T-1 RTN with public IP

Eric Tweet

Active Member
Just a peek behind the curtain of my current setup (pay no attention to the mess!)...

Recently I've decided to ditch my Topcon that I've had set up as an RTN for the past ~5 years. I've previously thought that it wasn't any better/worse than my T-1 pair that I use for work in remote locations or wherever internet/cell is spotty. However, after discovering that both of my T-1s are 4-constellation-enabled, despite those options being disabled, and having a new LS+ as my rover, I've re-purposed my old T-1 rover as my new RTN. (My T-1 base remains in its travel case for remote UHF setups)

So here she is:


Yes, it's a temporary fix just to get 4 constellations, and I do have to bring it in for charging and all that. I plan on upgrading to a Delta or some such other permanent solution in time.

"But wait!", you say, "You said RTN with public IP. Where are the wires to your server rack? Did you jam an ancient sim card in there with a static IP?"
So glad you asked!

It goes something like this: I have the T-1 configured to jump onto my office wifi, with its correction and configuration ports open. So my office computer has easy access to the base, being on the same private network. Also on the office computer are 2 things - a port forwarding program and an SSH client. I establish an SSH tunnel from the office PC to a VPS and enable client-to-server port forwarding through the tunnel. Those ports are also forwarded locally from the office computer to the T-1. The VPS is then listening on those ports (public-facing), so all I need to do is hook my LS up to my phone/hotspot and have the RTN APN directed to the PUBLIC IP address of the VPS, with the appropriate ports. That's it! Now I have a 4-constellation RTN with a public IP address to access anywhere.

One of the cool benefits of having the config port open is that when I'm done with work in the field for the day, I can hop in the truck, connect to it with my LS+, stop the base, and begin downloading the day's file. By the time I get home, it's downloaded and I can just grab the T-1 and pop it on the charger.

To mitigate some of the head-scratching I see you engaging in, here's a diagram which might paint a better picture:


Really, if my office internet had a static IP, I could just forward the ports through the router to the T-1, and direct my LS to connect to that. But hey, here we are!

Eric Tweet

Active Member
That was my guess too. Really I'm just happy to have more than a couple GGD signals available, particularly for "free" despite the options for those constellations showing 0.

I have a third T-1 which I upgraded the firmware on (since it had old enough firmware that it couldn't connect to wifi), and now, despite being wifi capable after the upgrade, it seems that it's generally unusable. I tried to set it up as a base with the LS+ after the upgrade and got the dreaded "options expired" message. So I'm mildly terrified of upgrading the firmware on my good units. :p But they work fine, so I think I'll just leave well enough alone.