I tried encapsulating the ferrite rod transformer using aluminum foil but the outcome was pathetic. Instead of improving the reception, I got very poor signal. So, my conclusion is that the ferrite rod is not working as a transformer here, but it's working like a supporting loop antenna along with the main loop. that's why covering the ferrite loop stick reduces signal. BTW, there is no point of caring about signal interferences because even if I use a toroid or won't use anything at all, the main loop will still pick up the noise. So, keeping the ferrite loop stick along with the main loop would only improve the signal strength.
Signal improvement using a ferrite rod with a small loop antenna
I think you’re making wrong assumptions here. Ferrite, iron and some other materials will increase inductance of a coil. Aluminum, brass and some other non ferrous metals will reduce inductance when placed near a coil. Wrapping a ferrite rod transformer with aluminum foil will certainly reduce its inductance and cause other problems. Placing the same ferrite rod transformer inside an aluminum box where the aluminum is not touching the transformer will have little operational effect on it and will shield it somewhat.
Your ferrite transformer may be acting like an antenna but since it’s not tuned it will be a very poor performing antenna and probably not add anything to reception from an antenna standpoint. If I take my tuned 16” ferrite rod antenna and remove the capacitor making it more of a transformer, reception goes to zero, probably loosing 40dB of signal. So basically a bunch of random wire for the primary and secondary on a ferrite rode does not make an antenna that is useful.
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As I said, you can't make a transformer using a ferrite rod. I was wrong and now I came to know that a ferrite rod will only act as an antenna only. So, even you keep it in a aluminum box, it's not going to work as a transformer. I tried that too and that doesn't work. However, if you connect another loop antenna with it then it works as a booster antenna in combination.
It's not required to be tuned because I am using a variable cap and it can be adjusted to match with any radio receiver. I have tried on an AM receiver and a SDR RTL and it works. So, I don't think that my innovation is a crap.
Ferrite rods have been pretty standard for making RF transformers and baluns for probably 70yrs. I have some from Hy-Gain, W2AU and others using a ferrite rod. And you’re making wrong assumptions on how your setup is working.
Maybe ferrite rods are used as a balun but still they will pickup signal like an antenna and I believe that using a toroid will be a perfect transformer. BTW, the ones shown by you are not using any conductive espousers at all. So, I think you don't need any encloser for a transformer.
The reason why 4:1 ferrite stick would be a best choice (not as a transformer) for using with a loop antenna to match with any AM radio because the impedance ratio of 16:1 will give maximum outcome on most impedance mismatches. It's like using a maximum amps of charger available in the market for charging any type of a phone.
Maximum signal transfer happens when impedances are matched, not when you have the highest impedance and is in no way related to the available current from a cell phone charger. From your statements we can see you’re just guessing how things work and that’s not a good place to be when building antenna stuff.
The primary coil of a ferrite rod antenna along with the tuning capacitor determines the resonant frequency and the secondary coil both couples signal to the radio and also affects impedance matching. If you built the antenna right it should not require any transformer between the antenna and radio input.
That's not true, and things that happen in the real world is different from the antenna theory. I tried creating a small loop antenna for my AM radio but even if it worked without a ferrite rod, the signal was weak. But when I used a ferrite road antenna with a ferrite rod transformer (16:1), the reception was mind blowing.
I know that to get a good SWR value below 2, the impedance should match. But there is a catch with 16:1. I won't take the impedance of the main loop for granted because that could be anything. But the transmission line will be connected to radio using either coax connectors (50 ohms) or twin lead (200 ohms). Now, incase of 50 ohms, the antenna needs to be 16 x 50 = 800 ohms (for 16:1 transformer), but what if the impedance is higher than 800 ohms. Even if it's 1600, the output will be 100 ohms. So, a higher impedance won't cause much problem for 50 ohms but less than 50 ohms will be a problem.
But for the AM, a 200 ohms connector is used because 16 x 200 = 3200 ohms or higher impedance loop antenna can be used.
But if I am not using 16:1 then I might need to use only a 200 ohms antenna and that may not be having too many windings to get good reception.
That's why a 16:1 transformer can let you connect a higher impedance antenna.
You say that maximum signal transfer does not happen when impedances are matched? Since when can you change the laws of physics?
Say, you have two balls---ball A(100 g) and B (200 g) of weight. Keep them on a see saw. No matter on which side you keep them, ball A will go up and B will go down. So, higher winding means it will generate more voltage from the radio waves and that will able to push the signals further on a transmission line.
A mismatch in impedance would only matter if the lower impedance is on the load side.
Not sure where your getting your information but its not correct. Maybe this will help you understand that maximum signal (power) is transferred when impedances are matched, even with a simple battery and resistor where you would think a lower resistance would transfer more power. Maximum power in that case is when the load matches the internal impedance of the battery. I didn't believe that in my High School electronics class but after the instructor filled up a blackboard with calculations I gave in. That was 50+ yrs ago.
Maximum power transfer theorem - Wikipedia
You can't compare the ohms of a resistor with the ohms of impedance. If I am wrong then why it's a thumb rule for the audio amplifiers not to use any speaker with a lower impedance value? In any audio amp you can connect speakers with higher ohms but can't use a speak with lower than the matching impedance (ohms).Not sure where your getting your information but its not correct. Maybe this will help you understand that maximum signal (power) is transferred when impedances are matched, even with a simple battery and resistor where you would think a lower resistance would transfer more power. Maximum power in that case is when the load matches the internal impedance of the battery. I didn't believe that in my High School electronics class but after the instructor filled up a blackboard with calculations I gave in. That was 50+ yrs ago.
Maximum power transfer theorem - Wikipedia
en.wikipedia.org
When discussing maximum power transfer, circuit resistance (DC) and impedance (AC) follow the same rules. Where did you go to school to learn whatever your believing? Or what industry do you work in where you have experience and knowledge of this? Or are you making it up as you go???
Normally I wouldn't care what you think but your on a public forum where others might be influenced by wrong information.
impedance and resistance are two different things and doesn't follow the same rules. Resistance follow ohms law but impedance doesn't. Resistance is for both AC and DC but impedance is only for AC. Resistance causes change in voltage because of the change in current. The change can be constant for DC but not for AC. That's why impedance is applicable for AC. In case of alternating current, magnetic fields and capacitance of any conductor can affect the VC voltage in a conductor. That's why impedance is only applicable for AC. Higher impedance means low AC power.
That doesn't change the fact that maximin power transfer happens when impedances are matched in an AC circuit and in a DC circuit when input and output resistances are matched. You can rationalize and guess all you want but its still a fact.
Yes, impedance matching in AC circuit results in maximum performance. To keep the SWR value less than 1.5, impedance matching is require red. You need to do more homework on this rather than arguing with me.
Suggestion #1: Listen to prcguy.
Suggestion #2: Find some of the many documents available on the Web regarding use of ferrite rod antennas for hobby LF reception. AM BCB reception works using the same techniques.
Suggestion #2: Find some of the many documents available on the Web regarding use of ferrite rod antennas for hobby LF reception. AM BCB reception works using the same techniques.
prcguy may be right, but what I made, really works for me. Whether you write 1 + 2 or 2 + 1, the answer will always be 3.
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