End Fed Half Wave Transformers.......Are they as good as we think? #hamradio #hamr

Colin, this is an extremely impressive example of digging deep and organising your research for the viewer. Efficiency is an interesting concept. One question (which you addressed via your colour coding) is how to benchmark this. It is interesting to note that if we compare your figures to a ground-mounted quarter-wave vertical over typical AVERAGE ground, with 32 quarter-wave ground radials (so that would be 160m worth on 14MHz or 320m worth on 7 MHz), the efficiency of the quarter-wave would be somewhere in the order of 72% (-1.7dB). Most of your designs (with a couple of exceptions) beat or at worst basically equal this. The alternative ferrite (same mass but smaller and chunkier than the 240-43) looks a real winner. The efficiency figures you have with that are excellent. Even a 2:1 feed-point SWR and decent coax will add little to the small loss of that toroid. One other thing - your issues with the SWR on the inverted-L, I can only presume your angle of the L is less then 90 degrees (sloping down?), this may well play its part, but a slightly raised SWR is a good price to pay for an efficient transformer. Well done Colin, this is the best analysis of EFHW design I have seen on YT (including the Steve Ellington ones). Keep up the great work. 73.

Hi, nice to see someone else actually measuring loss! When you stack 2 FT240-43 and do a close wound 14/2 you will find that to be very efficient also. I've spent hundreds on ferrite and wound hundreds of different transformers looking for ones that are efficient across all of 80 to 10 meters, and every one of them was 43 mix. You can find some that are 52 or 61 mix that are quite efficient, but not across that many bands. Also cap values different than 100pf will measure lower loss across the usable bands in some cases.

Awesome work and great presentation. Thank you!

Great presentation very helpful 😊

I found this to be an excellent video - Your honesty in your descriptions is welcome. Well done. Thank you

Wow, this is wonderful work! Thank you so much for doing all these tests with quantifiable results.

Dedication for sure. Well done and be watching for your experiments on the bigger version.

I like this guy's like "my talk, my tea." What a boss

This is fantastic work!!! You have saved me a lot of time and money!!! I cannot express how excited I am to see this work, and your presentation is very clear and well documented!!!

Thanks, as a new ham I found this quite educational. The whole subject of antenna design is quite fascinating. I appreciate your hard work in making this video.

I followed Steve Ellington's advice and stacked 3 FT240-43 cores, Colin. Distressed beyond belief that this might not be the most efficient way of doing it! I've been down all sorts of rabbit holes, some of the folks your chat with online and on air told me "no mate it's not the cores heating up, it's the wire!", so I have replaced the winding on some of my transformers with teflon coated silver wire (luckily picked some up cheap at a hamfest). Maybe that makes some difference at high power, don't know. Maybe the EFHW while great for QRP and 100W is not the most efficient at 400W (Aus limit) and even less so at 1000W. You have inspired me to start measuring myself... You do high quality work, my transformers never look as good as yours... 73, Tim, VK4QP

Outstanding work. This changes the way I will be winding my torrids. I look forward to more testing.

Thanks Colin, you put a lot of effort into this.👍🏻

Great video, Colin, and interesting results. There's so much folklore and witchcraft surrounding the EFHW transformers, it's nice to see some actual science being done. 👍 I put up a temporary EFHW for 40m at home about a year and a half ago which uses exactly the same core you ended up with, after reading Owen Duffy's page(s!). It's still up and working very well indeed.

Wow, best EFHW transformer myth busting video seen so far and I've seen a lot!!. Thanks for posting and also providing the matrix. 73's from VK3

Really great information! I’ve been wondering about which way to make it better and this definitely has me thinking differently!

Great work colin and I’m lookin forward to trying mine out!

Thanks Colin for your hard work in doing these tests and producing a great piece of research for us to see. 73's Andy M6APJ.

Thanks for the doc and info.

Colin, I salute you for making this video! - The amount of work you must have put in to make this video, to get the very good and presentable results you did, must have been phenomenal. This sort of research is of benefit to all thinking amateurs who are thinking of making and using an end fed half wave. Regards to you Colin, David (M0XQZ).