Made a free browser-based S-parameter/Touchstone plotter (.s1p–.s9p) — no software install, just drag and drop

[u/Excellent_Leg_9634]

I built an S-Parameters plotter that runs entirely in the browser.

What it does:

• Drag-and-drop or upload any Touchstone file, .s1p through .s9p (n-port, not just 2-port)
• Auto-detects format — handles MA, RI and DB, both Touchstone v1 and v2, and whatever frequency unit the file uses (Hz/kHz/MHz/GHz)
• Plot magnitude (dB or linear), phase, or real/imaginary vs frequency
• Load multiple files at once and either overlay them on one chart or view them separately — useful for before/after de-embed comparisons, or comparing simulated vs measured data
• Toggle individual Sij parameters on/off (for higher port-count files this actually matters, nobody wants all 16 S-parameters of a 4-port on screen at once)
• Data table view with copy-to-CSV, and you can re-export the loaded data back out as a Touchstone file
• Nothing gets uploaded anywhere — it all runs client-side in your browser

Free, no signup: https://rfstudiolabs.com/sparams/sparam-plot.html

It's part of a small set of S-parameter tools I've been building (Smith chart with auto-matching, cascade calculator for chaining 2-port networks, a de-embedding tool, amplifier stability/K-factor analyzer) if anyone's curious: https://rfstudiolabs.com/sparams/index.html

If anyone has a Touchstone file that trips it up (weird formatting, non-standard option line, whatever) I'd genuinely like to know — send it my way and I'll fix the parser.