Passive antenna
Hello, I would like to know what needs to be done in order to use a passive loop antenna with the Kiwi, eg is a balun needed Many thanks in advance.
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Hello, I would like to know what needs to be done in order to use a passive loop antenna with the Kiwi, eg is a balun needed Many thanks in advance.
Comments
You might need to throw us a bit more of a bone here.
What is your intention, and why a passive look?
Airspy have a magloop
Unless I am missing something, a passive loop vs a magnetic loop will not likely give you any advantages over a long wire.
IMO you are missing something. Necessary to remove CM <==> differential coupling (asymmetry) in the antenna system. CM ground currents, and asymmetry mean that unwanted noise degrades the desired antenna signal.
A balanced dipole or loop starts out in a better place. That symmetry needs to be maintained so they don't guarantee it, easy to lose it in an intervening transmission line - e.g. coax doesn't help but balanced line does . Bone.
If you want your loop to be broadband, that is to cover the bandwidth of the Kiwisdr, then a balun isn't needed. However we don't know the size of your loop, so depending on its size you may find you need some form of matching transformer, be it a balun or an unun, etc. How long is a piece of string?
You don't mention the size of the loop you intend to use, but in most cases it will require a balanced amplifier (or an unbalanced amplifier and a balun), with a low noise figure and about 20dB gain, to provide a sufficient degree of sensitivity for use with a KiWi.
If you are interested in such designs, I suggest you join the LoopAntennas IO group, which contains a welath of information.
https://groups.io/g/loopantennas
Regards,
Martin