I would say my favorite monitoring subject is military comms and UHF Satcom
Satcom part 1 par Nobody - Fichier PDF
OSA | Radiation pattern of planar optoelectronic antennas for broadband continuous-wave terahertz emission
Military SATCOM Ground Station Antenna SATCOM X Wing Antenna Ground-To-Air Antenna satcom Satcom Extended range antenna Right Hand Circular Satcom Antenna SATCOM Helical ANtenna SATCOM linear vertical polarized satcom antenna UHF satcom