MF-01·05 · Signals & Comms

Skipline

coming soon

HF chat that works with the internet switched off. A tablet on a local hotspot drives a mini-PC that drives the radio, and every font and file is served from the box in front of you.

Full screenComing soon

Part no.	MF-01·05
Room	01 · Signals & Comms
Status	coming soon
Does	VARA HF · 283 radios via Hamlib · zero external calls
Runs as	Operator console · demo modem in the browser · the real one runs on the box
Made with	FastAPI · WebSocket · VARA HF · Hamlib rigctld · ardopcf

Key plan · room 01, Signals & Comms

Fig. 1 · Skipline, on the bench: power it on to run it hereMF-01·05

01Why it exists

Comms that survive the infrastructure going away

Built for a friend who needs communications that keep working when the grid and the internet don't. HF radio reaches hundreds to thousands of miles off the ionosphere, and the VARA modem turns it into a data link. Skipline (formerly NovarAC, and before that PyVarAC) wraps all of it in one browser screen any ham can run from a tablet, with no Windows desktop to babysit and no assumption that the internet still exists.

02Parts list

Rig controlA parsed Hamlib database of 283 radios from 62 manufacturers, driven through rigctld: frequency, mode, band presets and push-to-talk over CAT, DTR, RTS or VOX.
Chat over VARAA WebSocket bridge to the VARA HF modem over TCP: link to a callsign and talk, with signal-to-noise and speed level on every link.
Offline means offlineThe first build quietly pulled Google Fonts. It was stripped, five fonts are now served by the box, and the rendered page was checked for any outbound request.
Demo modeWith no modem attached, the server simulates one, and so does the console below: tune, key up and hold a pretend QSO.

03Instruments

HF conditions

Space weather

04Construction

The stack

Transport: a tablet browser over a local WiFi hotspot to the mini-PC, with no router upstream and no DNS. Radio link: the VARA modem on the PC, with a Digirig or SignaLink to the rig; the audio never touches a network. Fallback: ardopcf is the documented open-source path and runs on a Pi if VARA's closed binary ever becomes a problem.

FastAPIWebSocketVARA HFHamlib rigctldardopcf

Six files

launch.py starts it (with an optional tunnel when you do want it reachable). server.py bridges the browser to the modem. rig_control.py wraps rigctld, polls every two seconds and marks the rig lost after five straight failures. rig_list.json, index.html and the fonts are the rest. No build step.

05Tolerances

HF needs a licence, a rig, an antenna and a PC running VARA. The console on this page is a demo: the modem and the far station are simulated. The real one is served by the box itself, so it works with no internet at all.

what it is not, said plainly

06Inscription

Amber, deliberately. The first pass was too gloomy to read at 3am.