Troubleshooting Smartlink Issue Over Cellular Hotspot

Mike_N1EN

I am a relatively new 6600M owner.

On a recent quick trip out of town, I had hopes of making a few contacts from my hotel room...but I wasn't able to connect, despite (I thought) having Smartlink set up correctly.

I've played around a little more this morning...and I'm stumped.

Router at home is a Ubiquiti Dream Machine. The 6600M is connected via ethernet. UPNP is enabled for the VLAN the 6600M is on. Running SmartSDR 3.2.39 on Windows 11. I've confirmed that SmartSDR, SmartCAT, and DAX are all allowed through Windows firewall on both "Public" and "Private" networks.

Within the same VLAN inside my network, I'm able to connect to the 6600M from any computer as expected.

From the SmartSDR login screen, SmartLink Setup » Test gives me a green ball.

If I put a computer on a different VLAN from the 6600M, I am able to get a SmartLink connection to the 6600M.

My cell phone is a Pixel (Android) on AT&T. If I enable the hotspot on my Pixel, and connect to it, attempts to make a SmartLink connection result in an error message "Radio connection Failed. Unable to connect to the radio. Please try again."

What am I missing?

Mike-VA3MW

Hi Mike

Good work and good description.

It sounds like the radio is setup ok with SmartLink and you have confirmed that it works from a different VLAN using the SmartLink connection protocol. Don't touch anything on the radio side. That isn't the problem.

It sounds like your Pixel is blocking some of the communications and that is where I would focus. Are there any firewalls on the Pixel that needs some new rules? Sorry, I don't have any experience with the Pixel.

73

Mike_N1EN

The Pixel is running stock Android 12, and I don't have any intentionally-run firewall tool running.

So, perhaps a better question would be: is there something about hotspotting on Android (or AT&T wireless) that would interfere with a SmartLink connection?

I have had issues in the past with AT&T blocking traffic to certain ports, but considering the quasi-random ports SmartLink seems to be opening in the LAN's router, I wouldn't have thought that would be an issue.

Mike_N1EN

And one other update for posterity's sake.... Over lunch, I routed all traffic from my laptop through a VPN, and was able to connect via SmartLink.

It's something with either the Android hotspot or AT&T's network. That's kind of sad, since I primarily hotspot through my phone when traveling, to avoid the perils of public/shared WiFi.

Mike_N1EN

Another update for posterity -- earlier today, I tried a different SIM in my phone (Google Fi, which was routing through Sprint/T-Mobile)...and had the same failure to connect.

Is anyone using a cellular hostpot to connect via Smartlink? If so, could you share details?

Alternatively, is there a suggested way to troubleshoot why a connection might fail?

KD0RC

Hi Mike, I often use my Verizon Android phone as a WiFi hotspot to connect via SmartLink. I don't do anything differently in SmartSDR from a normal (wired) login at home.

When I am in a more urban environment (or touristy place), this tends to work without issue. When I am up camping in a remote area, sometimes it works great and sometimes not so much. I attribute it to the bandwidth available at the cell tower, as sometimes I have a very strong cell signal, but can't stay connected. Sometimes I have a pathetically weak signal, but can operate without issue. I can never tell which way it will be until I attempt a connection.