SITOR – Simplex Teletype Over Radio. If Morse was the “heartbeat” and SSB was the “voice,” then SITOR (Simplex Teletype Over Radio) was the “logic” that bridged the gap between the era of the brass key and the age of the computer.

From Ionosphere to Orbit – Every great era has its sunset. For the maritime Radio Officer, that sunset began to glow in the late 1990s. As we close our series at Parts-Ring.com, we look at the moment the world’s ears moved from the shifting layers of the atmosphere to the steady, cold precision of space.

Guardians of SOLAS – In the romanticized world of maritime radio, we often focus on the powerful signals and long-distance contacts. But for a Radio Officer, the most critical duty often involved absolute silence. This was the practice of the “Silent Periods” on 2182 kHz (MF) and 500 kHz (HF)—the core of SOLAS (Safety of Life at Sea) in the pre-satellite era.

The Indestructible Beep – In our previous posts, we talked about the “Heavy Iron” and the complex math of SSB. But if you strip away the power amplifiers and the sideband filters, you are left with the purest form of communication ever devised: The Continuous Wave (CW).

Tools of the Trade – In our previous posts, we talked about the physics of the sky and the math of the signal. But on the bridge of a Merchant Navy vessel, physics and math had to be housed in steel.

As a Radio Officer, your gear was your lifeline. If you were sailing with Marconi or JRC (Japan Radio Co.), you weren’t just using a radio; you were commanding a masterpiece of industrial engineering.