Article

Share a working circuit instead of a screenshot

Somebody posts a screenshot of a Smith chart and asks why their match is not working. Now everybody guesses, because a picture of a circuit is not a circuit. There is a better way to ask.

The whole design goes in the address

File → Copy Share Link puts the frequency, the load, every component with its Q, the length units, the sweep range and the chart overlays into a web address. Open that address and the design is rebuilt exactly, in whatever browser, with no account and nothing to install.

A four component match comes to about 120 characters. Here is a real one:

quicksmith.online/#eyJ2IjoxLCJmIjoxMDAsImUiOltbMSwicngiLDUwMCww...

It is not a reference to a design stored on a server. The design is the string. Nothing is uploaded, nothing expires, and there is no database that can lose it. Paste it in an email in ten years and it will still work as long as the page is still there.

What it is good for

Asking a question properly. "Here is my antenna and here is what I tried" as a link, instead of a screenshot and a list of values that somebody has to retype. The person answering can move a value and see what happens, which is the difference between a guess and an answer.

Answering one. Reply with a link to the fixed version. They can see what you changed by opening both.

Teaching. Every worked example on this site ends with Open this circuit in QuickSmith, and every article that describes a network does the same. That is a share link. A reader can take the design apart rather than trust the prose, which is a much better position to put them in.

Notes to yourself. A link in a lab notebook or a ticket is a complete record of what you tried, and unlike a screenshot it is still editable next month.

Measured loads travel too

If your load is a Touchstone file rather than a typed impedance, the measured points go into the link as well. That makes it longer, a few hundred characters rather than a hundred, and it means what the other person opens is your antenna and not an idealisation of it.

What is deliberately not in it

The link is trimmed hard, because a long URL gets mangled by mail clients and chat apps. Empty ladder slots are dropped. Values are rounded to six significant figures. Settings still at their defaults are left out entirely, so a design at 50 ohms with a velocity factor of 1 carries neither.

That trimming is checked rather than assumed. Every case in the regression suite encodes a design, decodes it, solves both, and requires the answers to agree. The claim is not that the string looks right, it is that the design survives the round trip.

The other ways out

A link is the right thing for a conversation. For other jobs:

• File → Save File writes a .sch, which is the actual file format and the thing to keep if you care about it.
• File → Chart as SVG gives vector art for a report, and Print Chart prints just the chart in the light palette whatever your screen is set to.
• Data → Export Touchstone writes the network as an .s1p for whatever tool comes next, and Export Sweep (CSV) gives you the numbers as a spreadsheet.
• File → Save Session keeps your work in this browser across a reload, which is not sharing but is the thing people actually want when they close a tab by accident.

A small request

If you answer RF questions on a forum, in a club newsletter, on Stack Exchange, try replying with a working circuit instead of a picture of one. It costs one menu item, and the person on the other end gets something they can turn the knobs on.