I'd always judged this on experience, and considered there was little or no difference in the noise floor. But that's no way to go about science, so I set off for a very brief session of noise assessment this evening.
A quick noise floor assessment at the beach, looking landward (East). |
I used a Windows 10 laptop to run SDRUno software, coupled to a RSP1a receiver and a 14MHz, 1/4 wave elevated vertical with two elevated radials for both sites.
I wouldn't claim that the result is accurate in absolute terms, not least because there is always a fair bit of fluctuation in the output. But I think it is, as a comparison between sites, perfectly valid. I kept the settings exactly the same for both sites, over a bandwidth of 1800Hz. The weather was electrically quiet, nearest lightning slight, over eastern Europe and central Spain, a fine sunny day with a gentle breeze.
The result?
Home noise floor, with LED TV on in the living room, various other domestic things, but none of a known noise-generating nature: -110dBm (a 'rural' noise level, according to the ITU).
At the beach: -111dBm.
It seems my ears are pretty good at comparing the noise floors! From the more considered online discussions, it seems the RSP1a itself, when using a terminated input, yields a noise floor of about -120dBm.
ITU Noise floor classifications. |
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