I can never get a decent SWR with a using a small coupling loop, until I used a ferrite toroidal (type 43 mix) couple to the main loop, l believe also an gamma match gives the best results. I really like your design especially the remote capacitor.
ı have made three dıffrerent sıze of mag loops good for 20mt. and 40 mt.dıameters about 1 and 1.6 mt.never suffered from swr problems.thank you.de Ta3iid..
Great video Helge! Q: Regarding the feed-loop, is the junctionbox (coax center connected to shield) half way around the loop? Another comment, the "magic black spot" could possibly be avoided if you have rounded the corners! If you study the area, you'll see the start/stop of the spark is from the corner!
Yes, this joint connects the center conductor to the shield. Yes, you may be right. With rounded corners, perhaps this could have been avoided. Good suggestion.
I enjoyed watching this outdoor loop antenna on the field. I am very interested if you can produce a video on the construction of the tuning capacitor and the remote control circuit. As always thanks for producing very interesting videos....VA7VB
Great design! The capacitor looks specially simple and easy to build from scavenged parts. Thanks for sharing always useful and entretaining content! 73 de PY2ALV.
A very interesting and simple design! Can the capacitor be enclosed in a box so it can be used in damp weather? Can it be sealed in a Tupperware box with some silica gel desiccant to absorb the moisture? Thank you for showing us this design! 73 JS2OLO Japan
Great project! Please can you describe the dimensions of the capacitor plates and Teflon dielectric? It looks like a thin sheet. Where is this Teflon available?
Would a suitably wide copper tape taped onto a long strip of plastic wrap work well I wonder? Cant imagine a loop like that weighing much over 200 grams when sized to 18 meters length.
Hej Helge, mycket intressant video! Jag antar att du har mätt bandbredden med den här fina Network Analyser. Vilken bandbred får du på 80m? Uppmätta bandbredden är ger ju ett mått på effektiviteten. Jag undrar också hur närheten av husvagnen påverkar antennen. Har du några jämförelse siffror på när du har antenn på gräsmattan kontra husbilen? 73 SA5NTK
Thank you, The bandwidth is at least 10 kHz without the SWR becoming too large. That we say 5 kHz to each side. It is therefore no problem to fit a SSB signal. I have not noticed if the motorhome disturbs the antenna. But it is possible. A new video will come later when I have gained more experience with it.
Thanks, for this Shape idea for a portable magnetic loop antenna! Q: coax type for the 80m and 40 m portable loop? Only use the shield off coax? Same variable air capacitor? Thx, 73 Theo Pa0hty
Thanks for the question. I only use the shield on the coax cable. The coax cable I used was an unmarked type with a copper shield and a diameter of approx. 10mm. Uses the same capacitor at 40 and 80 meters. 40 meters with small coax. I use the 19 meter coax at 160 meters. Then I have a fixed capacitor in parallel with the variable.
