HB3YAQLucerne
Your first reception in a browser
From choosing a web receiver to hearing a clear signal: frequency, mode, filter and audio, step by step.
Fundamentals2 min readReviewed 15/10/2026
HB3YAQ · Ajdin HadzicLearning to take awayhttps://hb3yaq.ch/en/knowledge/sdr-first-steps
View saved items →Only in this browser
WHAT YOU WILL LEARN
- Understand the reception path and its limits.
- Tune a signal systematically.
Try it in the simulated SDR learning lab →
Where the signal is received
With a web SDRIn a Software Defined Radio, software performs key signal-processing tasks such as filtering and demodulation. The analogue front end and converter still determine which signals can be processed.Example & full explanation →, a remote antenna receives the radio signal. Hardware digitises it and software prepares spectrum and audio for your browser. Your own location therefore does not determine which stations you hear. The receiver’s location, antenna and frequency coverage matter.
Start with a receiver that documents its location and covers the frequency range you want. Read its notes on use, antennas and available connections. A directory can help you find receivers, but does not guarantee a free connection or continuous reception.
↑ Back to contentsFive steps to a signal
Open the receiver interface and deliberately start audio. Begin at a moderate volume. Choose a frequency within the available range and the appropriate mode: AM for an AM broadcast station, for example, or SSB · USB / LSBSingle Sideband transmits one sideband, usually with the carrier suppressed. USB is the upper and LSB the lower sideband relative to the carrier reference.Example & full explanation → for a corresponding voice signal. A visible peak alone does not identify the required demodulation.
Select the signal in the WaterfallA waterfall shows a spectrum over time: one axis represents frequency, the other time. Colour represents relative signal level.Example & full explanation → and fine-tune it. Match the filter width to the wanted signal. Compare small adjustments one at a time: frequency first, then filter, then GainGain describes the ratio of output to input level. In a receiver it can occur before or after digitisation and is often expressed in dB.Example & full explanation →. This lets you identify what actually helps instead of changing several causes at once.
↑ Back to contentsWhen there is no audio
Check browser audio permission, volume, mute and any active SquelchSquelch mutes audio when its opening condition is not met. With level- or noise-based squelch, the threshold determines when audio becomes audible.Example & full explanation →. Then check the frequency range and mode. An overly narrow filter can cut speech; an unnecessarily wide one admits extra interference. With SSB, a small tuning error also changes voice pitch.
If reception remains unclear, compare a second documented receiver at the same time. Different results are an observation, not proof of a fault. Antennas, interference, propagation and internet connections can differ. Note the time, frequency, mode and receiver to make the comparison useful.
↑ Back to contentsExplore these relationships in the signal-path lab →
Need a term explained?
These explanations help you keep reading.
Got the idea?
You are in Lucerne listening through a receiver in another country. Which location determines the signals received?
Show answer & explanation
The location of the remote receiving antenna. Your browser handles controls and audio; it does not move the antenna to you.