I don't believe that is necessarily true, Roger. If the noise it truly
omni-directional, a directional receive antenna can still increase SNR
because it increases the amount of signal captured compared to the
amount of noise captured. The reason for this is that for
omni-directional noise, the increase in directivity robs Peter to pay
Paul, so the total noise power received remains constant whereas the
increased directivity (assuming it is in the direction of the desired
signal) increases the desired signal power received.
OTOH, if you have a dominant noise source in the direction of the
desired signal, you are out of luck unless you can take advantage of
difference in polarization the way that N4IS does with his horizontal
waller flag.
73, Mike W4EF.....................
On 11/27/2024 1:44 PM, Roger Kennedy wrote:
However, the general noise level EVERYWHERE here in Britain is around S7
these days - that's on 160m 80m & 40m. That's in an SSB Bandwidth, and with
an accurate S Meter. And because the noise comes from every direction, no
phasing unit or directional receiving aerial will help reduce it.
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