Config Tab

Switching the tab to Config allows the user to modify the relevant initialization parameters according to local conditions. This parameter also determines the default settings that Web-888 SDR presents to the user when a new connection is passed in.

For normal users, the following values can be changed.

Frequency (kHz): initial frequency
Mode: Broadcast mode (AM, SSB, CW, etc.)
Colormap: color scheme of the spectrum map (set according to your preference)
Max receiver frequency: the frequency range received by the Web-888 SDR (up to 62 MHz)
ITU region: ITU region (according to the user's country)
Initial AM BCB channel spacing: Medium wave step unit (9 kHz, 10 kHz)

Status LED brightness

Change the brightness of LED

CAT interface baud rate

If you plug a USB serial adapter and use it for CAT control, this setting enable this UART to report the frequency tuning. default setting is disabled.

Allow RF attenuator switching by:

This setting controlls who is able to change the attenuator in the user UI. By default only allow local connections.

External Reference clock?

Turn on this option when you want to use external 10M reference clock input from EXT-CLK port. By default, it is off. Web-888 uses internal TCXO 24.768Mhz as reference clock.

External output clock frequency (enter in Hz)

Input a number to ask Web-888 to output a clock at the input frequency to EXT-CLK port. By default, it is 0 means not use this feature.

Warning

Above two functions cannot use at the same time as they are both using EXT-CLK port.

GPS correction of ADC clock

This controls how frequently the PPS signal to calibrate ADC Clock frequency. This only changes what DSP's parameter about the ADC clock rate. It will not physically change the clock frequency as the feature of "Correct ADC Clock by GPS PPS". By default, it is continues. Some long period of signals like WSPR and FST4W needs change this setting to much slow frequency.

ADC Dither

ADC dithering in the context of an analog-to-digital converter (ADC) is a technique where noise is intentionally added to the input signal before it is digitized. This might sound counterintuitive, but it actually helps improve the performance of the ADC by reducing quantization errors and distortion. Here are the key benefits of ADC dithering:

Improved Quantization: By adding noise, dithering breaks the correlation between the quantization error and the input signal, resulting in a more accurate digital representation.
Enhanced Linearity: It helps in randomizing differential non-linearity (DNL) errors, improving the overall linearity of the ADC.
Increased Resolution: For slowly varying signals, dithering can effectively increase the resolution through averaging. In essence, dithering helps in achieving a more precise and higher-quality digital signal by mitigating the limitations of the ADC's quantization process.

Default is OFF due to turn on this will incrase the noise floor.

ADC PGA

An ADC PGA (Analog-to-Digital Converter with Programmable Gain Amplifier) is a combination of an analog-to-digital converter (ADC) and a programmable gain amplifier (PGA). The PGA amplifies low-level signals before they are digitized by the ADC, enhancing the dynamic range and accuracy of the measurements. Here are the key benefits of an ADC with PGA:

Increased Dynamic Range: The PGA amplifies weak signals, allowing the ADC to better distinguish small changes in the signal.
Flexibility: The programmable gain amplifier allows for different levels of amplification based on the application's needs.
Improved Accuracy: Amplifying the signal before digitization reduces the impact of noise and quantization errors.

Default is OFF due to turn on this will incrase the noise floor.

Correct ADC Clock by GPS PPS?

Enable this option will use PPS signal from GPS to correct ADC Clock via tuning Si5351. It will make sure ADC clock is very close the desired frequency. However it will introduce some jitter to the clock, which impact ADC performance. The deault is OFF.