Iridium (L-band): Frequency around 1.6 GHz. This is the golden band in the spectrum, with extremely strong signal penetration, easily passing through clouds, rain, and even reaching indoors. More importantly, the L-band is globally scarce and was specifically allocated by the ITU for mobile satellite communications, making it irreplaceable by terrestrial 5G and highly exclusive.

PL (mainly X-band, S-band): Frequency around 2-8 GHz. Although the bandwidth is wider than the L-band, allowing for more data transmission, the penetration is poor and easily affected by weather. More critically, these frequency bands overlap with many terrestrial communications (such as some 5G bands), posing a high risk of interference and relatively strong substitutability.

Iridium's L-band: Due to extreme global scarcity, the implied value of the spectrum license alone in the international black market or asset transactions is extremely high. Industry estimates suggest the value per MHz of the L-band could be 3-5 times that of X/S bands; Planet Labs: Although it also holds legal authorization, its frequency bands are not on the same level as Iridium's L-band in terms of scarcity and exclusivity.

Therefore, even disregarding the business model, just considering the spectrum itself, what Iridium holds is like prime real estate in the core area of a tier-1 city, while what PL holds is more like industrial land in tier-2 or tier-3 cities, supplied on demand. The price per square meter of the two naturally differs by several grades.

$Iridium Comm(IRDM.US)

$Planet Labs(PL.US)