The sensitivity is measured through a cable: this way you get an accurate measurement of performance, independent of external condition. But, if you see a better sensitivity in a product compare to another, it basically means that you need less SNR for the same performance, and so this should translate as well in real life.
But in this particular case, don’t be fooled by the front-page datasheet number: the sensitivity given is basically the lowest achievable with the chip, but the condition can be very different:
- looking at the SX1301 datasheet if you use the reference design you get -139.5 dBm and not the -142dBm (this one might require an external LNA I believe, so it depends on the product.
- If you look at SX1276 you can see -146dBm sensitivity, but here, it is because the lowest bandwidth is different…
- And even the definition can be different: the gateway sensitivity is for 10% PER , CR 4/5 and 32B while for the 1272 it is 1% for code rate 4/6 and 10B
In the end, it is difficult to fully compare both because the node contains the radio while the gateway depends of external front-end: so on a gateway you can get very different performances depending of the front-end used, presence of external LNA, … But at the LoRa demodulator level, those two chip are basically the same.