-140 dBm is far beyond no coverage, yeah. -120 dBm is pretty much when LTE stops working (sometimes it can painfully stretch to -123 to -125 but usually not because of noise etc)

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ac29 4 days ago | parent [-]

Yes, even thermal background noise (the noise level that exists even in complete absence of RF) would be expected to be above -140dBm. It scales with channel size and temperature.

As near as I can tell, the smallest subcarrier 5G can use is 15kHz, the thermal noise floor for a 15kHz channel at room temp (300K) would be -132 dBm.

My guess is whatever chip doing the measurement simply couldn't measure that low accurately, or it reports "nothing detected" as -140 dBm.

	▲	userbinator 3 days ago \| parent \| next [-]
		GPS receivers can go down to around -160dBm, but that's a very low bitrate signal. Nonetheless it is possible to receive such signals via CDMA techniques.
	▲	throwaway270925 3 days ago \| parent \| prev [-]
		Reminds me of "The Hunt For Red October" and the sonar consoles "magma displacement" reportings...