Disclaimer: The following analysis is based on empirical observation of HF traffic and does not represent an official specification. The identification of protocol messages and roles is a technical hypothesis intended for research purposes.
This post examines what appears to be a custom HF adaptation of the WireGuard VPN protocol [1], a streamlined UDP-native protocol designed for high-performance secure tunneling. While the examined protocol shares characteristics with both MESH and VPN architectures, I have opted for the latter definition. This is because an HF implementation of a mesh protocol is better suited for tactical (field-deployed) theaters rather than the consolidated, fixed-site network observed in this case.
I have used the term "WireGuard-like" in the title because the observed packet structures diverge from standard specifications; nevertheless, protocol-specific signatures suggest a proprietary implementation tailored for transmission over HF links. For convenience, the term "WireGuard" (WG) will be used hereafter to refer to this specific implementation, its framing characteristics, and the field designations identified here.This analysis also serves as a continuation of the work initiated in [2] [3]; readers are encouraged to refer to those previous posts for background on the operational scenario.
As established in the aforementioned posts, the bulk of the previous captures consists of intermittent 2G-ALE (MS-141A) handshakes between Node 101 (caller) and Node 102 (called). Sometimes handshakes are followed by short MS-110A bursts, carrying encapsulated STANAG-5066 UDP payloads of 16 and 32 bytes. However, a few days ago (February 19), while occasionally monitoring 20779.5 kHz (1), sustained async MS-110A transmissions were recorded, characterized by prolonged data exchanges specifically between nodes 101 and 102 (Figure 1). Unlike the sporadic heartbeats/pings observed earlier, these emissions suggest the transfer of larger, continuous data blocks. My friend Kosmod kindly shared his recordings with me.
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| Fig. 1: Waterfall display showing continuous MS-110A bursts on 20779.5 kHz, indicating an active data session between ALE nodes 101 and 102 |
1. Bitstream Analysis
The MS-110A demodulated bitstreams exhibit the expected 8N1 asynchronous framing format, an example is shown in Figure 2. This format ensures that even if the radio link drops or fades momentarily, the serial framing allows the hardware to re-sync at the very next byte, rather than losing an entire synchronous frame.
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| Fig. 2: MS-110A 8N1 asynchronous pattern |
After stripping the asynchronous start/stop bits, the underlying STANAG-5066 frames are identified via their 0x90EB sync sequence. These frames encapsulate IP traffic within U_PDUs (Unreliable/Unacknowledged PDUs), facilitating data exchange between nodes 011.020.100.101 and 011.020.100.102 (Figure 3a). The U_PDU payloads were subsequently extracted and reassembled, revealing IP/UDP datagrams routed between 192.168.101.15 and 192.168.102.15. Analysis of the reassembled UDP payloads identified a consistent 0x04 initial value, corresponding to WireGuard Type 4 Transport Data packets (2). This protocol identification was further validated by the Wireshark dissector (Figure 3b).
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| Fig. 3: Example of protocol decapsulation using STANAG-5066 (3a) and Wireshark dissectors (3b) |
Figures 3a/3b highlights some interesting elements:
1. Cross-Layer Addressing: source and destination IP addresses are correlated with the ALE and STANAG-5066 node IDs. This mapping confirms a consistent logical-to-physical addressing scheme, verifying the identity of the transceiving stations across the radio link:ALE address: 101 -> STANAG-5066 address: 011.020.100.101 -> LAN IP address: 192.168.101.15
ALE address: 102 -> STANAG-5066 address: 011.020.100.102 -> LAN IP address: 192.168.102.15
2. Transport Layer Optimization: the capture reveals the implementation of UDP (User Datagram Protocol). This choice is mirrored at the data-link layer by the use of STANAG-5066 Non-ARQ data transfer.
3. Encapsulated Tunneling: further dissection of the UDP payload identifies the use of an HF implementation of WireGuard VPN Protocol, indicating that the session employs a modern, high-performance encryption to secure the traffic.
2. Proposed Protocol Analysis
(All field designations are my own and are used for convenience of presentation)
The following section provides the UDP payloads analysis of the data transfer session illustrated in Figure 4.
The following section provides the UDP payloads analysis of the data transfer session illustrated in Figure 4.
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| Fig. 4: spectral time-frequency analysis |
For reference, the following workflow was utilized for signal processing and analysis:
- MS-110A demodulation and asynchronous start/stop bit stripping
- STANAG-5066 protocol dissection
- Extraction and reassembly of segmented U_PDUs (Unreliable Data Protocol Units)
- Wireshark IP packet dissection
- Hexadecimal forensic analysis of the extracted UDP payloads
The session commences with the standard MS-141A 2G-ALE handshake between Node 101 (caller) and Node 102 (called) which are followed by 3 WG bursts.
WG1 burst:
Internet Protocol Version 4, Src: 192.168.101.15, Dst: 192.168.102.15
User Datagram Protocol, Src Port: 55504, Dst Port: 2753
UDP payload (32 bytes): 002000020003cbf6c0a8650f00000def699713f500010000c0a8660f0000064d
This 32-byte pyload is the first packet of a new session, it serves as the "Announcement" or "Master Synchronization" Type 2 Message . In a high-latency, low-bandwidth environment like HF, you cannot afford the back-and-forth of a standard TCP-style or WireGuard handshake. Instead, the sender "pushes" the entire connection state in this single 32-byte burst.
WG2 burst:
Internet Protocol Version 4, Src: 192.168.102.15, Dst: 192.168.101.15
User Datagram Protocol, Src Port: 54107, Dst Port: 2754
UDP payload (28 bytes): 001c00010600a36dc0a8660f0001000ec0a8650f00000def00010002
Internet Protocol Version 4, Src: 192.168.102.15, Dst: 192.168.101.15
User Datagram Protocol, Src Port: 54107, Dst Port: 2754
UDP payload (28 bytes): 001c00010600a36dc0a8660f0001000ec0a8650f00000def00010002
This 28-byte payload serves as the Synchronized Acknowledgement (ACK) Type 1 Message. It confirms that the receiver has accepted the session parameters (Session ID and Clock) proposed in the initial 32-byte WG1 burst.
WG3 burst: The WG3 burst consists of two parts:
WG3_1 part:
WG3_1 part:
Internet Protocol Version 4, Src: 192.168.101.15, Dst: 192.168.102.15
User Datagram Protocol, Src Port: 55504, Dst Port: 2753
User Datagram Protocol, Src Port: 55504, Dst Port: 2753
UDP payload (32 bytes): 002000020003cbf6c0a8650f00000def699713f500010000c0a8660f0000064d
In this capture, the third payload seems to complete the MS-141A ALE Three-Way Handshake paradigm, transitioning the link from the "Linking" state to the "Data Traffic" state. Interestingly, the hex for this 3rd packet is identical to the 1st packet. In HF protocols, this usually indicates a re-transmission or a State Enforcement frame to ensure the receiver definitely has the Master Context before the data burst begins.
WG3_2 part:
Internet Protocol Version 4, Src: 192.168.101.15, Dst: 192.168.102.15
User Datagram Protocol, Src Port: 55504, Dst Port: 2753
WireGuard Protocol
Type: Transport Data (4)
Reserved: 000000
Receiver: 0x9ee70200
Counter: 17225424150020335808
Encrypted Packet
User Datagram Protocol, Src Port: 55504, Dst Port: 2753
WireGuard Protocol
Type: Transport Data (4)
Reserved: 000000
Receiver: 0x9ee70200
Counter: 17225424150020335808
Encrypted Packet
Examination of the UDP payload hexdump reveals a consistent 0x04000000 initial sequence , i.e., a fingerprint of standard-WireGuard Transport Data Type 4 Message.
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| Fig. 5: hexdump of WG3_2 UDP payload |
The structural composition of the header is detailed below:
The 16-byte Authentication Tag is always the last 16 bytes appended at the end of the encrypted payload. This tag is the result of the Poly1305 algorithm ChaCha20-Poly1305 for Authenticated Encryption with Associated Data (AEAD).
Note that while the Receiver Index is stored in Little-Endian (WireGuard standard), the Embedded IP (C0 A8...) is stored in Big-Endian (Network Byte Order). This "hybrid" endianness is an indicator of a custom wrapper being used to bridge standard networking with the WireGuard protocol.
Note that while the Receiver Index is stored in Little-Endian (WireGuard standard), the Embedded IP (C0 A8...) is stored in Big-Endian (Network Byte Order). This "hybrid" endianness is an indicator of a custom wrapper being used to bridge standard networking with the WireGuard protocol.
In a standard WireGuard implementation, the Nonce (bytes 08-15) is usually just a monotonic counter starting from zero.
However, this specific capture shows interesting points:
1. Identity Injection: by placing 192.168.101.15 (the sender's internal IP) directly into the first 4 bytes of the Nonce, the receiver can verify the source of the packet at the cryptographic layer before even attempting to decrypt the inner payload.
2. Timestamp Alignment: the following 4 bytes (00 00 0d ef) ensure the packet is unique and in sequence.
3. The "Double Match": notice this is an exact match to the 32-byte Master Sync packet analyzed in WG_1 burst. This confirms that the first data packet in a session "inherits" the sequence number and identity used during the handshake to prevent any startup delay on the HF link.
Below the complete packet flow summary.
In this HF-optimized environment, the 32-byte Master Sync (WG1 burst) functions as a "state-push" mechanism, forcefully synchronizing the absolute Unix Epoch and session identity to satisfy WireGuard's anti-replay requirements in a single burst. The subsequent 28-byte ACK (WG2 burst) confirms bidirectional reachability and IP binding, while the final 32-byte State Lock (WG3_1 part) ensures the receiver is fully primed despite potential HF fading or ALE tuning delays. This robust "handshake-less" initiation minimizes airtime while establishing the necessary cryptographic context for the immediate transmission of WireGuard Type 4 Data packets.
Another significant capture reveals the existence of a 16-byte Type 3 Message, which in this context likely functions as a Status/Keep-Alive announcement. Notice that this Type 3 control message is transmitted immediately following the 2G-ALE (MS-141A) handshake, without an instant follow-up data burst, thereby marking the transition from link establishment to tunnel maintenance. Figure 6 displays the transition between the physical (2G-ALE) and logical (WG message) layers.
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| Fig. 6 : transition between the physical (2G-ALE) and logical (Type 3 Message) layers |
The following table provides the proposed structure of the Type 3 message:
Internet Protocol Version 4, Src: 192.168.101.15, Dst: 192.168.102.15
User Datagram Protocol, Src Port: 56503, Dst Port: 2753
UDP payload (16 bytes): 0010000306001056c0a8650f0000059d
Internet Protocol Version 4, Src: 192.168.101.15, Dst: 192.168.102.15
User Datagram Protocol, Src Port: 56503, Dst Port: 2753
UDP payload (16 bytes): 0010000306001056c0a8650f0000059d
While Type 1 & 2 messages handle acknowledgments between peers, shorter 16-byte Type 3 messages likely serve as heartbeat signals, periodically announcing the presence of the 192.168.101.15 node to the network.
The immediate transmission of the Type 3 message after the 2G-ALE handshake serves as a bridge between the physical layer (radio synchronization) and the logical layer (tunnel persistence). This ensures that the UDP session is active before the bulk transport of Type 4 encrypted data begins. As seen in previous sequences, the ALE → WG transition is the "acid test" confirming that the system utilizes ALE merely as a pathfinder before immediately handing over control to the tunneling protocol.
The immediate transmission of the Type 3 message after the 2G-ALE handshake serves as a bridge between the physical layer (radio synchronization) and the logical layer (tunnel persistence). This ensures that the UDP session is active before the bulk transport of Type 4 encrypted data begins. As seen in previous sequences, the ALE → WG transition is the "acid test" confirming that the system utilizes ALE merely as a pathfinder before immediately handing over control to the tunneling protocol.
2.1. Functional Parallelism with MS-141A Sounding
Critical observation of the traffic patterns reveals Sub-Type 2 Messages 2.1 (02 01) and 2.2 (02 02) appearing either in isolation (Figure 7) or as a three-message exchange (Figure 8), both notably occurring without an immediate follow-up data burst. These behaviors exhibit a functional parallelism with 2G-ALE (MS-141A) sounding transmissions, where unilateral or short-handshake bursts are used to maintain channel state and verify path viability independently of active traffic.
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| Fig. 7 : isolated/probe Type 02 Message without an immediate follow-up handshake or data burst |
Hex: 0020020200030b03c0a8650f00000de76996f7d300010000c0a8660f00000646
Figure 8 sows a three-message exchange between nodes 101 and 102 without an immediate follow-up data burst.
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| Fig. 8: three-message exchange without an immediate follow-up data burst |
Analisys of the UDP payloads, IP/UDP encapsulations are omitted.
WG1 Burst UDP Payload: Initial Sounding (Node 101)
Hex: 0020020200030b03c0a8650f00000de76996f7d300010000c0a8660f00000646
Hex: 0020020200030b03c0a8650f00000de76996f7d300010000c0a8660f00000646
WG2 Burs UDP Payload: Response (Node 102)
Hex: 001c0201060019fdc0a8660f0001000ec0a8650f00000de700010002
Hex: 001c0201060019fdc0a8660f0001000ec0a8650f00000de700010002
WG2 payload is 28 bytes and contains the reflected "Echo" of WG1 payload.
WG3 Burst UDP Payoad: Final Confirmation (Node 101)
Hex: 0020020200030b03c0a8650f00000de76996f7d300010000c0a8660f00000646
Hex: 0020020200030b03c0a8650f00000de76996f7d300010000c0a8660f00000646
Sumarizing:
WG1 (The Sound): Node 101 announces itself and sets the Sync ID to 0x0de7.
WG2 (The Call/Response): Node 102 confirms it heard the sound by reflecting the IP .101.15 and the ID 0x0de7 back to the sender.
WG3 (The Conclusion): Node 101 re-transmits its state to ensure the link is locked. This redundancy is the core of the ALE-logic parallelism, ensuring connectivity even if the first packet had jitter.
WG2 (The Call/Response): Node 102 confirms it heard the sound by reflecting the IP .101.15 and the ID 0x0de7 back to the sender.
WG3 (The Conclusion): Node 101 re-transmits its state to ensure the link is locked. This redundancy is the core of the ALE-logic parallelism, ensuring connectivity even if the first packet had jitter.
This confirms that the nodes are handshaking on a state, not just passing data.
Observed sequences also show the presence of Sub-Type 1 Messages 1.2 (01 02), appearing either as isolated/probe burst (Figure 9):
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| Fig. 9: isolated/probe WG burst |
UDP Payload (IP/UDP encapsulation is omitted)
Hex: 00200102000323aac0a8650f00000df1699706f600010000c0a8660f0000064b
UDP Payload WG1 (IP/UDP encapsulation is omitted)
Hex: 00200102000323aac0a8650f00000df1699706f600010000c0a8660f0000064b
Hex: 00200102000323aac0a8650f00000df1699706f600010000c0a8660f0000064b
or occurring immediately before a Type 2 Message inside the same Type 4 data exchange burst. Notably, no ACK is issued by the destination peer (typically Node 102) in this specific sequence.
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| Fig. 10 |
UDP Payload WG1 (IP/UDP encapsulation is omitted)
Hex: 00200102000323aac0a8650f00000df1699706f600010000c0a8660f0000064b
Hex: 002000020003a325c0a8650f00000dea699713f300010000c0a8660f0000064e
Payload A Epoch: 69 97 06 f6 ≈ 07:40:06 UTC
Payload B Epoch: 69 97 13 f3 ≈ 08:35:01 UTC
Delta: 3325 seconds (approx. 55 minutes and 25 seconds).
The fact that Type 04 (Data) follows Payload B immediately, could likely mean that the 55-minute jump in the epoch was a session sesynchronization.
The specific role of Sub-Type 1.2 remains unclear and deserves further investigation.
2.2. Protocol Type Messages
Based on the observed sequences, this WireGuard-like protocol follows a deterministic four-stage lifecycle for link management and data transfer identified by the Type Message IDs:
- Link Initiatior (Type 2 Message): the session originates with an Initiator message utilized to request channel allocation or to "wake up" the remote peer within the STANAG-5066 stack.
- Receiver ACK (Type 1 Message): the responding node returns a Receiver ACK message. This exchange validates link-layer synchronization and confirms that both modems are aligned.
- Link Maintenance/Persistence (Type 3 Message): during periods of data inactivity, the link is sustained via Heartbeat messages. These 16-byte frames likely prevent STANAG-5066 session timeouts and provide the network controller with continuous node reachability status.
- Transport Data (Type 4 Message): once the control plane is stabilized, the Transport Data packets carry the encrypted payload. The persistence of the Receiver Index across distinct captures confirms a long-term security association managed by this custom signaling layer.
Notice the similarity between the two ACK Types 0001 and 0201.
Interestingly, the protocol utilizes a non-sequential Type Message assignment that deviates from standard handshake conventions. Type 02 functions as the Initiator, signaling the intent to establish a link, while Type 01 serves as the Receiver ACK. This inversion suggests a priority-based numbering system or a derivation from a legacy STANAG-5066 signaling framework, where Type 01 is traditionally reserved for link-layer acknowledgments.
3. Some techical observations
3.1. STANAG-5066 addresses
The addresses utilized in STANAG-5066 (Source: 011.020.100.101; Destination: 011.020.100.102) are formally assigned to an Armenian political or organizational network (STANAG-5066 Table N-9 Middle East National Addressing Schema); however, they are likely dummy/fictitious addresses intended to avoid interference with official NATO-standard communications. Regardless, they do not help in geolocation since these represent logical identifiers that reflect organizational affiliation rather than physical geographical location. They identify "who" is communicating within the network, but they bear no relationship to "where" the transmitter is physically located.
The addresses utilized in STANAG-5066 (Source: 011.020.100.101; Destination: 011.020.100.102) are formally assigned to an Armenian political or organizational network (STANAG-5066 Table N-9 Middle East National Addressing Schema); however, they are likely dummy/fictitious addresses intended to avoid interference with official NATO-standard communications. Regardless, they do not help in geolocation since these represent logical identifiers that reflect organizational affiliation rather than physical geographical location. They identify "who" is communicating within the network, but they bear no relationship to "where" the transmitter is physically located.
3.2. Cross-Mapped UDP Architecture (port asimettry)
In a typical internet deployment, WireGuard is symmetric (e.g., Peer A:51820 ↔ Peer B:51820), however analysis of the UDP datagrams reveals a consistent asymmetric pattern:
Node 101 TX Path: Local Port 55504 → Node 102 Remote Port 2753
Node 102 TX Path: Local Port 54107 → Node 101 Remote Port 2754
Looking at previous captures, the local port does not always have the same value but changes (55504,54107,56503,60510,...) while remote ports 2753/2754 remain fixed:
Node 101 TX Path: Local Port (variable) → Node 102 Remote Port 2753
Node 102 TX Path: Local Port (variable) → Node 101 Remote Port 2754
The transition from symmetric to asymmetric UDP ports confirms that this is a Radio-Aware implementation. The cross-mapping of ports 2753 and 2754 serves as a synchronization bridge between the synchronous nature of the WireGuard protocol and the asynchronous, half-duplex constraints of HF.
In a typical internet deployment, WireGuard is symmetric (e.g., Peer A:51820 ↔ Peer B:51820), however analysis of the UDP datagrams reveals a consistent asymmetric pattern:
Node 101 TX Path: Local Port 55504 → Node 102 Remote Port 2753
Node 102 TX Path: Local Port 54107 → Node 101 Remote Port 2754
Looking at previous captures, the local port does not always have the same value but changes (55504,54107,56503,60510,...) while remote ports 2753/2754 remain fixed:
Node 101 TX Path: Local Port (variable) → Node 102 Remote Port 2753
Node 102 TX Path: Local Port (variable) → Node 101 Remote Port 2754
The transition from symmetric to asymmetric UDP ports confirms that this is a Radio-Aware implementation. The cross-mapping of ports 2753 and 2754 serves as a synchronization bridge between the synchronous nature of the WireGuard protocol and the asynchronous, half-duplex constraints of HF.
By separating the RX/TX paths into different ports the software knows that anything arriving on ports 2753/2754 is exclusively incoming traffic from the remote peer, eliminating any risk of processing its own transmitted signals. In essence, the port asymmetry transforms a standard peer-to-peer VPN tunnel into a dual-channel "Virtual Circuit" optimized for the unique HF channel.
Although a search of the IANA port registry yields no official assignments for UDP ports 2753 or 2754, the consistency of their appearance suggests they are de facto service-dedicated ports for this specific protocol.
3.3. End-user Identification and Attribution
Regarding the end-user, it can be confirmed with certainty that the entity is an Italian diplomatic/military body, as previous signal captures have intercepted op-chats conducted in Italian language. Furthermore, multiple UDXF logs support this attribution, identifying the ALE exchanges between nodes 101 and 102 as part of an Italian Military Attaché network.
Regarding the end-user, it can be confirmed with certainty that the entity is an Italian diplomatic/military body, as previous signal captures have intercepted op-chats conducted in Italian language. Furthermore, multiple UDXF logs support this attribution, identifying the ALE exchanges between nodes 101 and 102 as part of an Italian Military Attaché network.
3.4. Node Roles and Network Topology
The specific roles of ALE nodes 101 and 102 remain difficult to define, specifically regarding which functions as the HQ node and which as the remote node. However, it is established that node 101 consistently initiates both the link negotiation and the VPN tunnel, while also managing subsequent data forwarding. Based on standard network architecture, this behavior suggests that node 101 likely operates as the remote station (initiating a "call home" procedure), while node 102 functions as the central gateway or HQ.
The specific roles of ALE nodes 101 and 102 remain difficult to define, specifically regarding which functions as the HQ node and which as the remote node. However, it is established that node 101 consistently initiates both the link negotiation and the VPN tunnel, while also managing subsequent data forwarding. Based on standard network architecture, this behavior suggests that node 101 likely operates as the remote station (initiating a "call home" procedure), while node 102 functions as the central gateway or HQ.
Based on the assumption of an Italian Military Attaché entity, it is highly plausible that the remote station (Node 101) transmits periodic diplomatic/military situation reports (SITREPs) to the central headquarters in Rome (Node 102), likely Ministry of Foreign Affairs or Ministry of Defense.
3.5. Geolocation and Technical Constraints
Similar uncertainties apply to the geolocation of the two transmitters. The TDoA (Time Difference of Arrival) method employed for Direction Finding (DF) requires a minimum dwell time of 30 seconds from a single transmitting source and at least three receivers synchronized to the monitoring frequency.
These conditions are difficult to meet due to the unpredictable nature of the transmissions (they seem to happen only when a "report" is ready) and the handshake mechanism employed, which involves two distinct transmitting sources alternating rapidly. This rapid switching between the initiator (Node 101) and the responder (Node 102) prevents the TDoA system from maintaining a stable lock long enough for a precise fix.
Similar uncertainties apply to the geolocation of the two transmitters. The TDoA (Time Difference of Arrival) method employed for Direction Finding (DF) requires a minimum dwell time of 30 seconds from a single transmitting source and at least three receivers synchronized to the monitoring frequency.
These conditions are difficult to meet due to the unpredictable nature of the transmissions (they seem to happen only when a "report" is ready) and the handshake mechanism employed, which involves two distinct transmitting sources alternating rapidly. This rapid switching between the initiator (Node 101) and the responder (Node 102) prevents the TDoA system from maintaining a stable lock long enough for a precise fix.
3.6. Protocol's timing logic
Examining several captures, significant temporal differences were observed between the WireGuard handshake timestamps in the initiator packets and their actual reception; an example is shown in Figure 11.
Examining several captures, significant temporal differences were observed between the WireGuard handshake timestamps in the initiator packets and their actual reception; an example is shown in Figure 11.
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| Fig. 11: temporal difference |
All data points in the following table were recorded on the same day (2026/02/19), highlighting the intra-day volatility of the protocol's timing logic.
While the synchronization between the packets is evident, the multi-hour gaps between the Internal Timestamp and the Actual Reception time (specifically in Captures C through F) present an unresolved anomaly. At this stage of the analysis, no definitive explanation can be provided for these significant offsets. Several hypotheses remain under consideration: session-based epochs, system clock misalignment (Node 101), or a "store-and-forward" mechanism.
The negative deltas (specifically in Captures A and B) suggest that the internal timestamp functions as an expiration marker, i.e., a Session Validity Deadlines (Time-to-Live): this hypotheses also remains under consideration.
Negative deltas and multi-hour gaps highlight a complex session management logic that requires further data acquisition to be fully decoded and interpreted.
By the way, all the 2024/11/28 captures show similar negative deltas.
Conclusions
In conclusion, the captured traffic likely represents an HF-customized VPN protocol. Although it deviates from the standard WireGuard specifications, its alignment with observed message structures suggests its specialized HF implementation. This adaptation transcends the capabilities of standard Wireshark dissectors, which are designed for "Vanilla" protocols and may not natively support these physical-layer modifications. This analysis remains a work in progress; further captures will be essential to confirm these findings and refine the protocol details.
(1) Transmissions do not appear to follow a fixed schedule. According to UDXF logs, there are multiple frequencies to monitor, making simultaneous tracking difficult unless a polling strategy using ALE software with a scanning receiver or a "staring" monitoring approach is implemented across various remote web-based SDRs:
07780.50, 10220.50, 12110.50, 14963.50, 15906.50
17411.50, 18325.50, 19516.50, 20776.50, 20779.50
(all KHz/USB)
07780.50, 10220.50, 12110.50, 14963.50, 15906.50
17411.50, 18325.50, 19516.50, 20776.50, 20779.50
(all KHz/USB)
