have worked every band and while it is still a compromise antenna, it's the best bang for the buck out there. I would have saved a lot of money had I found these first. I also have a Hybrid mini in my go kit that I take on vacation and find it performs equally as well. I would have to write a book to explain all of the antennas I have tried and the money I have parted with both buying and building antennas over the years. Yes, you will get on the air with an Ultimax or any other such antenna, and no, even a chameleon won't match a beam up one wavelength in the air,

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