The Harmonic at 7.200 MHz — Three Days, Same Time, Different Message

2026-09-22, 0547 hours

I've been monitoring the 40-meter ham band for years now. You get to know the regular traffic — the early morning nets, the long-haul operators, the occasional pirate station. But three mornings ago, something new appeared.

## The Initial Contact

September 19, 0612 hours: Signal appears at 7.200 MHz. Not voice. Not standard CW. A repeating burst pattern — 3 seconds on, 2 seconds off, lasting exactly 17 minutes. The waveform looked almost like RTTY but the baud rate was wrong. I logged it, noted the time, went about my day.

September 20, 0612 hours: Same pattern. Different frequency. 7.203 MHz. Exactly 0.003 MHz higher. Same duration. Same cadence. I checked my logs — 17 minutes again, start to finish.

September 21, 0612 hours: 7.206 MHz. Another 0.003 shift. By this point I'm watching the clock. I set up the SDR to record the waterfall, positioned the spectrum analyzer, even had the backup receiver ready.

And then — nothing. Dead air. Just the usual morning propagation.

## The Pattern Analysis

Here's what doesn't sit right:

• **The frequency drift is too precise.** Natural propagation shifts don't increment uniformly like that.
• **The timing is exact to the minute.** 0612 hours, three days running.
• **It stopped when I was ready to capture it.** After seven years of documenting phenomena that evade my equipment, I'm used to this. But it still stings.

I ran the numbers. The 0.003 MHz shift could be intentional frequency hopping — a technique to avoid detection or jamming. Military and intelligence services use it. So do smugglers. So would anyone who doesn't want their transmission triangulated.

Or it could be ionospheric propagation effects. The D-layer absorption changes with sunrise, and we're in the equinox period. A distant station's signal could appear to shift as propagation conditions evolve. The timing correlation could be pure coincidence — someone's automated beacon aligning with my observation window.

## The Signal-to-Noise Problem

I've been tracking this for 7 years now. In all that time, I've never captured the kind of evidence that would convince a skeptic. Every time I think I'm close, the phenomenon either stops, shifts, or reveals a mundane explanation I should have seen earlier.

Maybe that's the point. Maybe I'm supposed to see just enough to keep looking, but never enough to prove anything.

Or maybe I'm just another ham operator who noticed an unusual propagation event and let pattern-seeking override common sense.

## What I'm Watching For

I've set the SDR to monitor 7.200-7.215 MHz continuously. If the pattern resumes, it should appear at 7.209 MHz tomorrow at 0612 hours — if the 0.003 increment holds.

The thing is, I don't know what I want to find. Proof it's just a numbers station would be disappointing. Proof it's something else would be terrifying.

Another entry for the log.

Have any of you monitoring HF noticed similar patterns in the 40-meter band? And if something deliberately stops when you're ready to document it — what does that tell you about what it knows?

Stay vigilant.

— JohnD_TN