# Settings The **Settings** tab lets you customize the app's behavior to your preferences. ## Screen Orientation On default, the **AUTO** setting follows your system's behavior for screen orientation. If you'd like to lock in a fixed screen orientation choose one of the following from the dropdown list: - Portrait - Landscape - Reverse Portrait - Reverse Landscape ## App Color Theme This setting lets you choose the color theme of the app's controls. RF Analyzer has a standard theme but you may also choose the dynamic coloring of the Android System (available from Android Version 12): - RF Analyzer Theme (dark) - RF Analyzer Theme (light) - RF Analyzer Theme (system setting) - System Theme (dark) - System Theme (light) - System Theme (system setting) Selecting a 'system setting' theme will use the systems' current setting for the light/dark mode. Currently RF Analyzer looks best using the RF Analyzer (dark) theme which is the default setting. ## Font Size (FFT Plot) The font size setting affects the size of the labels and the grid in the FFT and Waterfall plot. ## Context Help System This setting enables or disables the context-aware help system. If enabled, a long press on any UI element **label** will open the user manual section for this UI element. The label is located in the upper left gap of the border of each UI element. ## Reverse Tuning Wheel This checkbox allows you to reverse the direction in which the tuning wheel moves the channel indicator. The default (disabled) is that a swipe to the left on the tuning wheel also moves the channel to the left (i.e. decreasing the frequency). However, a physical tuning wheel on an old radio did actually work the other way around which can be enabled with this setting. Choose which behavior feels better or more natural for you. ## Control Drawer Alignment (Landscape) The Control Drawer is accessible on the side of the screen when the device is in landscape orientation. This setting lets you choose on which side the drawer should appear. ## Low Performance Mode !!! warning "Enable only if necessary!" This mode is intended for old and less powerful devices. Only enable it if you have performance issues. This mode reduces the quality of the filters inside the demodulation path of the app. If your demodulated audio is stuttering or choppy, it might be because your Android device is not capable at running these filters at their intended quality. In this case, enable this setting and use the filter quality slider to reduce the filter quality until the audio is not choppy anymore. Note that with reduced filter quality you will hear more noise and more importantly: you will hear aliases (think of aliases as ghost signals: they are not visible in the FFT but you can hear them in the demodulation - they are only there because the filters are too weak). Currently, the only filter which is affected by this setting is the filter for the resampler. The resampler is used to downsample the signal from the sample rate of the SDR source (e.g. 2MHz for a RTL-SDR) to a lower sample rate for demodulation. If you enable [Show Debug Information](#show-debug-information) you can see the load of the resampler as percentage. If this load is greater or very close to 100%, your Android device is not able to run the filter at the necessary speed. The load on your phone increases if the input sample rate increases (e.g. with a HackRF you can go up to 20MHz) or if the number of filter taps increase. This setting reduces the filter taps to reduce the load. If possible you should rather reduce the input sample rate: This will give you better audio quality at the cost of seeing less bandwidth. ## Allow Out-of-Bound Frequency (RTL-SDR) The RTL-SDR devices have a tune frequency range which is determined by the tuner chip: | Tuner Chip | Lowest Frequency | Highest Frequency | |--------------------|------------------|-------------------| | Elonics E4000 | 52 MHz | 2200 MHz | | Rafael Micro R820T | 24 MHz | 1766 MHz | | Rafael Micro R828D | 24 MHz | 1766 MHz | | Fitipower FC0013 | 22 MHz | 1100 MHz | | Fitipower FC0012 | 22 MHz | 948.6 MHz | | FCI FC2580 | 146 MHz | 924 MHz | RF Analyzer is programmed to restrict the tune frequency according to the tuner chip that is currently used. If this is undesired, this setting allows you to disable these restrictions. That means any frequency can be entered. The result however, may be incorrect if the chip does not support the frequency. If you use a RTL-SDR Blog v4 dongle it is recommended to enable this setting. This will allow you to tune below the 24MHz which is usually the lowest frequency which the R828D tuner can tune. But the Blog v4 has an automatic upconverter build in which allows you to tune below this frequency. !!! warning This is an expert setting that should only be enabled if you know what you are doing. ## Show Debug Information With this switch enabled, debug information (e.g. current FPS) is printed in the upper right corner of the FFT plot. ## Logging For debugging purposes, the app can write all log messages to a text file. Once logging is enabled, the text file can be viewed, saved to a folder, shared or deleted. In case you encounter software errors in the app please consider giving me feedback via email (rfanalyzerapp -at- gmail.com) or via a [GitHub Issue](https://github.com/demantz/rfanalyzer/issues) and include the log file. In case the app crashes, please allow the Android System to collect data for a crash report. This is the most efficient way for me to be able to fix such issues. --- ## Wrapping Up This marks the end of the introduction to the RF Analyzer control drawer elements. Further information on the app (e.g. licensing and access to the manual/tutorial) can be found on the *About Tab*. If you are interested in further reading on signal processing and amateur radio you may head over to the [Additional Information](./advanced.md) section of this manual.