I was looking for a 2.4 GHz WiFi antenna to catch a weak free WiFi signal, and amplify it so I can use it. I found Ruckus Metroflex NG, which can receive signals down to -108 dBm. Which is amazingly weak; however, while searching for such an antenna, I couldn't help noticing that 900 MHz receivers, such as LoRaWAN have a sensitivity down to -136 dBm. This is literally weak enough that at 1W transmission power, you can catch the 900 MHz signals of anything you can see on earth -- even of the highest planes.
So I thought, OK, the lower the frequency, the longer the waves, and the easier to catch them. But apparently, that's not the case. GPS receivers, which operate at the intermediate frequency of 1.575 GHz, go down to a whopping -164 dBm acquisition sensitivity for the RXM-GNSS-TM-B (and even lower tracking sensitivity). So, what gives? Why is there such a huge discrepancy in the required strength of a signal before it's detected?