TinySA Ultra: A low-cost spectrum analyzer that fits in your pocket

This palm-sized, battery-operated instrument can help you diagnose EMC problems.

While RF spectrum analyzers have dropped in price to affordable levels, here’s a $260 portable unit with 6 GHz bandwidth that can fit in your hand. The TinySA Ultra is the most recent of a string of miniature analyzers, including features of much higher-priced models. Here’s my hands-on review.

TinySA spectrum analyzer — Figure 1. The TinySA Ultra tunes from 100 kHz to 6 GHz and offers many of the features found in benchtop analyzers. Photo by Kenneth Wyatt

Erik Kaashoek in the Netherlands designed the TinySA (Figure 1) based partly on the NanoVNA firmware, which supports the analyzer. This is where to find outlets to purchase legal versions, as several clones perform poorly. For example, I purchased mine through Amazon from the SeeSii store. It’s also available from R & L Electronics (in the US) for $139, about half what I paid through Amazon.

Basic Description
The analyzer can tune from 100 kHz to 960 MHz (6 GHz in Ultra mode). Resolution bandwidth ranges from 200 Hz to 850 kHz in roughly 1:3:10 increments. The vertical axis defaults to dBm, but you can set it to dBµV (among other choices), which is useful for EMC measurements. You can also opt for a 20 dB low-noise amplifier (LNA) that may be selected. Settings may be made via a touch screen or a toggle switch on the top.

The designer cautions users not to exceed a signal power greater than +6 dBm at the input. When measuring unknown signals, you should use an external 20 dB attenuator on the input. Using the unit with an antenna is relatively safe unless you find yourself close to powerful transmitters.

Besides the spectrum analyzer, the TinySA also has an RF generator function. Unfortunately, this is a separate mode and not a tracking generator. The generator can produce sine waves from 100 kHz to 800 MHz or square waves from 100 kHz to 4.4 GHz. Figure 2 shows a block diagram of the system.

TinySA block gragram — Figure 2. The TinySA Ultra uses a conventional swept superheterodyne topology with a local oscillator. The RF generator is a separate function and can be used for calibration. Image: TinySA.org.

Features include:

The TinySA screen is a 4-inch touch screen.
Spectrum Analyzer for 0.1 to 800 MHz or, with Ultra mode enabled, level calibrated up to 6 GHz. It’s possible to observe signals up to 12 GHz.
Signal Generator with sine wave output between 0.1 to 800 MHz or square wave up to 4.4 GHz or RF test signal output up to 5.3 GHz when not used as a spectrum analyzer.
Switchable resolution bandpass filters from 200 Hz to 850 kHz built-in 20 dB optional LNA.
Color display showing max 450 points providing gapless covering up to the full frequency range.
MicroSD card slot for storing measurements, settings, and screen captures.

Also:

Input Step attenuator from 0 to 31 dB (cannot be used in combination with LNA).
A built-in calibration signal generator that is used for automatic self-test and (low) input calibration.
Connected to a PC via USB, it becomes a PC-controlled spectrum analyzer or signal generator.
Rechargeable battery allowing a minimum of 2 hours of portable use.
Max input level +10 dBm.

Basic EMC menu setup
The menu system is quite extensive, and I will only describe the settings commonly used for EMC measurements. Clicking anywhere on the screen will bring up the Main Menu (Figure 3). From here, you can select any setting. The TinySA organization publishes an extensive menu tree.

Figure 3. A screen capture from the TinySA Ultra shows the main menu.

EMC Settings
Here are the basic settings you’ll normally use for EMC measurements. You might find many others useful, but these should get you going quickly. Click anywhere on the screen to bring up the Main Menu, then follow the guide below.

Select SA or RF Gen: Mode > select spectrum analyzer or RF generator.

Setting Ultra Mode: Configure > More > Ultra Mode (this allows measurements up to 6 GHz).

Set Date/Time: Config > Date/Time.

Set Frequency: press Frequency > Start and Stop (or Center Freq and Span).

Set Resolution Bandwidth (RBW): press Level > RBW > select 100 kHz for measurements between 30 MHz and 1000 MHz (or 10 kHz for measurements from 100 kHz to 30 MHz).

Set Reference level: Level > set to Auto or Manual (I usually leave as Auto).

Vertical Units: Level > Unit > select dBµV (for typical EMC measurements).

Max Hold: Trace > Calc On > Max Hold (can also set averaging and quasi-peak)

Markers: Marker > select up to 8 markers, which will automatically find the largest peaks.

To change the default startup configuration, first set up the analyzer as you wish, then press Preset > Store > Store As Startup. Other presets may be stored in the “Store n” selections. For example, I stored a frequency sweep of 1 MHz to 500 MHz in dBµV as a common EMC troubleshooting setting.

Figure 4. The GetScreenSE software can grab and save screen captures in PNG format.

Screen Captures
There are two methods for saving screens: carefully touching the “SD” icon in the lower left or using the free GetScreenSE.Zip software (PC only, via). You may need to join the TinySA Groups.io to access this. Figure 4 shows the screen capture software.

Once you execute the software, select COM3 (leaving all other defaults the same), then “Open COM Port” and “Get screenshot.” Once the screen capture is displayed, then Save As (filename). This defaults to the date and time of save but can be modified to suit. There are drawing and annotation tools I haven’t tried using yet and will “leave that to the student”.

Figure 5. Radiated emissions from a Tesla Model 3. The TinySA Ultra was tuned from 100 kHz to 100 MHz and merely sitting on the passenger seat in Max Hold mode with the supplied telescoping antenna. Caution: this is not an official EMC test, but it does show a couple of broadband peaks (markers 2 and 3) while driving. I was surprised to find no emissions in the AM radio band.

Using the TinySA Ultra in the Field
I’ve used this in the field to measure the radiated emissions from a Tesla Model 3 rental vehicle (Figure 5) and to assist in tracking down interference to a gas station price sign that used the 915 MHz ISM wireless band for remote control of the daily price changes (Figure 6). By using directional antennas, I found that the interference was coming from an adjacent drug store that also used the 915 MHz ISM band for its video surveillance system.

Summary
The TinySA Ultra is quite an amazing and sophisticated spectrum analyzer. The $260 price would be attractive to not only hobbyists but, as demonstrated, could also be used in professional applications. Battery life is very good (advertised as two hours), and setup is quick and easy. The packaging is also much more robust than earlier analyzers in the series. The fact it can extend up to 6 GHz is also impressive. In addition, the “groups.io” user group is quite active, and the firmware gets updated frequently. Recommended.