Choosing the right filters for the mode you intend to operate on is crucial for optimising signal clarity and reducing interference. To change the filter bandwidth, press the BW button and turn the tuning knob.
Filters for FT8
When operating FT8, it’s recommended to set your filter bandwidth to 4 KHz. This wider setting allows the zBitx to pick up nearly double the number of signals compared to a traditional analog radio. Additionally, it removes the necessity of using SPLIT mode for transmitting or receiving at a greater offset from the base frequency.
Filters for USB/LSB
For USB/LSB, filters in the range of 1.8 KHz to 3 KHz work well. A 2.2 KHz filter is particularly effective for all voice modes, including LSB/USB.
Filters for CW and Digital Modes (RTTY and PSK31)
In the case of CW operation, both wide and narrow bandwidth filters can be utilised effectively.
When searching for CW signals, it’s advisable to use a wider filter. If you opt for a very narrow filter, such as 200 Hz, while scanning with a 1 KHz step size, you may miss many signals within the remaining 800 Hz of that skipped range. Therefore, using a broader filter while hunting for stations is generally a better approach.
Once you tuned into a signal, you can switch to a smaller tuning step size, ideally 10Hz, and select a narrower filter, around 400 Hz. Centering the signal within this bandwidth will improve audio quality and enhance decoding accuracy.