[nrv-hams] Mag Loop Antenna Follow-up

[J.C. Hassall]

Great info Cam, tnx. I’m looking for good antenna ideas and this seems like a great start

jim

Fat-thumbed from my iPhone7

> On Oct 29, 2019, at 9:30 AM, Cam Coble <cam at doubleclickdata.com> wrote:
> 
> As a follow-up to the antenna show-n-tell, I wanted to provide some
> resources and information in regards to the magnetic loop antenna.
> 
> Two mentioned informative videos:
> Jeri Ellsworth - AI6TK
> Magnetic Loop Antenna Current and Voltage Distribution
> https://www.youtube.com/watch?v=adJp1zO9qfo
> 
> Peter Parker - VK3YE
> 100 watt 7 MHz magnetic loop for units and apartments
> Uses blank copper boards for variable capacitor
> https://www.youtube.com/watch?v=Cv_RnLpZ9gw
> 
> A video about mag loop antenna height:
> Kevin Loughin - KB9RLW
> Magnetic loops and height. Do they change near to the ground?
> https://www.youtube.com/watch?v=AWttibCYn1U
> 
> 
> Calculator I used for my loop
> http://www.66pacific.com/calculators/small-transmitting-loop-antenna-calculator.aspx
> 
> My specs are 9 foot loop circumference, 1" conductor, targeted for 14Mhz,
> and 5 watts.
> This calculated to the specs below. Note the high Q factor and RMS volts
> generated from 5 watts (15.81 Vrms)!
> 
> Antenna efficiency: 59% (-2.3 dB below 100%)
> Antenna bandwidth: 13.2 kHz
> Tuning Capacitance: 65 pF
> Capacitor voltage: 959 volts RMS
> Resonant circulating current: 5.52 A
> Radiation resistance: 0.048 ohms
> Loss Resistance: 0.034 ohms
> Inductance: 1.98 microhenrys
> Inductive Reactance: 174 ohms
> Quality Factor (Q): 1,059
> Distributed capacity: 7 pF
> 
> Want to know more about the impact of the Q factor?
> https://hamradioschool.com/antenna-q-factor/
> 
> Let me know if you decide to build your own! You may have some ideas I can
> use ;)
> 
> Thanks and 73!
> --
> Cam - W4XXV
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