Jammed Net at 0400

Diagnosis: work from yourself outward before you conclude the enemy is jamming.

The sweeping tone plus total silence is consistent with several causes, and the order in which you check them matters because the cheap fixes are the most common:

1. Your own equipment. Power, battery, antenna connection, correct frequency and hopset, correct COMSEC fill loaded and not expired. A radio that has silently dropped out of hopset can sound like jamming to the operator.
2. Terrain masking. The TOC is in a draw. VHF is line-of-sight; the draw plus 4 kilometers of ridge is a plausible reason one station cannot hear you, though it does not explain the tone.
3. Net discipline or a station stuck in transmit. A stuck transmitter or a hot mic produces a carrier that blocks the net.
4. Interference or jamming. A steady sweep is a classic sign of a sweep or barrage jammer rather than random noise. Treat it as a working assumption, not a certainty.

Immediate sequence:

• Do not keep calling on the same frequency. Every unanswered call confirms nothing and burns time.
• Shift to the alternate frequency from the SOI and make a brief, disciplined call. If that fails, go to the backup frequency.
• Move the antenna: get out of the draw, use the vehicle radio as a second asset, or send a runner to the commander's vehicle.
• Consider a hilltop relay or a third station acting as a retrans, if authorized.
• Report the interference up the chain per the MIJI (meaconing, intrusion, jamming, interference) procedure.

Key judgment: the commander's 0500 deadline is a planning constraint, not a reason to stay on a dead frequency. Frequency agility is the point of the hopset and the SOI.

Pass it correctly the first time, because you may not get a second chance.

Procedure:

• Use the standard sequence: call sign of the station called, "this is," your call sign, "over." Wait for the reply before transmitting the message.
• Authenticate before passing anything sensitive. Use the authentication table from the SOI, not the challenge and password over the net in the clear, and not the same challenge twice in a row.
• Keep the message short and unambiguous: what changes, where, when it takes effect, and what each element must do. The commander's intent in plain language beats a clever abbreviation the other end has to decode.
• Close the loop. Require a read-back of the critical items - time, location, and action - rather than accepting "roger." "Roger" means received; "wilco" means will comply. They are not the same and should not be used interchangeably.
• If a station is not answering, use a third station as a relay only if the SOI or the commander authorizes it, and tell the relay exactly what to pass.

For the missing platoon:

• Try its alternate and backup frequencies, and try at the scheduled 0430 net check.
• Ask the two stations that are up whether they can raise it on their own radios - terrain differs by location, and a station on the ridge may reach it.
• If the change is time-critical and cannot be relayed, tell the commander that the platoon will execute the old plan at 0500 and recommend a physical runner or a shift of the timeline.

What not to do: do not broadcast unit locations, casualty information, or frequencies in the clear; do not read out authentication material twice; do not transmit the change in fragments that invite misunderstanding.

Record in the radio log, contemporaneously:

• Time each transmission began and ended.
• Frequency or net used.
• Stations called and stations heard.
• A short summary of message content and whether a read-back was received.
• The time and nature of the interference, including the frequency, the sound, direction if known, and duration.
• Every action taken: alternate frequency, backup frequency, relay, antenna move, and the result.

Report to higher:

• A MIJI report through the operations channel: what was affected, when, on what frequency, and what you did about it.
• A short SITREP to the commander on which elements received the change and which did not, so the commander can adjust the plan rather than assume it was received everywhere.
• The fact that the net remains degraded, even after it appears to recover.

Stays off the air:

• Unit designations and grid locations in the clear.
• Names of casualties or personnel status.
• Frequencies, hopset data, COMSEC fill information, and authentication tables.
• Speculation about who is jamming you, and any discussion of the interference on the net itself. Announcing "we are being jammed" on an open channel tells the jammer they succeeded and tells anyone listening that your net is degraded.

Judgment point: the report and the log are not paperwork for its own sake. Interference patterns across a battalion - which nets, which times, which terrain - are what let a signal officer locate a jammer or confirm an equipment fault. A vague log entry makes that analysis impossible.