" Since Rick correctly stated that RDF doesn't account"
Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too RDF is one way to measure directivity . You may do not need directivity to improve signal to noise ratio if you are operating from a very quiet location or a desert island on the pacific without man made noise. If you deal with noise at your location you will select the antenna with better directivity. That's adds another component how to cover all directions. Better RDF equals to better signal to noise ratio. That's is true for all bands, try to work 20 meter contest with a vertical with 1 kW and compare with a 5 elements Yagi with 100W. Your TX signal will be the same however for sure you will prefer to receive on the Yagi due its directivity. You won't hear much on the vertical Regards JC N4IS _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband