[Antennas] Receive vs Transmit

2003年2月16日 14:03:12 EST

I think there are two reasons why receiving with untuned antennas is not as 
much of an issue: First, as you point out, many older receivers have an 
antenna trimmer which will cancel out at least part of the mismatch between 
antenna and receiver. Second, your sensitivity, especially on the lower 
bands, is limited by external noise. So if I have a "broadband" antenna with 
10 dB of loss, it will not affect my reception provided the external noise is 
at least 10 dB above receiver noise floor. (My experience at my suburban 
location is that I've got at least 10 dB above receiver noise up through 20 
meters). The S meter will be 10 dB lower than with a good antenna, but the 
signal to noise is still about the same. On transmit, however, you've got to 
exceed the external noise at the other guy's location, so if you lose 10 dB, 
he may not be able to hear you.
Ed WB2LHI