https://www.rfwireless-world.com/calculators/Horn-Antenna-Calculator.html https://www.rfwireless-world.com/calculators/Horn-Antenna-Ca... for instance. Put in

https://www.rfwireless-world.com/calculators/Horn-Antenna-Calculator.html https://www.rfwireless-world.com/calculators/Horn-Antenna-Ca... for instance. Put in a 3 by 5 meter aperture, and bam, 40dB on the nose.