Category: Antennas

  • Vertical antenna for 15m

    Our small group of CW ops and learners meets on a weeknight on air but have found it hard to find a band that works for all of our group. The logical choice of 80 or 40 is considered out of the question for the apartment dwellers. So we’ve looked at using the upper HF…

  • Magnetic Loop – step by step

    Well, the replacement stepper controller chips arrived early this morning. Didn’t take too long to replace them and connect everything up for a test. The good news is that after a slight adjustment of VR2 the stepper appeared to be controlled by the rotary encoder. It made the right noises. Try as I may, I…

  • Magnetic loop progress

    Finally found some time to re-orientate the two transformers. I decided to remove the eight bypass 10nF capacitors to give my soldering iron more wriggle room to remove the transformers. The solder on the transformer pads needed some encouragement – in the form of more molten solder – to loosen up. This allowed me to…

  • Magnetic loop fault finding breakthrough

    Maybe my mistake has been not to refer more directly to the actual code. Over the last 24 hours I have been steadily working through the last two years of email conversations. Loftur keeps the group informed of each new version of the firmware and the newly added features. Sometimes he jumps the gun, but…

  • Magnetic loop controller – home stretch

    After a long break I have finally got back to completing the Magnetic Loop Controller designed by Loftur Jonasson that I started almost two years ago now. I am using his original PCB version from June 2014 which indicates how long I have been intending to build this device! I noticed a small SWR board…

  • Milk crate tower

    POSTED ONOCTOBER 26, 2017 Milk crate tower Wacky idea #257 of the day Since they were invented – apparently by an Australian engineer (see below) – milk crates have been used in many other ways besides holding milk containers. Everything from furniture to milk crate versions of the Loch Ness monster. Six interlocking milk crates…

  • Falling squid poles

    Or how Stephen just realised the error of his thinking for the last few years…. again. Recently I’ve been thinking more about the perennial problem of using squid poles as antenna supports – the fact they all too readily collapse into themselves. This is probably more of an issue with permanently set up poles, but…

  • Back in the loop

    My main project for at least the last 12 months has been building a solid magnetic loop antenna and its companion automatic loop controller. I’ve been roughly tracking its progress at my magnetic loop antenna project page on this blog. As usual, life has got in the way, but I want to get back on track and…

  • Smartlock

    The Smartlock is an accessory for my SGC SG-239 HF Smartuner, and other ATUs they make. It can be bought ready made or built. There are indicator LEDs that signal status (TND, l ‘Z’, 2:1, PHZ, FWD, Auto & Man) on the lower section of the PCB of the SG-239 but they are only visible…

  • Success!

    Great moment this afternoon when the Automatic Loop Controller fired up as it should. Happy days. When I first fired it up, after loading up the Arduino program, all I could see was a dull green glow on the screen. It wasn’t until I remembered a comment from another builder about adjusting the potentiometer on…

  • Antenna tuning by stealth

    One of the most important documents for anyone who wants to know what makes a magnetic loop tick is Leigh Turner VK5KLT’s “An Overview of the Underestimated Magnetic Loop HF Antenna” which can be found on his club website. Midway through building my version of Loftur Jónasson – TF3LJ / VE2LJX‘s Automatic Loop Controller, I came across…

  • Buddipole vertical for 80m

    I spent the pleasant sunny part of the final day of autumn testing a vertical antenna for 80 metres using Buddipole parts for home. The back garden space here is barely 4 metres by 4 metres and for the moment the chimney is out of reach. While I have dreams of a magnetic loop for…