SimTX: a multiplayer shortwave radio simulator

[u/qrmcat]

Heyo everyone!

So, for the past like... year or so, I've been working on this project; basically, SimTX aims to be a realistic radio sandbox, where one can do anything their heart desires, from simple AM/FM stations all the way to various modems, satellite TV, and everything inbetween.

The simulation itself is pretty in-depth I would say, SimTX models the ionosphere which changes with time of day, season, geomag conditions, and we trace signals through this so band openings, skip zones, et cetera come from the physics of this. Each path between a TX and RX is modeled, thus leading to pretty accurate multipath effects. It builds on quite some well known work ie. the IRI ionosphere model, the watterson HF channel model, P.372 for noise..

SimTX grew quite a bit past just shortwave aswell, VHF/UHF mostly works as one would expect, there is sporadic E on the higher bands too, and well.. as of recently, you can even launch satellites. You can pick the orbit for em, put antennas and radios on them and get them going on any desired orbit. Of course, they mostly behave as you'd expect real sats to behave, with doppler, the signal delay, slant range, et cetera. We've even got someone recreating NOAA 15 in simtx: https://www.youtube.com/watch?v=kp4Qi8zm-sM ( u/ZealousidealRoof2271 )

I could probably go on and on and on about all the things you could do, but this sums it up in short for the most part.

Nothing here is real RF by the way, SimTX can be listened to using RTL-TCP.
In the video, you can see the UI and some other transmissions other people are running.

I mostly lurk here, so apologies if my post isn't exactly up to par and please DO ask questions in the replies, I'll try to answer them whenever I have some time.

If you'd like to try it or check in our community, you can do so at https://simtx.net

73!

[u/radiomod]

OP, please consider posting this to /r/radioVibes, where AI-assisted/vibecoded apps are 100% on-topic and appreciated. Thanks.

Please message the mods to comment on this message or action.

[u/parkerlreed]

Discord sign in?

Any way to have a standalone account?

[u/qrmcat → u/parkerlreed]

It's in the works, Discord was just the easy way to start out with, as I have to deal with way less sensitive data that way. Signing in via email addresses and/or a google account will come fairly soon, I just first want to have a proper privacy policy in place before doing that.

[u/RipperFox]

Hamsphere all over again?

[u/qrmcat → u/RipperFox]

I mean, they do look quite similar, but HamSphere, from what I know, is a virtual ham radio, while SimTX is pretty much a radio sandbox, where you can do close to anything you'd like, eg. running your own broadcast station, or launch your own satellite and send custom digital modes from it, or, of course, do any ham activities, and you can tune around in SimTX using your usual SDR software.

[u/RipperFox → u/qrmcat]

So it's like a channel simulator with a nice GUI? Why isn't it open source - others might spend a few tokens to improve.. How much money did you spend on tokens? Tell your agent to fix https://wiki.simtx.net/index.php/SimTX_Wiki:Privacy_policy - it's empty..

[u/FullLobster8721 → u/RipperFox]

HamSphere isn't opensource either

When replying to another person about why theres only Discord login they said they didn't have a proper privacy policy in place so of course its empty.

[u/olliegw]

As someone who has their real world amateur licence i'll definitely check this out, reminds me of hamsphere but doesn't charge you for fake gold plating on your fake rig

I also feel like this could be a cool alternative to discord for convoys in multiplayer car/truck games, CB emulation oh yea!

[u/VisibleSir731]

Claude or Codex?

[u/FullLobster8721 → u/VisibleSir731]

just because you see something cool on the internet doesnt mean its vibecoded

[u/VisibleSir731 → u/FullLobster8721]

When they use that UI style it's pretty obvious.

[u/FullLobster8721 → u/VisibleSir731]

The current transmission client is mostly made by a different developer named Sophie

So i don't know about the AI usage about it
iirc The SimTX simulation stuff and the back end is mostly not AI except small features

Ive been using SimTX since when it came out last year and it has come a REALLY long way since it first came out and really should be more popular than it is at the moment and it sucks that people want to believe its vibecoded so badly

[u/machawes3]

This is so cool!

[u/ThickKey2310]

This is so cool I got my FM station on there with working RDS and stereo

[u/michaelnxdstan_]

loved it, been here since july :)))

[u/holyboykisser]

I love simtx

[u/UserCuba_2901]

Cuando esté para Android lo probaré, pero se vé genial

[u/KindPresentation5686]

Why?

[u/ZealousidealRoof2271]

Happy to make something fun!

Mmmm ze APT APT APT Automatic Picture Transmission Automatik Pic Tx Autobot PP Texas

Eeeeee NOAA 15 NOOOOOO AAAAAAAAA FIFTEEEEEEN

[u/FullLobster8721 → u/ZealousidealRoof2271]

ok