What is East/West Rule in MSK144 Meteor Scatter Communications?

| November 11, 2026 | Amateur Radio (Ham Radio) | No Comments

In VHF meteor-scatter communications using the MSK144 protocol (such as on 6 meters or 10 meters), the East/West Rule (frequently remembered by the popular amateur radio acronym PETE — Point East, Transmit Even) is a standardized operating convention designed to minimize mutual interference on crowded calling frequencies (like 50.260 MHz).

Because meteor scatter relies on rapid, short-duration bursts (“pings”) and utilizes fixed 15-second T/R (Transmit/Receive) sequences, organizing when stations transmit based on their geographic pointing direction prevents local chaos on the waterfall display.

How the Rule Works

  1. Stations Pointing / Transmitting East:
    • Transmit Cycle: Even minutes/intervals (e.g., 00, 30 seconds of a minute block, or the 0th/2nd/4th 15-second periods).
    • In WSJT-X, you check the Tx even/1st box.
  2. Stations Pointing / Transmitting West:
    • Transmit Cycle: Odd minutes/intervals (e.g., 15, 45 seconds, or the 1st/3rd 15-second periods).
    • In WSJT-X, you leave the Tx even/1st box unchecked.

Why It Matters

  • Avoiding Self-Jamming: On wide-open VHF propagation windows during major meteor showers (like the Geminids or Perseids), hundreds of operators target the same calling frequencies. If directional beams pointed in opposite directions transmitted during the same window, stations in between would experience massive overlapping QRM, masking the weak, fleeting meteor pings.
  • Streamlined Scheduling: When calling CQ, adhering to this protocol lets potential responding stations instantly know which time slot you are listening in, optimizing the handshake sequence required to complete an automated MSK144 contact.

(Note: While the rule is a foundational guideline especially prominent in North American VHF contesting and general operations, always verify regional operating habits or specific event rules before jumping onto the cluster.)

6m Meteor Scatter Communication with MSK144 This video provides a quick visual walkthrough of how MSK144 meteor scatter communication functions on the VHF bands.