I must be missing something. The noise in a 50 ohm resistor is -174 dbm per root Hz at ambient temp.
Lets take 100Hz bandwidth for the receiver and the noise becomes -154 dbm or .0045 uVolts Lets add a PERFECT amplifier of 40 db. The noise output of the 40 db amp is then -114 dbm or 0.446 uVolts S-2 on a receiver with perfect S meter is .4 uVolts so the RX should set at S-2 normally. As I understand it the Waller antenna produces about -45 db of gain over some reference. (45 db Is 177 time voltage) So in order to simply match the noise level of .446 uVolts with a signal you need a signal impinging on this antenna that would produce 79 uVolts in an antenna similar to the reference. To me a signal of 79 uVolts is something over S-9 on a receiver. Would a simple dipole or inverted Vee antenna with essentially no gain produce a whopping signal from the same source. Of course it would pick up noise as well but I would think it would not be of an equal S-9 level. Where did I go wrong in these figures. I must be astray somewhere. Lee K7TJR OR _________________ Topband Reflector Archives - http://www.contesting.com/_topband
