Field Guide · hardware

Also known as: tinySA, tinySA Ultra, tiny SA

The tinySA is a low-cost, open-source handheld spectrum analyzer that puts power-versus-frequency measurement — carrier hunting, harmonic and spurious checks, occupied-bandwidth estimates — into a pocket instrument for well under $100.12 Designed by Erik Kaashoek as a companion to the NanoVNA, it covers roughly 100 kHz to 960 MHz on the original and up to about 6 GHz on the tinySA Ultra, and it doubles as a rudimentary signal generator.

Low in High in Swept receiver spectrum on display
A tinySA: separate low-band and high-band inputs feed a swept receiver, and the resulting power-versus-frequency trace is shown live on the built-in touchscreen.

What it is

The original tinySA is a clever two-path instrument. Its low band (≈100 kHz–350 MHz) uses an Si4432 ISM-radio chip as a genuine narrowband swept superheterodyne receiver with selectable resolution bandwidth, giving good dynamic range and a low noise floor. Its high band (≈240–960 MHz) runs the Si4432 as a harmonic mixer, trading some sensitivity for reach. The tinySA Ultra replaces this with an ADF4351-based synthesizer front end that extends coverage to roughly 6 GHz with better performance. A small touchscreen shows the trace; USB connects it to PC software for larger displays and logging.

In practice

The tinySA’s honest role is survey and troubleshooting, not metrology. It will not match a bench analyzer’s amplitude accuracy, dynamic range, or noise floor, and its input can be overloaded by strong nearby transmitters — always mind the stated maximum input level and use an attenuator when probing a live antenna near high-power sources. Within those limits it is excellent for:

  • Confirming a transmitter is on frequency and checking its harmonics and spurious output.
  • Surveying which frequencies in a band are active before pointing an SDR at them.
  • Estimating relative signal strength and occupied bandwidth.
  • Acting as a simple signal generator source, or — with its output — a scalar tracking-generator sweep of a filter.

Relevance to SDR

For SDR scanning the tinySA is the natural low-cost bench partner to the NanoVNA: where the NanoVNA tunes the antenna and feedline, the tinySA surveys the spectrum — showing whether a control channel or voice frequency is actually radiating, how strong it is, and whether interference or a nearby harmonic threatens the receive band. Any SDR already computes an FFT spectrum, and GopherTrunk’s own waterfall serves the same purpose in software; the tinySA adds a standalone, calibrated-ish view you can carry to the antenna. GopherTrunk does not interface with a tinySA — it is a separate handheld aid, not part of the decode chain.

Sources

  1. Spectrum analyzer — Wikipedia, on swept and FFT spectrum analyzer architectures that the tinySA implements in miniature. ↩

  2. tinySA wiki — official documentation for the tinySA and tinySA Ultra hardware, bands, and limits. ↩

See also