RF Test Engineer

The Jacksonville RF/cryo lab is where superconducting devices stop being theoretical and start producing data. Vector network analyzers, cryogenic probers, dilution refrigerators, and the microwave signal chain that ties them together — all of it has to run, stay calibrated, and produce measurements other teams can actually build decisions on. This role owns that.
You will run day-to-day RF and microwave measurements on superconducting device samples, maintain the instrumentation that makes those measurements possible, and serve as the on-the-ground RF authority for a physics team that mostly works remote. You will work directly with device physicists, fab engineers, and the rest of the test group in a flat, matrixed organization. There are no layers between you and the problem — and no one to fall back on when an instrument drifts at 2am.
In twelve months, the calibration discipline, measurement protocols, and equipment logs you set up should be the reason the rest of the company trusts the data coming out of this lab. As the program scales, this is the seat that trains the next bench engineers — including anyone we bring on for specialized SQUID microscopy work.

- Own day-to-day operation of the Jacksonville RF/cryo test lab — instruments running, fridges loaded, samples measured, data captured.
- Execute high-precision RF and microwave measurements on superconducting device samples, including S-parameter, noise, and time-domain characterization at cryogenic temperatures.
- Maintain the instrumentation that keeps those measurements honest: VNAs, cryogenic probers, microwave components, cabling, connectors, and the cold-chain signal path end to end.
- Define and hold the line on calibration schedules, cable management, fixturing standards, and equipment logs — the unglamorous discipline that separates trustworthy data from noise.
- Support scanning SQUID microscopy measurement campaigns when required, and own the training pipeline that brings junior staff up on SSM technique as the program scales.
- Capture, document, and hand off test data to the remote physics team in a form they can actually reason from — including the context, conditions, and caveats that make the numbers meaningful.
- Drive root-cause investigation when measurements disagree with theory or with each other — fixture, calibration, sample, or physics, you figure out which.
- Partner with device physicists, fab engineers, and other test staff to keep measurement methodology and process feedback loops tight.

- Direct, hands-on experience running RF and microwave lab equipment in a measurement-intensive environment — bench time, not just simulation, EDA, or design work.
- Working experience in cryogenic test environments — dilution refrigerators, pulse tubes, cryogenic probers, or equivalent — including the practical realities of thermal anchoring, cold-chain signal integrity, and what breaks at low temperature.
- Deep, practical fluency with precision S-parameter, noise, and time-domain measurements: calibration choices, error budgets, fixturing, and the places those assumptions quietly fail.
- Discipline around the operational side of a lab — calibration cadences, cable and connector hygiene, equipment logs, and the kind of documentation that lets the next person reproduce what you did.
- Track record of running equipment independently and keeping it running without on-site senior supervision.
- Comfort operating in a startup environment where priorities shift, procedures are still being written, and "we don't have one yet" is a frequent answer.

- Direct experience with scanning SQUID microscopy — or substantive exposure to programs that ran it. This is a rare skill set globally and a strong differentiator.
- Background supporting SFQ, AQFP, qubit, or superconducting detector measurement programs at a research university, national lab, or industry group.
- Time at NIST, MIT Lincoln Lab, Sandia, or a comparable national lab in a cryogenic RF or superconducting characterization role.
- Python and scientific computing skills for measurement automation, instrument control, and turning one-off scripts into reproducible measurement pipelines.
- Experience with millimeter-wave measurement above 20 GHz, low phase noise characterization, or noise-figure work where uncertainty quantification actually mattered.
- EM/microwave simulation experience that you've used to predict and then explain real measurement outcomes — not just generate plots.
- Evidence of ownership outside the job description: instruments you built, fixtures you designed, methodology you published, or labs you stood up from scratch.

Snowcap is a small, technically elite team doing measurement work that has never been done at commercial scale on these devices. There is no inherited test playbook for most of what you will be asked to measure. You will write it, refine it, and defend it when the data argues back.
We are a flat, matrixed organization. The physics team is largely remote, which means you are the eyes, hands, and judgment on the lab floor. You will work daily with physicists, fab engineers, and test peers — directly, without layers — and when an instrument starts drifting or a fixture starts misbehaving, the call on what to do is yours.
This role is on-site in Jacksonville. The lab is real, the fridges run cold, and the devices coming off the line do not always agree with theory. If you need a mature lab with a settled procedure binder and senior bench engineers next to you, this is not the right fit. If you want to run the lab — and have the discipline to keep it trustworthy — you are in the right place.

Snowcap builds superconducting compute. (Edit in admin.)

Full medical, dental, and vision · 401(k) · Relocation assistance available for candidates outside the area.
Base salary range is shown in USD and reflects the Jacksonville Metro labor market for this role, calibrated against NASA federal pay scale (Palm Bay locality) and comparable FL semiconductor / defense private-sector roles. Actual offer depends on experience, skills, and seniority, and is exclusive of equity, bonus, and benefits. Florida has no state income tax — relocating candidates should factor that into side-by-side comparisons with high-tax-state offers.
Based in Jacksonville Metro, FL · On-Site.

Snowcap is an equal opportunity employer. We do not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or any other protected characteristic. (Edit in admin.)