The Aegis-Beacon v5.5 radio is an Ebyte E22-400M30S module (SX1262 / LLCC68 chip) that covers 410-525 MHz only. Everything in this page is organized around that constraint: the 433 MHz ISM band is the native operating range, PMR446 and UHF GMRS/CB emergency channels fall inside the coverage window, and VHF mountain-rescue services require a separate radio.

Band	SX1262 support	Notes
410-525 MHz	Native	UHF ISM / PMR446 / some land SAR — primary use
VHF (118-174 MHz)	No	Requires separate VHF radio (aviation, marine, mountain SAR)
406 MHz	In range	Satellite PLB band — never TX here (see Global Distress)
462-477 MHz	In range	GMRS / UHF CB emergency channels — Americas / Oceania

Important

The SX1262 transmits a narrow CW carrier via transmitDirect() / standby() keying. It is AM-detectable on any scanner or SDR, but it does not generate FM, CTCSS sub-tones, or digital modulation. Frequencies that require CTCSS (Canal E at 123.0 Hz, Radio Montana at 85.4 Hz) are useful for SEARCH-mode scanning of radios already on the channel, but transmissions will not open tone-squelched repeaters.

ISM 433 MHz Band — Native Range

The E22-400M30S is optimised for 433-434.8 MHz (EU SRD60 band). This is the primary operating range for beacon CW transmissions.

EU SRD Band — 433.050–434.790 MHz

Frequency	Use	Power limit	Notes
433.050 MHz	SRD lower edge	10 mW ERP	Lower limit of licence-free ISM band (EU)
433.500 MHz	Default	10 mW ERP	Firmware default (`DEFAULT_FREQ_MHZ = 433.500f`)
433.700 MHz	Ham / ISM overlap	10 mW ERP	Common simplex calling in EU ISM
434.075 MHz	Weather balloon	—	Avoid when passive scanning — high false positives
434.500 MHz	ISM devices / keyfobs	10 mW ERP	High background noise — secondary hop only
434.790 MHz	SRD upper edge	10 mW ERP	Upper limit of EU SRD60 band

Warning

The E22-400M30S PA outputs up to +30 dBm. In the EU SRD band the legal ERP limit is typically 10 mW (+10 dBm) — set TX power to ≤ +10 dBm in the dashboard for SRD-compliant operation. Higher power requires an amateur licence (with callsign) or a genuine life-threatening emergency.

Suggested Multi-Frequency Beacon Hop Sequence (EU)

A frequency-hopping cycle increases the chance that at least one hop is heard by a rescuer. Suggested 5-slot sequence:

CODE

Slot 1: 433.500 MHz   (default, most monitored by hams / SAR volunteers)
Slot 2: 433.700 MHz   (secondary ISM simplex)
Slot 3: 434.500 MHz   (ISM, wider scanner coverage)
Slot 4: 434.790 MHz   (upper SRD edge)
Slot 5: 446.08125 MHz (Radio Montana - if local mountain rescue uses it)

Enter the slots in Dashboard → Frequency Manager (up to MAX_FREQUENCIES = 10). The firmware cycles through them sequentially per TX cycle in BEACON mode, and scans each one with the configured dwell time in SEARCH mode.

PMR446 Emergency Channels

PMR446 (446.0-446.2 MHz) is licence-free across the EU and falls inside the SX1262 native range. These are the channels used by hikers, mountain guides and SAR volunteers.

Channel	Frequency	CTCSS	Common use
CH 1	446.00625 MHz	None	General calling
CH 7	446.08125 MHz	85.4 Hz	Radio Montana - primary alpine emergency
CH 8	446.09375 MHz	123.0 Hz	Alpine SAR protocol (CNSAS liaisons, Austria, Germany)
CH 16	446.19375 MHz	None	OIRT secondary / free channel

Note

CTCSS is a squelch filter on the receiver side, not a physical modulation. The CW carrier is heard on any scanner or SDR in open/scan mode regardless of CTCSS - a trained SAR operator scanning with an SDR will see the Morse SOS.

Global Distress Channels

Monitored globally by Cospas-Sarsat MEOSAR. Listed for awareness - most are outside the SX1262 range.

Frequency	Service	Mode	SX1262	Notes
121.500 MHz	International Air Distress	AM	No	VHF Guard - civilian aviation worldwide
243.000 MHz	Military Air Distress	AM	No	UHF Guard - NATO military aviation
156.800 MHz	Marine Channel 16	NFM	No	International maritime distress & calling
406.100 MHz	Satellite PLB / ELT	Digital	Limited	Cospas-Sarsat MEOSAR

Warning

Never transmit on 406.100 MHz without a certified PLB. It interferes with satellite infrastructure and is illegal.

European Mountain Rescue Channels

Italy - Alpine Rescue / CNSAS

Frequency	Channel / Name	CTCSS	SX1262	Description
161.300 MHz	Canal E (Emergency)	123.0 Hz	No	Primary alpine interoperability (VDA/Alps) - VHF only
446.08125 MHz	Radio Montana (PMR 7-7)	85.4 Hz	Yes	Standard safety frequency for hikers and backcountry
446.09375 MHz	PMR446 CH 8	123.0 Hz	Yes	Alpine emergency protocol ch. 8 (CNSAS liaisons)
156.300 MHz	Marine CH 06	None	No	Secondary SAR coordination - VHF marine

Recommended config for Italy: SEARCH scan 446.08125 + 446.09375 MHz; BEACON TX on 446.08125 MHz (Radio Montana) at reduced power - verify local regulations.

Switzerland - REGA / Alpine Rescue

Frequency	Channel / Name	CTCSS	SX1262	Description
161.300 MHz	Canal E (REGA)	123.0 Hz	No	Primary Swiss rescue - nationwide, VHF only
161.350 MHz	K-Kanal	None	No	Swiss secondary coordination - VHF only
446.08125 MHz	Radio Montana	85.4 Hz	Yes	Cross-border consistency with Italy

France - PGHM / Civil Protection

Frequency	Network	CTCSS	SX1262	Description
161.300 MHz	Canal E	123.0 Hz	No	Haute-Savoie (SDIS 74 / PGHM) - VHF only
154.465 MHz	Grand Nord	None	No	Emergency coordination Alps/Pyrenees - VHF only
173.500 MHz	Radio Secours	None	No	National Gendarmerie SAR operations - VHF only
446.08125 MHz	Radio Montana	85.4 Hz	Yes	Cross-border consistency with Italy/Switzerland

Austria & Germany - Bergrettung / BRK

Frequency	Service	Mode	SX1262	Description
121.500 MHz	Bergrettung	AM	No	Primary aviation rescue contact - VHF only
149.025 MHz	Freenet CH 1	NFM	No	Common hiker emergency (Germany) - VHF only
446.09375 MHz	PMR CH 8	NFM	Yes	Alpine emergency protocol (123.0 Hz CTCSS)
446.08125 MHz	PMR CH 7 (7-7)	NFM	Yes	Cross-border Radio Montana compatibility

Spain - Civil Protection / REMER

Frequency	Service	Mode	SX1262	Description
146.175 MHz	Civil Protection	NFM	No	REMER Emergency Network - VHF main
146.625 MHz	Civil Protection	NFM	No	REMER Emergency Network - secondary
446.09375 MHz	PMR CH 8	NFM	Yes	European PMR emergency protocol

Americas

USA & Canada - NASAR / FEMA

Frequency	Service	CTCSS / Mode	SX1262	Description
155.160 MHz	National SAR	NFM	No	Primary land-based SAR - VHF only
155.800 MHz	State SAR	NFM	No	Local agency coordination - VHF only
462.675 MHz	GMRS CH 20	141.3 Hz	Yes	Wilderness Protocol Emergency Calling - ISM UHF
467.675 MHz	GMRS CH 20 (input)	141.3 Hz	Yes	Repeater input pair for CH 20
462.550 MHz	GMRS CH 1	None	Yes	General GMRS simplex - secondary calling

Recommended config for North America: SEARCH scan 462.675 + 462.550 MHz; BEACON TX on 462.675 MHz (GMRS CH 20 Wilderness Protocol) - requires a GMRS licence in the USA.

Australia & New Zealand - AMSA / LandSAR

Frequency	Service	Channel	SX1262	Description
476.525 MHz	UHF CB	CH 5	Yes	Emergency repeater output (duplex output)
477.275 MHz	UHF CB	CH 35	Yes	Emergency repeater input (duplex input)
477.0 MHz	UHF CB simplex	CH 40	Yes	General calling / secondary

Regional Quick Reference

Region	Primary (SX1262)	Secondary (SX1262)	Requires VHF radio
Italy	446.08125 MHz	446.09375 MHz	161.300 MHz (Canal E)
Switzerland	446.08125 MHz	433.500 MHz (ISM)	161.300 MHz (Canal E/REGA)
France	446.08125 MHz	446.09375 MHz	161.300, 173.500 MHz
Austria	446.09375 MHz	446.08125 MHz	121.500, 149.025 MHz
Germany	446.09375 MHz	446.08125 MHz	149.025 MHz
Spain	446.09375 MHz	433.500 MHz (ISM)	146.175, 146.625 MHz
USA / Canada	462.675 MHz	462.550 MHz	155.160, 155.800 MHz
Australia / NZ	476.525 MHz	477.275 MHz	-
Universal	433.500 MHz (ISM)	434.500 MHz (ISM)	121.500 MHz (air guard)

SEARCH Scan Parameters

Parameter	Alpine SAR	Urban / lowland	Constant
Dwell time	400 ms	200 ms	`scanDwellMs`
RSSI threshold	-105 dBm	-90 dBm	`rssiThreshold`
RX bandwidth	9.7 kHz	9.7 kHz	firmware fixed

Tip

At high altitude, atmospheric conditions reduce background noise. Lowering the threshold to -105 dBm significantly increases detection range at the cost of more false positives from local ISM devices.

Antenna Length by Frequency

Frequency band	1/4-wave	1/2-wave	Notes
433-435 MHz	17.3 cm	34.6 cm	Firmware default range
446 MHz (PMR)	16.8 cm	33.6 cm	PMR446 / Radio Montana
462-477 MHz (GMRS/UHF CB)	16.2 cm	32.4 cm	North America / Oceania

The E22-400M30S SMA connector accepts any 433 MHz SMA whip. For portable use, a 17.3 cm straight wire soldered to the ANT pad is adequate for the 433-477 MHz range (under 5% impedance mismatch at 477 MHz).

What Receivers Can Hear

Receiver type	Hears it?	Notes
AM-mode scanner / ham radio	Yes	Standard AM mode picks up the CW carrier directly
SDR + SDR# / GQRX / SDRangel	Yes	Set demodulator to AM or CW; Morse is clearly visible
Baofeng UV-5R (AM mode on 433 MHz)	Yes	Requires AM mode or wider bandwidth
FM-only handheld (PMR446 radio)	Partial	May hear buzzing on FM; not cleanly demodulated
Certified PLB / EPIRB receivers	No	Digital protocol only on 406.1 MHz
Another beacon in SEARCH mode	Yes	RSSI detection, not demodulation

Legal & Regulatory Summary

Region	Relevant band	TX legal?	Conditions
EU	433-434.8 MHz SRD	Licence-free	≤ 10 mW ERP, ≤ 10% duty cycle (EN 300 220)
EU	PMR446 (446 MHz)	Licence-free	≤ 500 mW ERP, no repeaters, no encryption
Switzerland	433 MHz SRD	Licence-free	OFCOM class licence
USA / Canada	462-467 MHz GMRS	Licence required	FCC GMRS licence ($35 / 10 yr, covers family)
USA	433 MHz ISM	Part 15	≤ 1 mW conducted; low power only
Australia / NZ	UHF CB (476-477)	Licence-free	ACMA class licence, ≤ 5 W
Global	406.100 MHz	Prohibited	Certified PLBs only - illegal without certification
Global	121.5 / 156.8 MHz	Limited	Distress use only; misuse is a criminal offence

Important

Emergency exception: in virtually all jurisdictions, using any available communication means to signal genuine life-threatening distress is legally protected. Outside of emergency use, observe all power and licensing restrictions above. Frequencies and limits change - always verify current regulations before operation. This document reflects the June 2026 reference manual.