A major satellite-to-phone network has just been given FCC approval to expand its low-Earth-orbit constellation — and part of the decision touches a band every 70 cm operator should care about.
The company is AST SpaceMobile, and its planned constellation is designed to provide direct-to-device cellular coverage from space. In plain English, that means ordinary mobile phones connecting through satellites where normal ground-based coverage is poor or unavailable.
That part is impressive technology. But here is the radio angle.
The FCC authorization also allows limited use of the 430–440 MHz amateur band for satellite telemetry, tracking and command — often shortened to TT&C.
That does not mean normal mobile phone traffic is being carried on 430 MHz.
The main direct-to-device service is based around commercial cellular spectrum, including 700 MHz and 800 MHz bands in the United States. The 430–440 MHz use is listed for emergency satellite control and tracking, using narrow 50 kHz channels centered on:
- 430.5 MHz
- 432.3 MHz
- 434.1 MHz
- 435.9 MHz
- 439.5 MHz
The FCC wording limits this use to emergency/non-earth-pointing TT&C, and for the additional satellites the use is limited to a period not exceeding 24 hours.
So why are radio amateurs concerned? Read full post
