Most importantly: I could not find credible reporting that President Trump “arrested” the technology itself, or that a 20-Hz ham-radio system has been established as a population-harassment weapon. What has been reported is considerably more interesting: U.S. authorities secretly acquired a portable pulsed-radio-frequency device for a purchase described as exceeding eight figures, and the Pentagon subsequently tested it because investigators believed it might be relevant to some “Havana Syndrome”/Anomalous Health Incident cases. (CBS News)

STRATEGIC TECHNICAL ASSESSMENT

THE “HAVANA SYNDROME” DEVICE, PULSED RF ENERGY, AND THE CLAIM OF LOW-FREQUENCY RADIO HARASSMENT

Classification: Open-Source Intelligence Assessment
Date: 28 August 2026
Subject: Alleged directed-energy / radio-frequency technology associated with Anomalous Health Incidents (AHIs)

1. Executive Assessment

The most significant verified development is the reported U.S. acquisition in late 2024 of a backpack-sized device capable of producing pulsed radio-frequency energy. Homeland Security Investigations reportedly purchased it using Pentagon funding, with the price described by sources as more than $10 million. The device reportedly contains components of Russian origin, although U.S. authorities have not established publicly who manufactured it or whether it was actually used in Havana Syndrome incidents. The Pentagon has been testing the system. (CBS News)

This is fundamentally different from saying:

“The government has discovered a ham-radio machine that broadcasts 20 Hz and harasses the population.”

That latter proposition is not established by the available evidence.

There are nevertheless several technically important pieces:

1. Pulsed RF energy can interact with biological tissue.
2. Certain RF exposure conditions can produce auditory or other sensations through mechanisms associated with rapidly changing electromagnetic energy.
3. A 2022 U.S. government expert panel concluded that pulsed electromagnetic energy, particularly in the radio-frequency range, plausibly explained some of the core characteristics reported in AHIs. (Ars Technica)
4. The 2023 Intelligence Community assessment subsequently concluded that it was very unlikely/unlikely that a foreign adversary possessed a weapon responsible for the reported incidents, while acknowledging the reality of the symptoms. (The Washington Post)
5. More recent reporting indicates that at least two U.S. intelligence organizations subsequently changed their assessments concerning whether some AHIs could have resulted from a foreign capability. (The Washington Post)

So the current picture is not “proved weapon” versus “imaginary phenomenon.” It is an unresolved technical and intelligence problem with substantially more evidence than existed several years ago.

2. WHAT WAS ACTUALLY PURCHASED?

According to reporting published in January 2026, U.S. authorities secretly obtained a portable, backpack-sized device capable of generating pulsed radio-frequency energy.

The reported acquisition occurred:

Late 2024

during the final weeks of the Biden administration.

The purchaser was reportedly:

Department of Homeland Security — Homeland Security Investigations

with:

Pentagon funding

and the reported expenditure was:

more than eight figures — i.e. greater than $10 million. (CBS News)

The significance of this is considerable.

The U.S. government did not merely purchase an ordinary radio.

It reportedly acquired a specialized system that investigators believed might provide an experimental means of determining whether a technology capable of producing certain reported AHI effects actually exists.

The reported device contains Russian-origin components, but that does not establish Russian manufacture, Russian ownership, or Russian use against Americans. (CBS News)

That distinction is critical.

3. DID TRUMP “ARREST” THE TECHNOLOGY?

No evidence currently establishes this.

The available reporting indicates that the device was acquired before Trump returned to office, during the Biden administration.

The subsequent Trump administration inherited the issue and has been associated with renewed interest in the AHI question.

But “arrested the technology” is not an accurate description of what has been publicly reported.

A more accurate description would be:

The U.S. government acquired a suspected pulsed-RF device, secured it for examination, and subjected it to military/intelligence testing.

The distinction matters because there is a huge difference between:

A. confiscating a machine

and

B. proving that the machine caused Havana Syndrome

and

C. proving who built the machine

and

D. proving that the machine was operationally used against particular people.

Those are four separate intelligence questions.

4. WHAT IS “HAVANA SYNDROME”?

“Havana Syndrome” is the informal name given to a collection of unusual health incidents first publicly associated with U.S. personnel in Havana beginning in 2016.

The government increasingly uses:

Anomalous Health Incidents — AHI

instead.

Reported symptoms have included:

• unusual sounds or sensations
• pressure or pain
• dizziness
• headaches
• nausea
• balance problems
• visual disturbances
• tinnitus
• cognitive difficulties
• sleep disturbances
• neurological symptoms

The existence of people experiencing these symptoms is not seriously in dispute.

The controversy concerns:

CAUSE.

5. THE CENTRAL TECHNICAL HYPOTHESIS

One important hypothesis involves:

Pulsed radio-frequency electromagnetic energy

This is fundamentally different from ordinary continuous radio transmission.

A transmitter can produce electromagnetic energy in pulses rather than as a continuous signal.

Conceptually:

Continuous RF

████████████████████████████

versus:

Pulsed RF

██    ██    ██    ██    ██

The important variable isn’t simply the radio frequency.

A proper analysis requires examining:

• carrier frequency
• pulse duration
• pulse repetition frequency
• peak power
• average power
• waveform
• modulation
• antenna characteristics
• beam geometry
• distance
• exposure duration
• reflections
• shielding
• biological coupling

This is why describing the alleged system merely as a “20-Hz radio” is technically inadequate.

6. THE 20-HZ CLAIM

This is where an important distinction must be made.

20 Hz is not normally what people mean by a ham-radio frequency.

20 Hz means:

20 cycles per second.

That is extraordinarily low frequency compared with conventional amateur-radio transmissions.

The amateur-radio spectrum operates primarily at much higher frequencies, ranging from kilohertz through megahertz and into gigahertz bands.

A system could, however, theoretically have:

RF carrier + low-frequency modulation

For example, conceptually:

          RF carrier
~~~~~~~~~~~~~ ~~~~~~~~~~~~~~
      modulation envelope
    /¯¯\      /¯¯\
___/    \____/    \____

In such a system, someone might describe the modulation or pulse-repetition component as approximately 20 Hz while the electromagnetic carrier itself is vastly higher in frequency.

Therefore:

“20-Hz radio” ≠ automatically “20-Hz electromagnetic weapon.”

The terminology needs to be examined carefully.

7. WHY LOW-FREQUENCY MODULATION COULD MATTER

A low-frequency modulation rate can be imposed upon a high-frequency electromagnetic carrier.

For example, conceptually:

Carrier: RF
Modulation: 20 Hz

That does not mean the human body is being exposed to ordinary 20-Hz radio in the conventional sense.

Instead:

The RF energy is structured according to a slower temporal pattern.

This distinction is especially important when discussing pulsed electromagnetic effects.

The 2022 expert panel specifically identified pulsed electromagnetic energy, particularly RF energy, as a plausible mechanism for some characteristics of the reported AHIs. (Ars Technica)

8. THE “FREY EFFECT” CONNECTION

One relevant scientific phenomenon is sometimes called the:

Microwave auditory effect

or

Frey effect

Under certain circumstances, pulsed electromagnetic energy can produce auditory perceptions without conventional sound being transmitted through the air in the ordinary way.

This phenomenon has been studied experimentally.

That does not, however, establish that Havana Syndrome was caused by such a mechanism.

It establishes only that:

Electromagnetic energy can under certain circumstances produce biological/auditory effects.

The question for investigators is whether a particular device can produce the required exposure conditions at meaningful distances and whether those conditions correspond to the actual incidents.

9. WHY THE $10+ MILLION PURCHASE IS SIGNIFICANT

The reported price is one of the most intriguing aspects.

A conventional amateur-radio transmitter does not require anything remotely approaching this expenditure.

Therefore, if the reporting is accurate, the acquisition was not simply:

“Someone bought a powerful ham radio.”

It was reportedly an intelligence/defense acquisition involving specialized equipment.

Possible reasons for such an acquisition could include:

A. Forensic examination

Determine:

• what components are inside
• what frequencies it can generate
• what waveform it produces
• what power levels are achievable

B. Reproduction testing

Determine whether researchers can reproduce effects reported by AHI victims.

C. Threat assessment

Determine whether similar equipment could represent a foreign intelligence or security capability.

D. Countermeasure development

Determine how such a system might be detected, blocked, localized, or shielded.

E. Attribution

Determine whether components correspond to known foreign weapons research.

None of those possibilities by itself establishes that the device was actually used against the public.

10. RUSSIAN COMPONENTS

The reporting that the device contains Russian-origin components is important but easy to overinterpret.

There are several possibilities:

Possibility 1

A Russian government system.

Possibility 2

A system developed by a Russian defense contractor.

Possibility 3

A foreign system incorporating commercially available Russian components.

Possibility 4

A system assembled elsewhere using Russian-origin components.

Possibility 5

A deliberately constructed intelligence deception.

Therefore:

Russian component ≠ Russian weapon.

The public reporting does not establish the chain of custody sufficiently to make that leap. (CBS News)

11. THE 2022 EXPERT PANEL

This is one of the most important pieces of the historical record.

A U.S. government-convened panel of experts concluded in 2022 that:

pulsed electromagnetic energy, particularly in the RF range, plausibly explains the core characteristics of some reported incidents.

The panel also noted that potentially relevant sources could be sufficiently concealable and have moderate power requirements. (The Guardian)

But:

“Plausible” does not mean “proven.”

The panel did not establish:

• who operated such a device
• where it was located
• whether Russia operated one
• whether a particular incident was an attack
• whether all AHIs had a common cause

This is an essential distinction.

12. THE 2023 INTELLIGENCE ASSESSMENT

In 2023, the broader U.S. Intelligence Community reached a substantially more skeptical conclusion.

Five agencies reportedly judged it very unlikely and two judged it unlikely that a foreign adversary possessed a weapon responsible for the reported incidents. (The Washington Post)

The assessment covered a very large number of reported cases.

AP reported that investigators examined approximately:

1,500 cases in 96 countries. (AP News)

The intelligence assessment did not mean:

“Nobody was sick.”

Instead, it meant that the available evidence did not support the conclusion that a foreign adversary was responsible.

That is an important difference.

13. THE INTELLIGENCE POSITION THEN CHANGED

The newest reporting complicates the story considerably.

According to reporting in February 2026, two U.S. intelligence organizations changed their assessment after new reporting concerning foreign capabilities.

The organizations were reported to include:

• National Security Agency
• U.S. Army National Ground Intelligence Center

They reportedly concluded that a foreign actor having a capability capable of producing biological effects consistent with some AHIs was more plausible than previously assessed. (The Washington Post)

At the same time:

other agencies continued to reject the foreign-adversary explanation as the most likely explanation.

Therefore there is now an intelligence disagreement.

That is substantially more interesting than the simplistic narrative that:

“The government proved Havana Syndrome.”

It hasn’t.

14. THE NORWEGIAN EXPERIMENT

A particularly extraordinary development reported in 2026 concerns a Norwegian government scientist.

According to reporting, the researcher constructed and secretly tested a microwave-based device on himself in an attempt to challenge the hypothesis that directed-energy technology could produce Havana-Syndrome-like effects.

The experiment reportedly produced symptoms including:

• dizziness
• cognitive problems
• other symptoms resembling those reported in AHIs.

U.S. officials subsequently examined the matter, including Pentagon personnel. (The Washington Post)

This is important because it moves the discussion away from:

“Could physics possibly do this?”

toward:

“Can a real engineered system produce relevant biological effects under controlled conditions?”

However, even this experiment does not prove that foreign intelligence agencies attacked American personnel.

15. WHAT WOULD A REAL INVESTIGATION HAVE TO ESTABLISH?

A serious investigation would need to establish a complete causal chain:

DEVICE
   ↓
RF GENERATION
   ↓
WAVEFORM
   ↓
ANTENNA
   ↓
PROPAGATION
   ↓
TARGET EXPOSURE
   ↓
BIOLOGICAL INTERACTION
   ↓
OBSERVED SYMPTOMS

And separately:

DEVICE
   ↓
OWNERSHIP
   ↓
OPERATOR
   ↓
LOCATION
   ↓
MOTIVE
   ↓
TARGETING EVENT

Both chains have to be established.

A device capable of producing an effect is not proof that it produced a particular historical incident.

16. THE “POPULATION HARASSMENT” CLAIM

This needs particularly careful treatment.

There is no reliable public evidence establishing that a 20-Hz ham-radio system is currently being used to systematically harass an entire population.

That does not mean every individual report should automatically be dismissed.

It means that a population-level allegation requires considerably stronger evidence.

For example:

Required evidence

• synchronized measurements at multiple locations
• calibrated RF sensors
• frequency-spectrum recordings
• directional measurements
• temporal correlation
• source localization
• independent laboratories
• repeatable exposure conditions
• environmental controls
• medical assessment

Without these, subjective reports alone cannot determine whether a particular RF source is responsible.

17. WHAT WOULD A REAL “RADIO HARASSMENT” SIGNATURE LOOK LIKE?

An actual RF investigation would attempt to identify:

Frequency

Bandwidth

Pulse repetition frequency

Pulse width

Peak field strength

Average field strength

Polarization

Direction of arrival

Duty cycle

Time of occurrence

Geographical distribution

For example:

TIME
│
├── 02:11:04
├── 02:11:05
├── 02:11:06
│
└───────────────→
RF SPECTRUM
        │
        │       ███
        │       ███
────────┼───────███────────
        │
        └──────────────────
             FREQUENCY

If multiple independent receivers detected exactly the same anomalous signal at the same time, investigators could begin establishing an electromagnetic event.

18. WHY “HAM RADIO” IS A PROBLEMATIC DESCRIPTION

Amateur radio equipment is extraordinarily diverse.

A ham-radio operator may legally transmit over numerous designated bands depending on jurisdiction and license.

But that does not make:

“ham radio”

synonymous with:

“directed-energy weapon.”

A specialized RF device could potentially use components derived from technologies also found in ordinary radio equipment.

That is analogous to saying:

“A computer uses semiconductor chips, therefore a military supercomputer is just a PC.”

The underlying engineering disciplines overlap, but the systems can be radically different.

19. WHAT THE PENTAGON IS PRESUMABLY INTERESTED IN

If the reporting about the acquired device is accurate, the military value of examining it would extend well beyond Havana Syndrome.

A sophisticated pulsed-RF system could potentially be studied for:

Electronic warfare

Disrupting or damaging electronic systems.

Intelligence

Understanding foreign RF technologies.

Countermeasures

Detecting unusual electromagnetic emissions.

Force protection

Protecting personnel from electromagnetic exposure.

Medical research

Understanding possible biological effects.

Attribution

Identifying technological fingerprints associated with particular manufacturers or countries.

20. THE MOST IMPORTANT UNANSWERED QUESTION

The most important question isn’t:

“Does RF energy exist?”

It obviously does.

Nor is it:

“Can electromagnetic energy affect biological systems?”

Under appropriate circumstances, it can.

The crucial intelligence question is:

Did a particular actor deliberately deploy a particular technology against particular people?

That requires evidence connecting:

weapon → location → operator → target → exposure → effect.

Publicly available information does not yet establish that complete chain.

21. CURRENT EVIDENCE MATRIX

22. STRATEGIC CONCLUSION

The genuinely important story is more nuanced—and arguably more consequential—than the viral version.

The U.S. government reportedly spent more than $10 million obtaining a compact pulsed-RF device that investigators considered sufficiently interesting to justify clandestine acquisition and Pentagon examination. (CBS News)

At the same time, the U.S. government’s own assessments have historically disagreed sharply:

2020/2022 expert work:
Pulsed RF energy is a plausible explanation for some reported phenomena. (The Guardian)

2023 Intelligence Community assessment:
A foreign adversary was unlikely to be responsible. (The Washington Post)

2025/2026 developments:
New reporting caused at least two intelligence organizations to reassess the plausibility of a foreign capability, while other agencies remained skeptical. (The Washington Post)

2026 Norwegian experiment:
A government researcher reportedly reproduced concerning symptoms during an experiment involving a microwave device, prompting further U.S. examination—but this still does not establish the historical cause of Havana Syndrome. (The Washington Post)

Therefore, the strongest defensible conclusion as of 28 August 2026 is:

There is credible evidence that specialized pulsed-RF technology capable of producing biologically relevant electromagnetic exposure is a real subject of U.S. government investigation. There is also credible reporting that the U.S. acquired a multimillion-dollar device for testing. But there is not publicly established evidence that a “20-Hz ham-radio machine” is conducting population-wide harassment, nor evidence that President Trump has literally “arrested” such a technology.

The next major evidentiary breakthrough would be laboratory characterization of the seized device, controlled biological testing, electromagnetic measurements, and—most importantly—evidence connecting a particular device to a particular historical incident.

That is the point at which the Havana Syndrome controversy would move from a disputed intelligence hypothesis into a demonstrable technological case.