Signal improvement using a ferrite rod with a small loop antenna

ofosot69

Member
Joined
Jul 20, 2024
Messages
5
I have used my small loop antenna (which has a main loop and a coupling loop that can be tuned using a variable capacitor) with an AM radio receiver to receive MW broadcasts. However, the small loop antenna which was made by me was not working properly but when I connected a ferrite rod loop (which has two windings on it---one with 60 turns and the other with 30), I saw a great improvement in radio reception. I connected the 60 turns loop with the main loop of the small loop antenna and the 30 turns loop with the AM radio.

The ferrite loop is not working as an antenna and when I turned it, I didn't get any difference in signal strength. However, when I turned the small loop antenna, I saw the change in signal.

So, I need to know why this has happened and did the ferrite rod work like a balun?

I have attached the diagram of the setup.
 

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timetraveller

Newbie
Joined
Feb 9, 2022
Messages
2
Yes, the ferrite rod did work as a balun. What you've created is a 4:1 voltage, or galvanic balun. 60:30 is a turns ratio of x2. You square the ratio to get the impedance transformation factor. 2 squared = 4. The signal improved probably because of less pickup coil loading and a better match to your receiver. Good job. I've used this technique when I didn't have a spare toroid.
 

ofosot69

Member
Joined
Jul 20, 2024
Messages
5
Yes, the ferrite rod did work as a balun. What you've created is a 4:1 voltage, or galvanic balun. 60:30 is a turns ratio of x2. You square the ratio to get the impedance transformation factor. 2 squared = 4. The signal improved probably because of less pickup coil loading and a better match to your receiver. Good job. I've used this technique when I didn't have a spare toroid.
Oh... that's how you calculate 4:1? I thought it's 2:1 because it's 60:30. Now I tried another stick with 96:24 and it worked better. So, is that 8:1?
 
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