A Bias-T and active antenna performance
edited February 2018 in Installation, Antennas and Interference
Working with the Home Brew Shielded Magnetic Loop has led me to want a Bias T that will work from 15KHz to 32MHz. I have the input side from another commercial loop antenna and just as a guess I placed a 1 mH inductor from the coax input to the +vdc on the Hiletgo LNA board and that works to power the amp and push signal down the coax. The circuit from the LNA is a 10pF capacitor to the 1mH choke and the coax center conductor. The self resonance of the 1mH choke is stated at 1MHz and the calculated resonance of the capacitor/inductor circuit is 1591.549KHz.
I wonder what affect this will have on the antenna. By observation I do not see the affect on the waterfall, but I have not cross checked with providing power from a VDC source not carried by the feedline.
Will a Bias-T notch frequencies at the resonant points?
Will feed back from the Bias-T cause oscillations and harmonic generation through the LNA?
I'm not seeing this, but just wonder what to consider when setting up a Bias-T to operate from 15KHz through 32MHz.
This Bias-T circuit is currently in service at http://ka7u.no-ip.org:8073