tinySA | Main / Frequently Asked Questions

Common questions

Question: Is the tinySA really doing what is promises?
Answer: At https://groups.io/g/tinysa you will find a user community with more than 2000 happy users as members.
Question: Is the tinySA using the same HW as the nanoVNA?
Answer: No, the tinySA HW is very different from the nanoVNA and specifically optimized for its spectrum analyzer and signal generator functions. The tinySA does however use the same display, battery and housing as the nanoVNA-H
Question: Does the tinySA contain a Tracking Generator?
Answer: The generator function can not be used as a tracking generator as you can not use the spectrum analyzer and generator functions at the same time.
Question: Why is a wide scan with a low RWB so slow?
Answer: There are two factors that make the scan speed decrease. With a large span and a low RBW additional measurement points are inserted to avoid missing signals. Scanning 100MHz with a RBW of 10kHz requires 20000 measurements where using a 600kHz RBW would only use 290 measurements. The RBW filter is implemented in low sample rate DSP and the filter needs time to charge where the charging time is inverse proportional with the RBW. a 3kHz RBW requires more then 7 milliseconds measurement time per measurement point where a 600kHz RBW only requires 0.3 milliseconds.
Question: HELP, my tinySA crashes at startup with a stack dump or hangs
Answer: Open the case, unplug the battery, count to 10, reconnect the battery, close case.
Question: How are the additional inserted measurements consolidated into one displayed measurement?
Answer: The displayed measurement is the maximum of all the additional measurements to ensure the level of a signal falling within only one measurement is correctly displayed.
Question: Am I limited to maximum 290 or 450 scan points?
Answer: In standalone operation the scan can use many measurement points with a large span and low RBW but the display is always using maximum 290 or 450 points. When using the tinySA in combination with a PC the amount of points is unlimited. The Windows control program supports scanning with up to 30000 measurement points.
Question: In zero span mode there is a weird modulation visible, even when I apply a constant level input signal
Answer: When the input signal is very close to the zero span center frequency some yet unexplained interference occurs causing +/- 1dB variations in detected level. This can be eliminated by offsetting the zero span center frequency with 1/4 RBW.
Question: Is the design of the tinySA public domain?
Answer: The tinySA schematic and PCB design are not public domain. The embedded software of the tinySA is FOSS (free and open source software) according to the GPL v3 and can be found at https://github.com/erikkaashoek/tinySA
Question: My signal was frequency X but the tinySA says it is Y?
Answer: The total scan range is divided in points with equally spaced frequencies. The tinySA uses these frequencies for the markers, even when using an RBW much smaller then the frequency step between the points. Furthermore the tinySA takes steps of at least a quarter of the active RBW so any frequency reported has an uncertainty of at least that amount.
Question: Self test 3,4, 7 and 10 fail. What can be wrong?
Answer: This is happening when the observed level of the calibration output is wong. Did you connect high and low connectors? Is the used SMA cable OK? Did a power level calibration fail? If so, redo the power level calibration and run the self test again.
Question: The Attenuator self test fails (test 10 and 12 in the latest FW). What can be wrong?
Answer: This could be caused by a faulty attenuator. Here you can find how to check the attenuator

tinySA Ultra questions

Question: The tinySA Ultra hangs or crashes with a stack dump
Answer: Switch off, push jog button to the side and switch on again. Do a CONFIG/MORE/CLEAR CONFIG 1234 and restart without pushing the jog button to the side.
Question: The tinySA Ultra is does not react to touch commands or the jog button
Answer: The LCD cable may not be seated correctly. Open the case and carefully lift the black clip holding the LCD cable at both edges till it swings up. Reseat the cable and press the black clip down till it clicks in position.
Question: I'm not able to use touch for menu selection and I can not activate the touch calibration
Answer: Use the jog button to activate the menu and left/right/down of the jog button to select the menu option. If the touch calibration keeps failing loosen the screws of the shell a bit to reduce the pressure of the front of the shell on the touch the screen.
Question: Why is the zero span mode of the tinySA Ultra slower then the tinySA?
Answer: The tinySA Ultra uses a different component to enable small RBW but has the disadvantage of being slower.
Question: The LNA is not working. Where can I find a new LNA?
Answer: The LNA is U14, type number BGA2817, available from many suppliers
Question: The input switch is blown. Where can I find a new switch?
Answer: The input switch is U22, type number XA17-G4K.
Question: The screen is frozen and neither touch nor the jog button works, what to do?
Answer: Slowly loosen the 4 case screws at the back till the screen becomes responsive.

tinySA Basic questions

Question: I'm not able to use touch for menu selection and I can not activate the touch calibration
Answer: Use the jog button to activate the menu and left/right/down of the jog button to select the menu option. If the touch calibration keeps failing loosen the screws of the shell a bit to reduce the pressure of the front of the shell on the touch the screen.
Question: Why do the low and high input modes perform so different?
Answer: The low input mode has an input attenuator to avoid overloading and a good band pass filter to eliminate mirrors. The high input mode is a "for free" feature and we decided to make it available as, even with its limited performance, it could be useful.
Question: Can I inspect the SSB modulation of my transmitter?
Answer: As the minimum RBW is 2.7kHz it is impossible to look at details inside a 2.7kHz wide SSB signal. With careful setup it is just possible to check the alternate side band rejection or see the carrier rejection.
Question: Why does my signal have some unexpected weird side lobes when I zoom in?
Answer: The implementation of the resolution filters suffers from some spectral leakage due to the chosen DSP implementation.
Question: Why can't I do a screen capture of the version screen?
Answer: As long as the tinySA is in a busy wait in the UI there is insufficient memory for the execution of screen captures.
Question: How can I get a new rocker switch/internal switch/attenuator?
Anwer: These are available in single piece quantities with Mouser and other component vendors. The rocker is compatible with PL3-AC-V-T/R, the internal switch (U8 for low and U6 for high) is compatible with AS179-92LF and the attenuator (U9) is compatible with a PE4312C-Z
Question: In zero span mode there are weird spikes visible in my AM modulated signal
Answer: The AGC used to extend the dynamic range of the power detector has difficulty to react to very fast level changes, as a consequence the power detector may show deviations from the actual input signal. To test if this is happening one can disable the AGC in CONFIG/EXPERT CONFIG/MORE/AGC.
Question: Even without anything connected I still see some signals
Answer: The shielding of both the high and low input can not prevent strong transmitters from entering. A nearby FM, DAB, TV or mobile phone transmitter can be visible. In high input mode the harmonics of the 30MHz TCXO generating the clock frequencies are visible over the full frequency range at or below -95dBm. The low input is susceptible to the harmonics of the 48MHz MCU clock. When doing a 0-350MHz scan with an RBW of 10kHz these are clearly visible. The latest FW version effectively eliminates these MCU clock harmonics.

Question: I'm trying to measure AM modulation but the measurement seems completely wrong. What can be done?
Answer: When measuring AM modulation you have to carefully adjust some settings otherwise the measurement will fail. More info available in the page on measuring AM modulation
Question: Is there an Android App for the tinySA?
Answer: Not yet, but once there is sufficient free time I will have a look.
Question: Does my tinySA have ESD protection diodes
Answer: Make sure you have FW v1.3-3 or later. Go to CONFIG/VERSION. If the last line of the displayed version info is "ESD protected" the diodes are installed.
Question: After calibration the CAL output level at 30MHz reads a bit low, is this a problem
Answer: On some tinySA the CAL output level at 30MHz after calibration is measured a bit on the low side, levels down to -27.2dBm are not a problem given the nominal level of -26dBm.