Flex6400 with direct internet connection looses after several hours connection.

stevew_m0rfc · January 11

Hi all,

Have a FLEX6400 (4.1.5.39794) which is wired directly to a 1GB switch with the PC and then off to the router.

The issue is the radio internet status goes to NONE after X hours of use/none use.

My setup is using either DHCP or manually assigned IP address.
SmartSDR and all the other programs connect perfectly.
Network switch is unmanaged with no smart features/firewalls etc.

From the router you can ping the FLEX:
Reply from 192.168.0.40: bytes=64 ttl=64 seq=4 time=0.678 ms

UPnP shows:

FlexRadio SmartLink TLS Port 192.168.0.40 4994 21000 TCP
FlexRadio SmartLink UDP Port 192.168.0.40 4993 22000 UDP

When rebooted you have internet - and Smartlink shows as a green pass.
Leave it connected and powered on overnight and you come back to NONE and no Smartlink.

A reboot always restores the internet connection to the radio.

I *do* want to use it remotely when out of the office, sadly, I cannot at this time without someone rebooting the radio.

73 Steve

John KB4DU · January 12

Just for fun, try bypassing the switch (and the router) with a cable direct to the radio. Let us know what happens. It's probably something in the network. For whatever reason, many GB switches are problematic.

stevew_m0rfc · January 12

Seems a reasonable approach - I did try other ports that were not PoE just in case - and have been able to replicate over night most nights. A radio reboot always clears it - did think it might be the uPnP but even when manually set the issue remains. Will try the router directly to the radio and report.

Mike-VA3MW · January 12

Try the following:

the link.local test as recommended above
Change your switch the radio is connected to to a 100mb/sec switch, at least for a test

Let us know what happens.

stevew_m0rfc · January 13

I have tried a different port on the switch and removed all other protocols, leaving only TCP/IP on the network. The radio is now connected directly.

What I am seeing is that if the radio is left connected but idle for a period of time, the network status changes from Available to None. This happens consistently if I leave it for a couple of hours.

Interestingly, if SmartSDR is left running, the problem does not occur. The drop only seems to happen when I close SmartSDR and leave the radio powered on but otherwise idle.

When the connection is active, everything works exactly as expected. SmartLink works perfectly, and there are no stability issues during use. The problem only appears after the radio has been left unattended.

At this point it feels like something is timing out or putting the interface to sleep when the radio is idle, rather than a general network fault.

Trucker · January 13

From what I have read so far, you haven't tried a direct connection between the radio and your computer. Just connect a known good ethernet cable between the two and run your tests that way. It will determine if the fault is in the radio itself or the computer you are using. If everything works correctly, then the problem exists in the switch itself or some other part of your network setup.

James

WD5GWY

stevew_m0rfc · January 14

Hi Trucker, please see my comment above "The radio is now connected directly." that's plugged into the router.

I did another test and the same issue - it was fine at 23:10 when I hit the sack and at 06:50 it was back to NONE. I am going to look at the DHCP lease time and anything else that gets renewed, although I cannot see why the 6400 does not drop off the network - which makes me think it must be whatever the radio uses to determine if it can reach the internet…

John KB4DU · January 14

This may be a matter of semantics, but the test method we are suggesting does not involve a “router” or “switch” between the radio and the computer.

Mike-VA3MW · January 14

This is the test I am recommending.

Diagnosing Network Issues with a Link-Local Test

A Step-by-Step Guide for FlexRadio Users

Introduction

FlexRadio transceivers rely on stable network connections for optimal performance. If you’re experiencing disconnects, audio dropouts, or other network-related issues, performing a Link-Local Test helps determine whether the problem lies with your radio or your network.

This test directly connects your PC to the radio, bypassing any external network components.

This document outlines how to conduct the test and interpret the results.

Why Perform a Link-Local Test?

Isolates the Problem – Helps determine if the issue is related to your network or the radio itself.
Eliminates Variables – By removing routers, switches, and other network devices, we can focus on potential hardware or software issues.
Simplifies Troubleshooting – If the radio works properly in this test, then the issue is within your network setup.

Step-by-Step Instructions

1. Gather Required Equipment

Your FlexRadio transceiver
A PC or laptop running the latest version of SmartSDR
A single NEW LAN (Ethernet) cable

2. Power Down Your Equipment

Turn off both your PC and your FlexRadio completely.
Unplug any existing network connections to ensure no external devices are affecting the test.

3. Directly Connect the Radio to the PC

Use an Ethernet cable to connect your PC directly to the LAN port on the FlexRadio.
Do not connect the radio or PC to any router, switch, or other network devices.

4. Power Everything Back On

First, turn on your radio and allow it to fully boot.
Then, turn on your PC and let the operating system load completely.

5. Launch SmartSDR

Open SmartSDR on your PC.
In the radio chooser window, check if your radio appears as an available device.

Interpreting the Results

✅ If the radio appears and works correctly:

Try to recreate the same problem. If you are not able to, then this means your radio is functioning properly, and the issue likely stems from your network setup.

The next steps are:

Check for faulty Ethernet cables, switches, or routers.
Ensure your network is properly configured for SmartSDR.
Look for any network congestion or interference.

❌ If the radio does NOT appear or crashes:

This could indicate a hardware or software issue with the radio or PC. In this case:

Restart the test to confirm consistent failure.
If the issue persists, contact FlexRadio Support and report your findings.

Conclusion

The Link-Local Test is a crucial step in troubleshooting network-related issues with your FlexRadio system. By eliminating network components, you can quickly determine whether the problem is internal to your radio or caused by your home network.

stevew_m0rfc · 5:33PM

Cheers Mike, I have been playing more, I have the IOS APP now allowing me to test both on and off lan connectivity - from what I can tell the radio tests internet connectivity by a function call of some form - it would appear that must be the fail here as I can ping the radio posts using a port scan and setting the radio in a DMZ - confirming it can be reached from the internet.

Can you find out what test the radio performs to determine it is connected and what it expects to see back - I can then continue my searching for the issue.

To confirm a reboot always returns normal internet access at the radio - however - SmartSDR locally on the PC and the phone over the WiFi always work.

73 Steve