My choice. Easy to build and starts with 0.01 uH and 0.01pF
73 Chris
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Hallo Matt, I have mine from Funkamateur Shop.
73, Peter - HB9PJT
I can confirm the detailed description by Gary Rondeau (Engineering the EFHW 49: 1 Transformer and Antenna) based on my own measurements.
Nevertheless, I will stick to the classic technique, but use the gear ratio of 1:49.
Incidentally, I have also found that twisting the 2 primary turns with the secondary turn does not result in any lower attenuation. Therefore I suggest a simplification (picture still shows ratio of 1:64).
73 Chris
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Thanks for showing your results Chris.
I have always done the twist method until lately. I have not measured the difference between both methods yet.
Malen
VE6VID
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Chris,
how did you couple the high end to the analyzer?
73 Ludwig
I took a 3,3kOhm 1/4W carbon resistor. Without the unun the analyser shows a flat response.
It gives a attenuation of -3.2k/50 = -64 = -2^6 = -6 * 6db = -36db.
The 1:8 unun should transforms 8 times = 2^3 = 3 * 6db = 18db.
Total gain -36db + 18db = - 18db
Thatâs excactly what my analyzer shows. In my diagramms I have change the -18db / -20db to 0db / 2db.
73 Chris
2 Likes
Good to hear 
73 Chris
1 Like
At the end of my unun measure session I build a very ugly unun with big distances to the core and no wrap after 8 windings.
What a big surprise for me, there is no remarkable difference to the well build unun.
The same attenuation of less the 10% from 60m to 10m.
73 Chris
2 Likes
Thank you Ignacio, that was a pleasure, of course, as almost always, with a wink.
As you can see from some contributions in this thread, your fear is unfortunately true, without any inhibitions and probably as a result of a lack of understanding (technical, linguistic).
How can one simply ignore the many expert considerations and suggestions for improvement that Owen Duffy has made in several publications?
How can one, for example, simply not understand his assessment âSo despite its popularity, this is an appalling design. It has high loss due to insufficient turns, and high leakage inductance due to winding layoutâ?
This is really a shame and is not at all what I wanted to achieve with the reference in this thread.
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