Introduction

The TinySA is a low-cost handheld spectrum analyzer, with a price of around 60 €. We are going to see what we get with this price and in future articles we know how to get the maximum of this device for signal measurement and generation, as well as to use it for EMC troubleshooting.

Where to buy

There are many online shops selling tinySAs. Be aware that there are some clones, so be really careful when selecting the place to buy it. Some of the verified vendors are in this list:

Please, if you purchase a good one, let us know within the comments section, we will add the supplier to the list. 

Specifications

According to the manufacturer, the tinySA has the following capabilities:

  • Two inputs, high-quality MF/HF/VHF input for 0.1MHZ-350MHz, lesser quality UHF input for 240MHz-960MHz.
  • Switchable resolution bandpass filters for both ranges between 2.6kHz and 640kHz
  • Color display showing 290 scan points covering up to the full low or high-frequency range.
  • Input Step attenuator from 0dB to 31dB for the MF/HF/VHF input.
  • When not used as Spectrum Analyzer it can be used as Signal Generator, MF/HF/VHF sinus output between 0.1MHZ-350MHz, UHF square wave output between 240MHz-960MHz.
  • 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
  • Rechargeable battery allowing a minimum of at least 2 hours portable use
  • Max input level +10dBm.

They are aware that, because of its low price, you cannot expect a perfectly performant system within all the frequency bands. Therefore, they warn about some limitations:

  • The internal phase noise sets a clear lower limit for phase noise measurements.
  • The minimum resolution bandwidth of 2.4kHz makes it impossible to see more spectral detail.
  • The high input (240MHz to 960MHz) has very limited image suppression and only one level optional built-in attenuator which makes it difficult to interpret complex signals.
  • The high input optional input attenuator is frequency-dependent and varies between 25dB and 40dB.
  • At lower resolution bandwidths (below 30kHz) the measurement time per point starts to increase due to the resolution filter implementation. Careful use of the FAST sweeping mode may reduce this time increase.
  • The performance limitations of the shielding and the filters may lead to certain images and spurs being visible but certain functions like spur suppression and switching to below IF may help detect and/or reduce these spurs and images.
  • Below 0.1MHz the sensitivity starts to reduce.
  • Below 1MHz it is recommended to disable the AGC and possibly enable the LNA to get best measurement quality.
  • When using the supplied telescopic antenna or a low RBW one should be aware of the radiation from the tinySA MCU on 48MHz and its harmonics.

Packaging

The Spectrum Analyzer TinySA comes with the following elements:

  • Cable USB type C
  • A pick
  • Two cables SMA to SMA rg174
  • One SMA female to female connector
  • One SMA telescopic antenna
  • One hand rope

The pick is to use the touchscreen. Due to the reduced screen size, this pick is a critical element, however, it is not impossible to use your hands, but the process will be surely slower.

Connectivity

  • It is possible to connect it to a computer through a USB port. Then, we can visualize data on the PC screen instead of on the little tinySA screen.
  • There are two SMA ports: a high-frequency port, for signals from 240 MHz to 960 MHz, and a low-frequency port, for signals from 100 kHz to 350 MHz. 

Software

There is a Windows application to read and show the data, named tinySA-App. The authors claim that it is not finished, but to visualize some basic measurements, it works very fine. It can be downloaded from this link: http://athome.kaashoek.com/tinySA/Windows/

Working modes

The tinySA can work in four different modes:

  • Low input: to measure signals from 100 kHz to 350 MHz.
  • High input: to measure signals from 240 MHz to 960 MHz.
  • Low output: to generate signals from 100 kHz to 350 MHz.
  • High output: to generate signals from 240 MHz to 960 MHz.

There is also an additional mode, named Cal output, which is only used to calibrate the signal generation function.

First steps

Check that your tinySA is a good one

Since there are some clones that are not technically good, let’s be sure that our own tinySA is a good one to avoid future frustrations. The method to verify is simple: connect the high connector to the low connector and run the Self-test following the steps: touch the screen → Config → Self Test.

Once you run it, you should see the following picture:

If you get the same image, congratulations! Your tinySA is a good one. If any test fails, verify the set-up and, if everything is correct, contact the supplier to ask for a replacement or a refund.

Configure the PC Software

Even though this stage is not compulsory, it is always recommendable to have the full test set up before starting the measurements.

  • Download the tinySA-App, it does not require installation.
  • Connect the tinySA to your PC using the USB cable.
  • Verify that the driver has been correctly installed in the Device Manager panel.
  • Execute the TinySA-App
    • Select the serial port (Starting with COM), the baud rate, 115200, and connect to the tinySA.
  • Do some tests, for example:   
    • Execute a single scan
    • Execute a continuous scan. Depending upon the measuring parameters, this process can take some time.
    • You can perform measurements using the touchscreen and once you have everything prepared, capture a screenshot. In this way, you do not risk blocking the communication channel.

First measurements

Let’s perform some simple measurements, just connecting the tinySA to a function generator. For this post, a Siglent SDG 805 was used.

Sinusoidal signal 5 MHz – 10 mVpp

Tiny SA measurement of a 5MHz 10 mVpp sinusoidal signal
Tiny SA measurement of a 1MHz 10 mVpp sinusoidal signal

Square signal 2 MHz – 10 mVpp

Tiny SA measurement of a 2MHz 10 mVpp signal
Tiny SA measurement of a 2MHz 10 mVpp square signal

Conclusions

The TinySA is a very low-cost device with a lot of potential. There are many options to discover and take advantage of. We do not have to forget that its firmware is being continuously updated, so possible flaws that can be corrected will be implemented in the future.