On Tue, Feb 21, 2023 at 05:46 PM, vbifyz wrote:
The input filtering may need more work to handle strong nearby broadcast stations better.
Hi Mike,
A good project.
I'm a bit concerned about the value of the input capacitors which are shown as being 1nF, with a comment to reduce them to 100pF if there are no strong FM stations nearby.
Using 1nF capacitors a typical 1m diameter loop, having an inductance value around 2.5uH, will bring the loop to resonance at around 4MHz, which is not desirable if you wish to have good performance over a wide frequency range.
Ideally the value of the input capacitors (and resistors) should be chosen in conjunction with the actual value of loop inductance, in order to provide a suitable matched characteristic and impedance tracking across the whole of the desired frequency range.
Some further notes on this subject can be found here.
Good luck with your project.
Regards,
Martin
