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Thursday, 28 January 2010

G4CQM Yagi Designs

I see from Southgate ARC news that Derek G4CQM is looking to publicise his antenna designs. He has done an update to his website with several new antenna designs. The designs are fairly simple to construct and all the details are available for free on the website. Lionel VE7BQH has provided performance analysis tables that show how well the antennas should work.

The only issue I have with Derek’s designs are that he insists on using Netlon clips to mount the elements. Netlon clips are designed to hold garden netting for climbing plants or shading. The problem is that the clips are held in place by a single bolt, which means that over time the elements move out of line and eventually spin like helicopter blades in the wind. Still as radio amateurs we tend to adapt other peoples designs rather than follow them to the letter so I don’t see it as too much of a problem, unless of course you buy one of Derek’s kits.

Edit: I was wrong about the Netlon clips. See Derek’s comment bellow


  1. Steve you are wrong! There are two holes in the Netlon clips, one in the spine of the clip and one under the jaw that holds the element. By using the two holes the clip DOES NOT SPIN. Derek/Richard provide TWO self tappers with their yagi kits to stop rotation!


  2. Hello Steve,

    I must correct you, Netlon clips are secured with TWO screws and not one as you have wrongly stated! I have been using Netlons since 1994 and purchased a huge quantity direct from Netlon Sentinel.

    They have proven to be very popular and effective. Users include experts such as Christopher Bartram GW4DGU and Ian White GM3SEK.

    Regards, Derek G4CQM

  3. Cheers and appologies to Derek and Robert thanks for putting me right on that one. I can only imagine that the clips I bought(years ago)when I first saw them used were either a slightly different design or from another manufacturer. They certainly looked the same but came with a woodscrew that I replaced with a stainless steel bolt.

    Regards Steve GW7AAV