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MFJ-1786 Magnetic Loop

Discussion in 'Amateur Radio Antennas' started by Riverman71, Nov 26, 2018.

  1. Riverman71

    Riverman71 Part-time Member

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    IMG_0422.JPG


    First off, all the reports of poor quality control on these hold true. The antenna rattled upon removal from box. I removed the twenty screws holding the plastic cover together and found two steel nuts bouncing around loose inside. I quickly determined these were two of the four whose mission is hold the large capacitor in place. Luckily, it was firmly secured by the remaining two so I simply replaced the loose ones and cinched them down right. Upon closer inspection, everything else looked good. I then screwed the cover back together and unpacked the control unit. A good shake revealed nothing loose inside so I decided to leave it be.

    Options are limited when one wants no tall masts in his/her backyard or wires draped between the house and trees. As I have mentioned before, I loved my Alexloop. But with manual tuning they are not the best choice for hot summers and cold winters. o_O The 1786 has remote tuning. And handles 150 watts.



    Also, I'll now be able to add a CB to my station without the need of an additional antenna as this one covers 10-30 meters.

    Am waiting on the tripod I ordered from Solid Signal. It should be here tomorrow.

    More to come . . . .
     
    #1 Riverman71, Nov 26, 2018
    Last edited: Nov 26, 2018
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  2. jon666

    jon666 Sr. Member

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    i have one. does a pretty good job. i talked skip 5 feet off the ground.
     
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  3. Riverman71

    Riverman71 Part-time Member

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    1786.JPG

    All set up! Each leg of the tripod has two 8" steel rods driven through the holes used to attach it to a roof. Antenna is connected to 75' of RG8X.

    Station.JPG

    It's great to be in the house rather than the garage! Now for the important stuff . . .

    Got everything hooked up and turned on. With butterflies in my stomach I went through the testing procedure for the controller. Worked perfectly. I then tuned my radio to 14.249 MHz. Using the controller I was able to obtain a flat SWR. No reflected power!
    Switched radio to 14.250 and some fella from Ontario Canada was booming in. When the time was right I tried to contact him. He could faintly hear me. I then realized I still had my power set to 5 watts! Dialed it up to 50 and we had a nice QSO. Butterflies are all gone!

    Discovered what I'd hope to find. When tuned to 14.250, I am able to listen to the entire phone section of the band (14.150 - 14.350.) Also, the acceptable SWR range (Less than 2.0) appears to be about 30 MHz. wide (14.235 - 14.265) on 20 meters. This is much wider than I'd anticipated. Don't know if this will vary with other bands.

    I am tickled to death. For Christmas am getting a larger wooden table that matches our office furniture. And perhaps add a CB. In the meantime I need to go find something to place under the 1786 controller to tilt it upwards a little for a better viewing angle. Then I'll be set.

    Well, the solar cycle conditions may be poor but activity on 20 is crazy right now. Time to play!

    Take Care,
    Jim
     
    #3 Riverman71, Nov 28, 2018
    Last edited: Nov 28, 2018
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  4. StrangeBrew

    StrangeBrew Sr. Member

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    If I'm not mistaken these are supposed to have two nulls off the edges of the loop, would those nulls be enough to use for eliminating unwanted signals? I'd be interested in your thoughts after using it.


    PS: Cover that thing with evergreen branches and you could mount it on your roof, if anyone asks it's a wreath not an antenna.(y)
     
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  5. Riverman71

    Riverman71 Part-time Member

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    I believe that's right. I know a lot of people use a rotor with these when mounted vertically. Horizontally, they are pretty much omni-directional according to the manual. I haven't rotated mine any yet. As is, (pretty much East/West) the noise level is very low and I hear people from all directions. When mowing season comes in the spring, I do plan on mounting it on a mast horizontally (to catch less wind) to get it out of the yard.

    It may go south tomorrow, but I am elated right now. This antenna isn't for everyone, but it fits my bill perfectly. And the re-tuning isn't that big a deal. Kinda fun, actually. LNR Precision makes a remotely tuned loop but theirs is limited to 15 watts. I've always said I enjoy QRP (and I do) but being able to use more power might be fun. Okay, Gary, (wherever you are) you can say I told you so! (y):D
     
    #5 Riverman71, Nov 28, 2018
    Last edited: Nov 28, 2018
  6. Riverman71

    Riverman71 Part-time Member

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    On a side note, after routing the coax into my house I had to install a new PL-259. Trimmed as needed, put my new crimp tool to use, soldered the tip and was done. A lot of worry for nothing. :)
     
  7. Road Squawker

    Road Squawker Sr. Member

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    Choke, Choke,... Gasp, Gasp,.......I just checked the DX Eng site and saw the price:eek::eek::eek::eek:
     
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  8. StrangeBrew

    StrangeBrew Sr. Member

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    Yeah, not cheap. But they can solve a lot of problems if you're limited on what you can put up.
     
  9. Riverman71

    Riverman71 Part-time Member

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    Yep. A hard pill to swallow for sure.
    Especially given the commonly reported quality control issues. o_O I wish all MFJ products had as few problems as their antenna analyzers seem to have.
     
  10. Riverman71

    Riverman71 Part-time Member

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    That's me in a nutshell, StrangeBrew. Wish it did 40 meters but when the solar cycle begins anew, 10,12, 15, 17 and 20 will be plenty. Oh, and 11. ;)
     
  11. 338_MtRushmore

    338_MtRushmore Well-Known Member

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    Why not the mfj-1788 instead? Just curious
     
  12. Riverman71

    Riverman71 Part-time Member

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    The 1788 covers 15-40 and the 1786 does 10-30. I'd like to have 40 meters but wanted 10 meters more. Also, these type of antennas are much more efficient at 10 than they are at 40. Can't have it all doggone it.
     
  13. 338_MtRushmore

    338_MtRushmore Well-Known Member

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    I knew I was missing something. I have glanced at those before and thought the 88 was 10-40. That would still work for me if I left my a99 up. I might have to look into that some more. The quiet RX would be a major plus for me.
     
  14. Riverman71

    Riverman71 Part-time Member

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    I don't have an A99 so need the 1786 for 11 meters. Yep, 1788 would work for you. (y)
     
  15. Riverman71

    Riverman71 Part-time Member

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    Well, the fly in the ointment finally showed up. And let me tell you, the fall from Cloud 9 is a long one.

    Had only been using the SWR meter on the controller when I decided to check the one on the radio. With the controller's meter showing no reflected power, the radio's meter shows a SWR of 2.0. and my antenna analyzer reads 2.2. When I change frequency (without re-tuning) enough to get a SWR of 1.3 on the controller's meter, the radio shows nearly 3.0 and the analyzer confirms it.

    Other than a problem with the meter in the controller, any ideas?

    Thanks!
     

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