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You'll find voltage baluns in plenty of circuits. For example, the QRP Labs receiver module: HPSDR Pennywhistle (twice, T1 and T3): The Elecraft KX3: A voltage balun can do some things a current balun can not. Firstly, the turns ratio can be varied to provide impedance transformation. Some of these circuits use something other than a 1:1 turns ratio to ...


6

By the principle of reciprocity, if it works for transmit, it works for receive also. Possibly if your receiver and transmitter are separate devices you may end up with a situation where no common-mode current was detectable on transmit, and yet common-mode signals did appear in the receiver. However with modern equipment having both receiver and transmitter ...


5

When making a coax choke balun, does the size of the ferrite matter, and if so, why? Simplest answer: If the choke impedance is low enough to allow some common mode power through, then there is a possibility of overheating. The bigger cores either dissipate heat better or provide higher impedance. Another way to say the same thing: As long as the choke ...


2

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 involved makes sure the balanced to/from unbalanced convertion takes place. This somehow drives the size of the core for its mechanical dimensions shall allow the ...


2

Magnetic loops do not need a choke more than other kinds of antennas but I recommend you have one anyway especially if you will have coax running through your house. The reason to have a choke with a magloop is to reduce rf receive noise which can be picked up by the coax from local rf noise sources in your house. This is also valid for other types of ...


2

I attended a seminar on baluns --as applied to antennas-- at a local hamfest, given by no less a guru than Glenn Shultz, W9IQ. He nicely explained that the only place we need to use a voltage balun in an antenna system is for end-fed antennas. Every place else, use a current balun. And the simpler, the better.


1

The very best source of information that you'll find about making common-mode chokes is available at Jim Brown, K9YC's site http://k9yc.com/publish.htm. Download his PDF http://k9yc.com/RFI-Ham.pdf. RFI, Ferrites, and Common Mode Chokes For Hams Most recent update April 2019. This tutorial is directed specifically to RFI in ham radio applications. It ...


1

You build a few and measure them with a vector impedance meter.


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