Use for extra toroids?

[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?

[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

[KO4TCY]

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

[DL2MAN]

I've tested very recently the the use of various efhw transformer core sizes (including ft37).
You might want to watch this:
https://youtu.be/nNzTf1F12BE

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:
https://youtu.be/2-4J8ECkoe4

73 Manuel DL2MAN

[va3rr]

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

https://www.aa5tb.com/coupler2.html