# Tag Info

Accepted

### How to measuring ferrite core efficiency vs frequency

To help identify a mystery ferrite core mix, the most common method is to take some measurements to determine the initial permeability (µi). Then compare your results to a table of µi for common core ...
• 138
Accepted

### How does a loopstick antenna actually receive signal?

The basic operation can be understood by Faraday's law of induction. Any loop of wire will exhibit an electromotive force proportional to the rate of change of magnetic flux encircled by it. Since any ...
• 49.8k
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### Can ferrite beads lower coax cable velocity factor?

No, adding ferrite beads to choke currents on the outside of the shield of a coaxial cable does not affect its impedance or velocity factor. Impedance and velocity factor are determined by the inside ...
• 7,685

### Why are loopstick ferrite antennas commonly wound with Litz wire?

The advantage of Litz wire —lower loss than solid wire— is realized below about 1 MHz. It is of little use above 160 meters. From https://en.m.wikipedia.org/wiki/Litz_wire Litz wire is a particular ...
• 7,485

### Can ferrite beads lower coax cable velocity factor?

For well-designed coax, the EM fields are confined to the space between the inside of the braid and the center conductor, i.e. the dielectric insulation region which affects the velocity factor. ...
• 1,646

• 7,685
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### Can a slinky serve as a ferrite core and if so, is there a prefered configuration?

A ferrite core used for radio is specially constructed to conduct magnetic fields while not conducting electrical current, especially eddy currents. A slinky is (typically) an uninsulated conductive ...
• 4,168

### Is this the Correct Ferrite Core to Reduce RFI as a Common Mode Choke?

That does look like a fine core to use, and the photo of your construction looks good. Your coax isn't causing any problems with noise. Try putting the choke at the feedpoint, not at the radio, in ...
• 49.8k
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### Is this true about ferrite loop antennas?

Now if I imagine the coil without the ferrite but I multiply the area by 1000, that will be a huge area, how can it be 1000 times more power? Because, as the article says, the magnetic permeability ...
• 49.8k

### How to effectively test and interpret the "working range" of a ferrite core with a signal analyzer?

So the problem here is that your setup is not sufficient to tell you what you want to know about the ferrite core. In my set up I have a ferrite core where I made a number of turns on. I connected ...

### Importance of Ferrite Size in Coax Choke Balun

I believe the choice of the core size is twofold. As from K8NVH good answer a minimum impedance is needed for the balun to do its job. A common mode impedance much higher than differtial ones ...
• 171

### Is this the Correct Ferrite Core to Reduce RFI as a Common Mode Choke?

The answers here are excellent and I have little to add other than to emphasise / RFI problems are hard / Consider the case of the RFI problem discussed in Electronics Stack Exchange ( https://...
• 1,022

### Can ferrite rod antenna be made out of the choke?

A ferrite rod antenna is a small loop antenna, just with more than one turn (usually lots more), and wrapped around something with a relative permeability of greater than one (usually much greater). ...
• 12.4k
Accepted

### Do a toroid's specs matter much in an antenna matching transformer?

Transformers are inductors. They just happen to have mutual inductance with another inductor. Like inductors, they also have self-capacitance, and so a resonant frequency. They also have loss, and ...
• 49.8k
Accepted

### How to make a ferrite bar antenna for RTL-SDR?

Looking at an Amazon listing, it appears that the Degen 31MS active antenna has three ways to connect to a radio. The first is via a direct ANT jack, the second is via clips to existing wire (likely ...

### Ferrite rod or core permeability determination

Because ferrites aren’t marked, it is difficult to know what frequencies they work on. However, now we can use the popular NanoVNA along with free software (and Excel) to graph the unknown ferrite’s ...
• 7,485