Low Loss EFHW Ham radio HF antenna antenna tests. Do capacitors matter ? DIY and save your money !
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- Опубликовано: 31 июл 2024
- Second video in my EFHW antenna build series. In this video we mount up the transformer from my first EFHW video and test it in a few configurations. Spoiler alert this is the most efficient End fed antenna I have ever built or used in my 25 plus years as a ham. You can build it yourself as well for a fraction of what commercial vendors charge for a less efficient product. Thanks to the following channels for their content and information.
@MM0OPXAmateurRadio
@evil_lair_electronics
#Survivalcomms 
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This is the best presentation I’ve seen .Not only theoretical but also practical demo’s with real life results. Thanks Brett. 73 VK2SS
Thank you ! and Thanks for watching !
Good looking work and data. No nonsense detailed video . Enjoyed this video very much. Don K7DT
Thank you very much and Thanks for watching !
Colin puts in the miles, for all of us, we are fortunate to have him.
Yes he does ! I am thankful for the leg work he put into his research. Thanks for watching !
Exactly how I have done mine; wound including using the TDK cap, except I didn't even use any acrylic boards...just hung mine on an insulator out in the open.. it's a passive device so no worry. Feed mine with about 75' of LMR 400, and a short RG8X jumper. It's really light low loss coax, especially on the HF bands, so you can haul it up into the air easy. more lossy RG8 weighs 2X as much, and RG 58 gets quite lossy up toward 10M. I try to keep my losses to around 1db and at 90% efficiency of the 2643251002 core wound as shown, and the TDK cap you can possibly do that. No guarantees but you can get close... If your running semi-qrp, only 20 watts O/P, as I do (Xeigu G90) every watt counts.
Very cool ! Thanks for watching !
Thanks for doing good work! 👍
Thanks for your work and thanks for watching !
Fantastic work as always 👍
Thank you very much ! Thanks for watching !
Really well done. Trying to get my efhw to perform better on 80 meters. Keep up great work. 🎉
Thank you ! Thanks for watching !
As the efficiency of the autotransformers go up, Brett's is close to or may actually exceed 90% the true chracteristics of the antenna come into focus.. It's a real challenge juggling the resonant points on your preferred bands... 80 will likely be down around 3550, that's where mine sits... but I don't use 80 much where I live.
@@mortimersnerd801 Very true balancing the band resonant points isn't easy. With a more efficient transformer you really see it more so than with a design that exhibits more loss.
Thank you
You are welcome ! Thanks for watching !
Excellent video. I see you run with the transformer up high. Wii it work in a L configuration with the transformer let's say 12 feet up as my fiberglass pole is too light to handle the weight up high. This transformer is actually quite light and may actually work up high. I have a DX commander pole but want something quicker and less complicated to deploy and am on a quest to build one of these transformers. Thanks for all the information.
Thank you ! The best advice I can give you is to give it a try. The further you can get your feed point from ground the better but one has to work with what they have . Try it out and let me know how it works for you. We all learn from one another's experience. Thanks for watching !
FWIW, I run my EFHW in an L configuration. I have found that trimming the antenna in the configuration you expect to use is the best way to get consistent results. My SWR value deployed as an L versus a sloped wire or hung horizontally are all different. So I have wires cut for each configuration as I use it mostly for portable uses. For my L I have the feedpoint at about 4-5 feet off the ground. With a 30-ish foot telescoping mast and a 40m EFHW that provides about half vertical and half horizontal.
Also fun fact seldom mentioned, in that L configuration the 10m and 15m signals are best at about 30 degrees to either side of the horizontal tail in the direction it points. Setting it up with the tail pointing east for FD(on east coast, NC) I was hitting 15m skimmers in EU better than inside the US. Oooops.
@@ElDiabloLocoPoco Thanks for watching !
Thanks for good information. Excellent. I understand your autotransformer (49:1) is 14 turns. I presume you are quite satisfied with swr over the 80-10 m? Watching Colin's ( MM0OPX ) experience he had to add an extra turn ( 15 ) in order to get better swr results on 40m. Any toughs on that? I suppose an atu would probably deal with any mismatch on lower bands 40m-80m.
You are welcome. I am quite happy with 14 turns. Thanks for watching !
Thank you for this video! ... vy73 from Hamburg/Germany, Dietmar, DL4HAO :)
You are welcome ! Thanks for watching !
Thanks for the detailed, easy to follow explanation! It was nice being able to see the transformer sweeps. Spending a little extra on those TDK caps paid dividends. Was the exercise you did part of an AUXCOM class?
Thank you ! Good eye - the participants were working on their PTB . Thanks for watching !
I enjoyed your video. I’m looking to find the best Toroid for doing QRP. I have an Icom 705 and I want to build the most efficient end-fed half-wave I can. Happy Holidays!!!! KC2KNA
Thank you ! I am glad it helped thanks for watching !
A 43 mix toroid will work.
does that mean someone might want to consider adding a transformer to their CB radio internally? by the antenna jack...
You are much better off just building a simple quarter wave ground plane for a CB radio IMHO. If you desired to use wire you could build a delta loop , rhombic , etc and outperform an EFHW for less real estate. If you are by necessity forced to end feed a half wave at 27mhz you could put the transformer at the RF connector but your radio chassis is going to be a larger part of the antenna than you would want it to be. At low power a few feet of wire tied to the chassis would help. Thanks for watching !
:O )
Thanks for watching !
Thanks for the videos on EFHW :-) just send you an E-Mail with some of my measurements with different Toroids (also MM0OPX variant) vy 73 de DG1JAN
Awesome ! I look forward to seeing it. Thanks for watching !