[!WARNING] Intentional radio jamming is illegal in most countries, including all EU member states and the United States. Use only for authorised testing on equipment you own in a shielded environment. You are solely responsible for compliance with all applicable laws.

Jammer TX transmits interference signals across up to three independently configured frequency ranges simultaneously. Each range is split into 1 MHz segments (hops), and the jammer cycles through them sequentially. All three ranges are active at the same time when enabled.

Range Tabs (Range 1 / Range 2 / Range 3)

Each tab configures one independent frequency range. The three ranges operate together when transmitting.

• Enable range (checkbox): Activates this range. At least one range must be enabled to start.
• Load range: Opens the Freqman frequency manager to load a saved range from the FREQMAN/ directory on the SD card.
• Start / Stop buttons: Set the lower and upper bound of the range directly. Can also be set by loading a range.
• Center / Width buttons: Alternative way to define the range by center frequency and bandwidth.

The combined bandwidth across all enabled ranges must not exceed 80 MHz in total (80 × 1 MHz segments). Exceeding this limit shows an error and prevents transmission from starting.

The hop counter (e.g. 03/12) next to the Type field shows which 1 MHz segment is currently being transmitted and the total number of segments across all active ranges.

Settings

• Type: Signal type generated in each hop segment:

  Option	Description
  Rand FSK	Random FSK noise
  FM tone	FM-modulated tone
  CW sweep	Continuous wave sweep
  Noise	Random amplitude noise
  Sine	Sine wave
  Square	Square wave
  Sawtooth	Sawtooth wave
  Triangle	Triangle wave
  Chirp	Linear frequency chirp
  Gauss	Gaussian noise
  Brute	Broadband noise

• Speed: Modulation rate within each hop segment: 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz

• Hop: Dwell time per 1 MHz segment before moving to the next: Off, 10ms, 50ms, 100ms, 1s, 2s, 5s, 10s — Off disables segment hopping; the jammer stays on each segment indefinitely.

• TX (1–180 seconds): How long the jammer transmits before entering the sleep pause.

• Sleep (0–60 seconds): Pause duration between TX bursts. When Sleep = 0, the TX/pause cycle is disabled entirely and the jammer transmits continuously without stopping. When Sleep > 0, the jammer alternates between TX and pause, with the button label changing to PAUSED during the sleep period.

• Jitter (0–60, unit: /60 seconds): Adds a random LFSR-based offset to the TX and sleep timers to prevent a perfectly periodic duty cycle. 0 = no jitter.

• Gain (0–47): TX gain.

• A (0/1): RF amplifier on/off.

Transmission Parameters

Parameter	Value
Baseband bandwidth	28,000,000 Hz (max TX LPF)
Sampling rate	3,072,000 Hz

Example Configuration (2.4 GHz Wi-Fi)

To target Wi-Fi channels 1, 6, and 11 (2.400–2.483 GHz):

• Range 1: Start 2400000000, Stop 2483000000
• Type: Noise
• Speed: 10 kHz
• Hop: 10ms
• TX: 30 Secs, Sleep: 0 (continuous)
• Jitter: 0

Note that the HackRF's low transmit power (~5–10 dBm) limits effective jamming range to a few metres without an external amplifier.

[!NOTE] Jammer TX has no settings persistence — all settings reset when the app is closed.