Question 1

What is the max wattage these are rated for. i want to build an unun for  an end fed antenna that will handle 600 watts. will 1 or more handle amount?

Accepted Answer

You should use 2 for 600 watts, the highest rating I have seen for only one is 400 watts.  Based on commercial models of end-fed ununs.

Question 2

I would like to use this on the 11-meters cb band (26.965 - 27.405) will this help to cut down rf returning to the radio?

Accepted Answer

how many watts?  4 watts isn’t anything to worry about but 500+ watts certainly would be.  and yes, wound as a 1:1 choke (or they also call them current baluns) it will absolutely lessen common mode current coming back down the coax.
coax coils (mentioned in other responses) are not nearly as effective as a 240-31 ferrite core wrapped as a 1:1 current choke. google “1:1 current balun” or “1:1 current choke” and you will see many examples to guide you.  balun btw simply means balanced and unbalanced and they are used to rectify the impedance mis-match between the antenna and the 50 ohm coaxial cable. that generally involves lowering the high impedance of an antenna (200-3000 ohms depending on design) and even then, it should be referred to as a step down transformer but balun (balanced / unbalanced) has become the default term.

Question 3

Will this work to reduce/remove static noise on a regular FM radio produced from cheap led lighting in a garage?

Accepted Answer

It likely would with a couple of ifs.    It is really large for such a task.  The toroidal core would need to be  placed as close to the LED power source as possible.   Is the FM radio itself close to the LED lighting?

Question 4

Will this block interference from a treadmill motor?   Ethernet over powerline is degraded whenever the treadmill is on.

Accepted Answer

ethernet over power line is destroying the shortwave radio frequencies , you should run a real cat-5/6 cable or use 5gig wireless....
and you would only need type 73 core for anything the treadmill is hashing out on the airwaves.

ASIN	B0178IA3XU
Amazon 売れ筋ランキング	産業・研究開発用品 - 114,529位 ( 産業・研究開発用品の売れ筋ランキングを見る ) フェライトコア - 66位
Amazon.co.jp での取り扱い開始日	2016/12/23
Measurement System	メトリック
おすすめ度	4.6 5つ星のうち4.6 (457) var
サイズ	m-500
メーカー	FAIR-RITE
メーカーにより製造中止になりました	いいえ
商品の重量	118 g
商品寸法 (長さx幅x高さ)	7.6 x 2.5 x 7.6 cm
材質	フェライト
色	レッド-500
製品サイズ	7.62 x 2.54 x 7.62 cm; 118 g
部品番号	FT240-43
電池付属	いいえ
電池使用	いいえ
騒音レベル	30 デシベル

Toroid Core FT240-43 フェライト

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Common Questions