01Complete system package

Total weight: ~320 g

DUO system diagram

02Objective monitoring tools

Separate monitoring tools are required to objectively verify that jamming is actually affecting the adversary's real video channel.

FPV video scanner

A portable FPV video scanner allows the operator to independently monitor the radio spectrum — the RSSI level (received signal strength indicator: the higher the number, the stronger the signal), active channels, and real-time changes in signal strength — in parallel with DUO operation. When jamming is effective, the scanner detects reduced stability of the adversary's video signal, the appearance of noise, or a sharp drop in reception level — confirming that the interference is actually covering the channel.

If the scanner model can also capture and display the channel image itself (not only RSSI), this provides an even more direct check: the operator sees whether the adversary's image actually breaks up or disappears when DUO jamming is activated — rather than seeing only indirect indicators such as signal level.

TinySA — portable spectrum analyzer

The portable TinySA spectrum analyzer lets you view the actual radio spectrum directly and additionally verify:

• that the frequency to which DUO tuned the jammer VTX actually corresponds to the detected channel;
• detection of spurious (harmonic) components — the transmitter may also emit on frequencies other than the primary one, which can cause DUO to detect this spurious frequency rather than the set one (see “Troubleshooting”);
• confirmation of the actual level of adversary-signal suppression over the air, rather than relying only on the device indication.

03Power specifications

If operation from an onboard supply above 24 V is required, high-quality DC-DC converters must be used.

⚠ Warning Reversed power polarity is unacceptable. Before the first connection, be sure to check the power-source polarity — reversed polarity will damage the device.

⚠ Warning Do not connect a VTX to the device unless an antenna is installed on the video transmitter. Operating a VTX without an antenna will damage the transmitter within a few seconds.

04Operating principle

DUO continuously scans both bands in cycles — 80 channels at 5.8 GHz (4990–5945 MHz), followed by the 3.3 GHz channels in the active table (variant A — 16 channels, 3170–3470 MHz; B — 80 channels, 3060–3840 MHz; C — 101 channels, 3000–4000 MHz; see section 05). If the signal level on a channel exceeds the detection threshold, DUO tunes the corresponding jammer transmitter to the same frequency and activates jamming for the set time, after which scanning continues.

The 128×64 OLED screen displays this process live — separately for each band: a histogram of signal levels across all channels on the left, and a panel showing the current strongest channel and its RSSI on the right. The upper half of the screen is 5.8 GHz; the lower half is 3.3 GHz.

Scanning — no signal of sufficient strength in either band

Signal detected at 5.8 GHz (5800 MHz, 86%)

Signal detected at 3.3 GHz (3310 MHz, 79%)

Scanning performance

The full cycle depends on the table variant 3.3 GHz: ~3.2 s (A) · ~5.5 s (B) · ~6.3 s (C). The 5.8 GHz pass is unchanged; values marked * are calculated (≈36 ms per receiver-path channel 3.3 GHz), to be verified against the firmware.

The response intervals shown are calculated for variant A (16 channels at 3.3 GHz). For variants B and C, the full cycle is longer (see the card above), so all these intervals increase proportionally.

Known cause of incorrect frequency detection

The AKK Alpha 10W VTX (5.8 GHz, included in the package) emits a significant spurious component directly in the main 5.8 GHz band on Band X channels (5050 / 5080 / 5140 MHz) — on some channels, this component is stronger than the primary carrier. This is a property of the specific transmitter model, not of the DUO receiver path: during testing on these channels, the device may detect the spurious-emission frequency instead of the set Band X channel.

05VTX frequency and channel architecture

The channel table is defined in the firmware (channelTable[] / kRx3301FreqTable[]) — DUO searches for signals only at these frequencies, which define the limits of its channel sensitivity.

Three frequency-table variants are provided for the 3.3 GHz jamming channel. Variants A and B correspond to two Kimpok video-transmitter models (16 and 80 channels); variant C — a continuous sweep of the entire 3.0–4.0 GHz band with uniform spacing. Refer specifically to the variant used in your system.

3.3 GHz · Variant A — Kimpok 16ch (spacing 20 MHz)

3.3 GHz · Variant B — Kimpok 80ch (10 bands × 8 channels)

The overall range of the 80ch variant is 3060–3840 MHz. The full channel list is provided for comparison with the markings on the VTX itself.

3.3 GHz · Variant C — continuous sweep 3000–4000 MHz (spacing 10 MHz, 101 frequency)

101 frequencies with uniform 10 MHz spacing cover the entire 3.0–4.0 GHz band without being tied to the channel grid of a specific VTX.

5.8 GHz — 80 channels (AKK Alpha 10W, 10 bands × 8 channels)

Band X — see the warning about spurious emissions above.

06Indication (LED)

The LEDs are visible through the enclosure in the dark. The outer LEDs are green; the inner LEDs are red.

When powered on, the display also briefly shows the device information panel.

Firmware, build date, current THR/JAM, calibration status

07Device placement

The receiving antennas (3.3 and 5.8 GHz) must be installed vertically, unobstructed by the enclosure, propellers, other antennas, or frame elements — this directly affects detection range.

08Startup procedure

Before starting the system, complete five steps in order:

1

Connectors and cables

Check that connectors are secure and that cables and pigtails are intact

→

2

VTX antennas

Make sure the SMA antennas of all VTX units are connected securely

→

3

Cooling

Check that the VTX heat sink and fan are not obstructed

→

4

Power

Connect power — the LEDs flash three times and the information panel appears on the display

→

5

Start scanning

Wait for scanning to begin — the first cycle starts at ~3.2 s (depending on the 3.3 GHz variant)

For details on connecting antennas and VTX units, see “Pre-power-on check.”

09Pinout

Lower connector

* second 3.3 GHz port — not used in the current version

Typical VTX pinout

AKK Alpha 10W · 5.8 GHz

Kimpok 3.3GHz 10W

The pinout is provided for current VTX batches. Before connection, always check the markings on the board or the manufacturer's documentation — the pinout may change without notice.

10Calibration and settings

All control is performed with one button near the lower-right corner of the display.

Control button (S2)

Current values are shown on the display. Settings are retained after power-off.

Calibration screen

First, a countdown before start (remove transmitters from the air), then measurement progress for both bands: the upper half of each bar is the baseline noise level; the lower half is the current pass.

Countdown before start

Calibration progress — pass 3/5

Menu screens

Enter menu — current THR/JAM at bottom

Select value — detection threshold (THRESHOLD)

Select value — jamming duration (JAM TIME)

Save — confirmation of the new value

Exit without changes (40 s without button presses)

Summary after stepping through all parameters

The screen illustrations were generated with the tools/oled_mockup tool from the actual firmware display logic — they are not screen photographs.

11Pre-power-on check

• □Antennas connected to all VTX units
• □SMA connectors tightened
• □Cables undamaged
• □VTX cooling provided
• □Power polarity correct

⚠ Warning Do not connect a VTX to the device unless an antenna is installed on the video transmitter. Operating a VTX without an antenna will damage the transmitter within a few seconds.

Workshop testing

• Use minimum VTX power.
• Provide forced cooling during the test.
• Keep the test drone at least 50 m away.
• Do not conduct prolonged tests without airflow.

If the test drone is too close, the strong signal may cause false triggers in the other band due to harmonics or overloading of internal components.

⚠ Warning A VTX operating at 10W without additional airflow will fail. Minimum power and forced cooling are mandatory for any indoor test.

Combat use / field trials

• Install the system on the frame in the propeller airflow area.
• Make sure fans and heat sinks are not obstructed by mounting elements.
• Set VTX power to maximum (10W) using the button on the VTX enclosure. The VTX retains the power-level setting.

12Testing and expected behavior

Distance to the test drone

Symptom: the device “misses” the channel — it triggers on an adjacent channel instead of the one on which the drone is actually operating.

Cause: the test drone is too close (closer than 30–50 m). The strong signal overloads the receiver — the RSSI level is excessive on several adjacent channels at once, and the device cannot correctly determine the exact channel on which the drone is operating.

Correct procedure:

• test from a distance of 50 meters or more;
• with a clear line of sight between the drone and DUO;
• do not place the test drone directly above the device or right next to the antenna.

At this distance, the signal arrives at a normal level, DUO clearly identifies one channel, and activates targeted jamming on that channel. Under real conditions, an adversary FPV always operates at distances of hundreds of meters or more — this problem does not occur there.

VTX power setting

Cause: DUO does not control VTX power — it controls only the frequency (channel) on which the VTX generates interference. Power is set manually on the VTX itself, once; thereafter, the VTX always operates at that power.

⚠ Heat generation At maximum power — 10–30 W. Do not bench-test at maximum power without airflow — the VTX will overheat and fail within minutes.

General testing rules

• test in an open area without strong reflections (nearby metal hangars and concrete walls distort the results);
• do not operate a VTX without a connected antenna;
• during prolonged testing, monitor the VTX enclosure temperature by hand or with a thermometer;
• bench-test results do not always reproduce field conditions — distance, terrain, and the drone antenna type significantly affect operation.

13Troubleshooting

14Limitations

Electromagnetic compatibility (EMC) and mutual interference

Powerful jammer transmitters may affect nearby equipment — satellite terminals (Starlink), digital video receivers, GPS, and telemetry. The level of impact depends on distance, power, antenna shielding, and the specific mounting configuration on the carrier, so general figures are of little use here.

Recommendation: before continuous operation in a specific configuration, check DUO compatibility with all equipment that will be located nearby on the same platform or position:

• turn on all adjacent equipment (satellite terminal, telemetry/control receivers, GPS) in normal operating mode;
• activate DUO jamming at maximum VTX power in both bands;
• check whether stable communication/lock of adjacent equipment is maintained throughout the entire jamming cycle;
• if failures occur, increase antenna separation and add shielding or filtering to the affected path.

Repeat the test after every significant layout change — a new antenna, a different platform, or new adjacent equipment.

15Overall enclosure dimensions

Length	160 mm
Width	90 mm
Height	25 mm
Mass (without antennas and VTX)	150 g

CAD drawing (click to enlarge)

16Specifications