What's new in v.5.2.0- Show All — the station's other receivers under your waterfall. On a station with more than one receiver, a Show All checkbox after the receiver buttons puts each other receiver under the main waterfall as a live strip: its spectrum and waterfall, with its own markers and frequency scale, in its own colours and levels, the newest line at the top. Hover over it to read a frequency and the nearest marker; click and that receiver opens there, in the same tab — on a marker in the marker's mode. It is off until the listener ticks it, and costs about 10 KB/s per listener who does; each strip is a waterfall-only socket, so it is not counted as a listener on the other receiver, and the server needs no change. See docs/MULTI_RECEIVER.md.
- Back where you were. Leaving a receiver's page remembers its zoom, brightness, contrast, mode and frequency. Its strip on the other page opens on that same part of the band, with a green ▼ where you were tuned and a Full span / Last view button, and clicking inside that view brings the receiver back exactly so — not at its whole range.
- The right receiver by itself. A frequency this receiver does not cover but another of the station's receivers does — typed, from a link, a bookmark, a DX spot, the chat or another listener's label — opens that receiver's page, tuned there. The mouse wheel, the digit steps and a rig connected over CAT never switch receivers.
- A number pad, and a typed frequency brings its band. Click the black frequency box and a number pad opens (or type on the keyboard; the two Enter keys pick kHz or MHz); click a digit to step it up, right-click to step it down. A typed frequency now lands the way that band's button would: the waterfall zoomed to the whole band, the band's brightness and contrast, and the band-plan mode — on this receiver or, through the automatic switch, on the one that covers it. See docs/USER_GUIDE.md.
- Receive diversity switches even when only one site hears the station. Until the two streams are aligned they are paired by arrival, and the better site is chosen by SNR as usual — so a station heard only by the remote now comes through, the case where diversity helps most. The panel shows Ready (unaligned) meanwhile. See docs/RECEIVE_DIVERSITY.md.
- Connected Users and User Statistics per receiver. With several receivers open side by side in one browser, each page's windows show its own receiver, from its own logs.
- A bigger spectrum and waterfall on phones. In the extended mobile view the spectrum is 1.6× taller and the waterfall nearly twice as tall as before (on a 412-pixel screen 57 + 42 pixels instead of 35 + 23); the desktop page is unchanged.
- Fixes: the CW filter is centred on the 750 Hz tone (the tone used to sit 50 Hz from the filter's edge), and CW-L reaches the server as LSB; links written for KiwiSDR and UberSDR (modulation=CWU, CW-U, CWL) open in CW and CW-L; websdr.org registration works with sdr-list registration switched off, sends its ping over IPv4, and its callback (/~~orgstatus) now gets through proxy.py; the installers build the backend with OpenCL whenever the OpenCL step ran.
- Documentation: the User Guide, Several Receivers, Receive Diversity and Project Structure manuals cover all of the above in all seven languages, and the offline PDFs are rebuilt.
Download: https://github.com/sv1btl/PhantomSDR-Plus
Live Demo: https://phantomsdr.no-ip.org
Webpage: https://phantomsdr.psychomed.gr/index.html
Facebook Page: https://www.facebook.com/people/Phantomsdr-plus/61595163793205/
P.S. I would also like to publish it here, after many tries to minimize the latency
We measured the delay from the antenna to the listener's speaker on four web receivers at the same moment, each through its own web page. All four were tuned to the DCF77 time signal on 77.5 kHz, and every second mark heard was compared with an internet-synchronised clock.
Receiver Audio delay | Range over 3 minutes | LocationPhantomSDR-Plus (SV1BTL) 0.30 s 0.29–0.35 s Athens
UberSDR 0.30 s 0.21–0.31 s Athens
PA3FWM WebSDR (University of Twente) 0.35 s 0.31–0.44 s Enschede, Netherlands
KiwiSDR (Web-888) 0.96 s 0.96 s Athens
Measured on 15 October 2026 at 23:10 UTC over 180 seconds, all four at once from the same computer. The delay includes the network and the listener's sound output, and moves by a few hundredths of a second from one session to the next.
A full Video Tutorial of the version 5.2.0
Eric's (F1NSK) work, with a modification from me to adapt the PhantomSDR's waterfall colors.
Minor Update to v.5.2.1- An audio analyser. The **📊 Show** button in the Spectrogram section now opens a full audio analyser: the demodulated audio with a dB grid and peak hold, an axis that follows the mode (reversed in LSB), the recommended bandwidths and your current filter, and an RF view of the station in AM and FM. Under it, the station's occupied width with a within / wide / splatter verdict, and in USB/LSB an SSB audio report — tonal balance against Standard, DX or ESSB, compression, mains hum, residual carrier and opposite sideband — with a curve to compare before and after and a listening report to download and send. In AM and FM an AM/FM report takes its place — modulation depth and sideband balance, FM deviation and 99 % bandwidth, carrier offset, audio bandwidth, CTCSS tone and hum. No zoom is needed: while it is open the analyser keeps its own fine-detail view of the station. You can tune and change the mode from its header, and its colours show how far each part of the spectrum stands above the noise. A Mute button lets you analyse your own transmission without feeding it back into the microphone. Adapted from PhantomSDR-ORSAT by F1NSK. See **[docs/USER_GUIDE.md](docs/USER_GUIDE.md)**.
- Band buttons remember your frequency. Coming back to a band tunes the last frequency you used there, with the band's zoom, brightness and contrast as before; a second click on the active band button goes back to the band's default. A frequency link in the chat now frames its band the way **To Band** does. See **[docs/USER_GUIDE.md](docs/USER_GUIDE.md)**.
P.S. Please download and replace these files, and then recompile Backend and Fronend and restart. Because of the size, the zip does not include the documents, but you can download them from the repo.