Solved: No Waterfall and No Audio over LTE/CGNAT – WireGuard + Teltonika RUTX50

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Solved: No Waterfall and No Audio over LTE/CGNAT – WireGuard + Teltonika RUTX50
Hello everyone,
After several days of troubleshooting, testing, and reading through countless forum posts, I finally managed to get my FlexRadio 8400 running reliably over LTE.
I wanted to share my final solution in case it helps other operators who experience similar

The final solution uses a VPS with a fixed public IP address as the WireGuard server. The Teltonika RUTX50 establishes a permanent WireGuard tunnel to the VPS, allowing reliable remote access to the FlexRadio even behind LTE and CGNAT networks. This eliminates the need for port forwarding and provides a stable endpoint for remote connections.


issues such as:
Radio connects but no waterfall
Radio connects but no audio
Intermittent audio drops
SmartLink issues behind CGNAT
Remote operation over LTE not working reliably
What I Discovered
Initially, I assumed the problem was related only to routing, VPN configuration, or CGNAT restrictions.
However, after extensive testing, I discovered that part of the problem was actually hardware-related.
My original setup consisted of:
TP-Link Archer MR200 LTE Router
MikroTik Router
WireGuard VPN
The TP-Link Archer MR200 appeared to have issues with return routing and VPN traffic handling. While connections could be established, data streams required by the FlexRadio were unreliable.
To simplify the setup, I removed the MikroTik entirely and replaced the LTE router with a Teltonika RUTX50.
Final Working Setup
The Teltonika RUTX50 provides:
LTE Modem
Router
Firewall
WireGuard Client
all in a single device.
The FlexRadio is connected directly to the RUTX50 LAN.
Network Example
Internet
|
WireGuard Server
203.0.113.10
10.10.10.1
|
================ VPN ================
|
Teltonika RUTX50
WG: 10.10.10.4
LAN: 192.168.100.1
|
FlexRadio 8400
192.168.100.167

Remote Client
10.10.10.3

AllowedIPs:
10.10.10.0/24
192.168.100.0/24
Why This Works
The WireGuard server has a public IP address and acts as a central access point.
The Teltonika establishes an outbound WireGuard tunnel to the server, which means the solution works even when the LTE provider uses CGNAT.
This completely avoids the need for port forwarding on the LTE connection.
Current Status
The system is now operating reliably.
I occasionally notice minor data flow fluctuations which appear to be related to LTE network quality rather than the VPN configuration itself.
Waterfall and audio are fully functional.
Conclusion
If you are struggling with:
No waterfall
No audio
LTE remote operation
CGNAT limitations
Unstable VPN routing
consider simplifying the setup and using a Teltonika RUTX50 with WireGuard.
In my case, replacing the TP-Link Archer MR200 and removing the MikroTik completely solved the problem.
Hopefully this saves someone else many hours of troubleshooting.

Please note that this solution is based entirely on my own experience and the specific hardware and network environment that I am using.
I cannot guarantee that it will solve the same issues for everyone, as LTE providers, network configurations, VPN setups, and hardware platforms may behave differently.
I am simply sharing what worked in my case after extensive troubleshooting and testing.
I do not claim that this is the only solution or the best solution. It is simply the solution that worked for me.
Hopefully it provides useful ideas or a starting point for others facing similar problems with FlexRadio remote operation over LTE and CGNAT.
If it helps even one operator save a few days of troubleshooting, then it was worth sharing.

Note About IP Addresses

All IP addresses shown in this document are example addresses used for documentation purposes only.

The public IP address, VPN addresses, and private network ranges shown above are not the actual production addresses used in my installation.

73 and best regards,

HB9TWT