Wednesday, December 26, 2018

Striving for a better bandwidth

Original shape of coupling loop 
My last couple of posts have been dealing with extending the bandwidth of my MFJ 1788 loop antenna. With the loop the lower the SWR the more bandwidth I  have before I have to retune the loop. Up to this point I have tried moving the antenna ALL over my balcony and the best SWR at that point was at best 1.6 with the loop in the horizontal position. I then gave the loop a go in the vertical position something I had never done before. I was surprised that the loop had a better SWR, I was able to get it down to 1.4 SWR. One last suggestion given to me was to adjust the internal 10 gauge coupling loop. Today I took the section of the cover off that exposed this coupling loop and moulded the loop from it's "0" shape to more like an egg shape. with doing this I was able to lower the SWR do 1.2 to 1.3 depending on the band I was on.
New and improved shape


  1. Hello Mike, Happy New Year, for you and Julie.
    I once made a loop from a 7 yard long cable. I experimented with the length of the feeding loop to get a good SWR. I suggest to extent the black wire of the coupling loop with a an inch or a few inches. Good luck. 73, Bert

    1. Good morning Bert and very nice to hear from you, excellent idea and I can pickup the 10 gauge wire from work and give it a go on the next long weekend when I have the time.

  2. Hi MIke,
    I'm glad to hear that compressing the secondary loop has helped.
    Enjoy that new Icom. A waterfall and knobs. The best of both worlds.
    73 de Paul VA3ZC

    1. Good afternoon Paul and very nice to hear from you again, yes the "egg" shape does not look very pretty but it was able to get the SWR just a bit lower. Thanks for the advice and have a great weekend.
      Mike VE3WDM