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Author Topic: Crazy big Magnetic Loop Antenna  (Read 999 times)

Offline kris

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Crazy big Magnetic Loop Antenna
« on: August 24, 2023, 2125 UTC »
    An interesting idea for broadcasters and maybe SWL!
https://www.youtube.com/watch?v=R71qeIq5WKs
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Offline KandiKlover

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Re: Crazy big Magnetic Loop Antenna
« Reply #1 on: September 10, 2023, 2244 UTC »
No point in one for broadcasting since you're transmitting only there's no need to filter out the electric part of the electromagnetic spectrum. A regular small transmitting loop in this size though for a little backyard piracy with the ole 400 watt broadcast transmitter wouldn't be a bad idea though. 45 meters and lower would give decent NVIS coverage over the state by day and the neighboring states by night.

Offline ChrisSmolinski

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Re: Crazy big Magnetic Loop Antenna
« Reply #2 on: September 11, 2023, 1327 UTC »
There's a good technical description of how "magnetic" loop antennas work here: https://www.w8ji.com/magnetic_receiving_loops.htm

Spoiler Alert: They don't really filter out the electric portion of the wave and only receive the magnetic. They don't even work like most folks selling/describing them claim.
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Offline Ed H

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Re: Crazy big Magnetic Loop Antenna
« Reply #3 on: December 21, 2023, 2039 UTC »
I know this conversation is a bit old, but small ferrite loop antennas can transmit after a fashion. A few years ago, I cajoled our son into a radio project for the science fair. We made a part 15 transmitter, working at the top of the AM broadcast band, and tested some different antennas. One of these was a ferrrite rod resonated with a variable cap, and a small winding coupling to it from the transmitter. It worked quite well, although not as well as a coil loaded 10ft vertical.  We were trying to stick within the spirit of Part 15 regulations for power and antenna size. Part of this was that with tight coupling, the antenna pulled the transmitter oscillator, so it was hard to get it perfectly on tune for full efficiency.

I mean to test this again one day, just for fun, using some more stable hardware.

 


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