Having shown you the vacuum capacitor I use to tune my magnetic loop antenna I thought I would show you the capacitor connected to the loop and the match on the antenna analyser.
Congratulations, you have hit on the single most important development in getting a loop antenna to work really well - feed it with a toroid! About 35 years back I put a lot of effort into trying to build an effective DF loop for 27mHz. I tried every design I could find that was supposed to work and they were all average to poor performers. the reason being that the impedance match bad and there was feedline radiation / pick up that caused inconsistent results. Another Ham suggested that a toriod feed might be worth a try, well I tried a F25 (?) grade ferrite. think I had 4 or 5 turns on the feed side, the secondary being effectively half a turn... Well that sure fixed it up, more signal, perfect balance and very deep nulls, the problem signal were located in a very short time. I still have it in the cupboard, VK3KCX
I made a 5.1 diameter Mag Loop for 40M and the SWR was at a 4.1:1. That was with a thin aluminum 1/2 metal as the smaller loop. The 5.1 loop was made with 1/2 copper tubing. I made a smaller octagon with the same 1/2 copper and the swr was 3.6:1. The signal strengths that I got was astonishing, in comparison to my OCF wire dipole and my 75M hamstick dipole. I really want to try these the next time my Cub Scout unit goes camping. I want to see how it all sounds away from the QRM in my town. Thanks for the video! Andre, N2JDH
Hi great Idea. I made a magnetic loop dual band aerial for QRP operation. Fine and course tuning capacitors. Used car brake pìpe and a selfie blogging lighting tripod. Works great and lightweight for portable use. I will experiment with your idea. Cheers from old George in the UK 👍🤠🇬🇧
Do you think its better to use a ferrite core for coupling to the outer loop like you did or it doesnt matter to use a simple one turn small loop to couple it with the outerloop? Thanks
VK6CS idk, the coupling loop made 1/5 size attached directly center opposite of the capacitor usually works 99.9999% of the time the first try. The side opposite of the cap is basically close to 0 volts in the center and can actially be grounded and mounted to a pole. The cap side will degrade the swr severely if it gets near anything conductive. I usually just let the inner loop touch the outter loop as it has no effect and insulation is unecessary (as long as its completely centered). If the coupling loop is too large just squish the end near the big loop closer and it will lower the swr. Usually 1/5 the circumference of the big loop is the magic bullet. It would be awesome to compare all three methods and see which has lower losses/more gain.
Hi Richard. Yes indeed it would. The toroid is more convenient for portable loops made from coax, they can be folded up with the toroid permanently in place that's why I was most interested in that method. Maybe I'll give the other methods a go and do a comparison as you suggested when this amplifier project is all done and dusted.
Hello, sir! I'm Daniel, YO8UFO. I want to know, if you can tell me, what is happening if you add or substract a few turns on the toroid. How is this changing the behavior of the antenna? Can I use just one turn, or 10 or 50 turns ? Thank you !
I do all of my films on a potato, (galaxy S2), so I don't have a problem with this one. I got the information I wanted by hitting the space-bar, using full-stop and comma keys to find a clear frame; Alt+PrtScn , then paste to MS paint and expand as needed.
Good sir! May i ask what type of toroid, the gauge of magnet wire, and the amount of turns you enlisted in the creation of your coupling transformer? Good Day and 73's !
You certainly may good Sir. The ferrite core is a Jaycar LO-1238, the wire is Jaycar WW-4024 and there was about 12 turns. 12 turns should at least get you in the ball park. 73.
The coax is connected directly across the coil. It acts as an RF transformer where the coil is the primary winding and the loop is the secondary winding.
I don't know why you worry about security - The Mossad already knows where you live - 619 Murray Street. Assuming you're still with us of course, and have not been whacked, we look forward to watching some QSO videos. By the way, I did particularly like your capacitance matching box - very sweet :-) Thanks Steve - Putting the amateur into radio - and the FUN.
Thank you for sharing on your design efforts. May I ask also about your use of a wound core as a driving or “inner” loop as opposed to the “traditional” 1/5th simple inner circle. I am currently working on a 2 meter diameter loop constructed of 4” copper ribbon and have been struggling with decisions regarding the inductive inner loop as well as the “come together” of it’s top end for connection to the capacitor
I haven't tried the 1/5th coupling loop design so I can't tell you from personal experience. I can tell you the Ferrite core method seems to work well, and that you need to keep all connections as low resistance as possible. Maybe you could try a gamma or delta match to your copper ribbon. There's also an 'Army Loop' type of match using capacitors: i.pinimg.com/originals/71/27/a8/7127a8aded1af4dba205c1a2ea89d0ee.jpg
I saw the feedpoint toroid was out of focus initially but didn't worry too much about it as it appears in focus and shows the detail clearly further on in the video. 73.
hai hai there here 9m2du son of 9m2gv from malaysia .it has been loog time not on the and has been long2 time .we do have a contack last time . but couldnt remember. we friend with VK6 PZ of which long2 time have not contack ever since dad silent key. so how every thing out there .it seem the band condition is bad ha haha ha ah .. wi try later on bye 73 from 9M2DU this vedio good keep it up ..chereeeoooo
Could you zoom in some more? I like not being able to see more than a 3 inch field of view. Maybe next time you could tape a toilette paper tube on the end of the lens so we can only see a small circle of what you are showing us.
@@vk6cs456Per Google translate: After seeing this video I ended up dizzy with the desire to vomit because of the worst of the video I would perish I was at sea mounted on a boat.
My head hurts, don't waste your time watching. This guy has no idea how to make a video. He walks and moves the camera so much it will make your head spin the first 10 sec. PLEEEZE redo or take this one down ASAP. It's awful . Can't even watch 5 seconds of this
Yes, the video quality is lacking...but he posted something that was educational. When you have something for us to learn from...post it and see how well you can do...until then, be constructive with your comments.
