Use for extra toroids?

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Posts: 5
Joined: 21 Apr 2022, 02:45

Use for extra toroids?

Post by Lukekg5wjz »

So slightly off topic, but I received a few extra toroids with my kit. Are these suitable for a little 9:1 for an efrw to go with the radio? Or an efhw? Any other suggestions for something I could do with them?

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Joined: 03 Jan 2022, 21:11
Location: Krakow

Re: Use for extra toroids?

Post by SP9TKW »

You can make EFHW out of #43 material. If you have spare FT37-43 you would need 28:4turns, I suggest to make autotransformer ie wind 28 turns and make tap on the 4th turn. Have a look at YouTube K6ARK channel he makes quite interesting version.

If you have T37-2 then you could try to make Long Wire antenna with 9:1, however I am not up to speed with this type of end fed.

Good luck

73 Marek

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Joined: 07 Aug 2022, 23:42

Re: Use for extra toroids?

Post by KO4TCY »

How did you calculate the required turns for the FT37-43 cores?

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Joined: 30 Dec 2021, 19:18

Re: Use for extra toroids?

Post by DL2MAN »

I've tested very recently the the use of various efhw transformer core sizes (including ft37).
You might want to watch this:

And the video before explained the theory of the efhw and how to wind the transformer. Also worth watching if you're not familiar with this antenna:

73 Manuel DL2MAN

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Joined: 30 Dec 2021, 21:39
Location: FN25eg

Re: Use for extra toroids?

Post by va3rr »

You can make an EFHW tuner with the powder core toroids, but you might want to stack 2 of them.

Slava Ukraini!
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