https://m1kta-qrp.blogspot.com/2010/01/501-504khz-lo-for-field-strength-meter.html
M1KTA's QRP ham radio blog: 501-504kHz LO for Field Strength Meter
As per previous post about 500KHz ( http://m1kta-qrp.blogspot.com/2010/01/500khz.html ), based loosely on PA0SE field strength meter which i...