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glfer

QRSS and DFCW receiver for extremely slow narrowband CW on LF/MF

What it does

Receives and displays QRSS (very slow CW, seconds to minutes per element) and DFCW (dual-frequency CW) as a scrolling spectrogram, so signals far below the audible noise floor become visible.

Why you would want it

QRSS operating on the LF and MF bands uses milliwatts and relies on visual detection over long integration times. This is one of very few Linux tools that does it, and there is no maintained alternative.

Before it will work

A receiver with stable frequency reference and audio into the sound card. Frequency drift matters more than sensitivity for this mode.

How it installs

  • source (autotools) from https://www.qsl.net/in3otd/glfer-0.4.2.tar.gz
  • build dependencies: libgtk2.0-dev, libglib2.0-dev, libgdk-pixbuf-2.0-dev, fftw2
  • compiler flags: -Wno-incompatible-pointer-types, -Wno-deprecated-declarations, -Wno-implicit-function-declaration — without these it does not build on a current toolchain
  • Two of these build dependencies are themselves at risk: libgtk2.0-dev (see toolkit_risk — GTK2 is end-of-life with no port to move to) and fftw2, the 1998-era FFT library modern code left for fftw3. D-016: AHRL never checks exit status, so if either has already been dropped from a target the build fails silently there. Measured 2026-08-28: both still resolve on all five x86 targets — Debian 13 and Parrot fftw2 2.1.5-7+b1 / libgtk2.0-dev 2.24.33-7, Ubuntu 26.04 2.1.5-7build2 / 2.24.33-10, Kali 2.1.5-8 / 2.24.33-10+b1, Mint 22.3 2.1.5-6build2 / 2.24.33-4ubuntu1.1. The risk is real and it has not arrived; the register above stays, because the day it does arrive nothing will announce it. fftw2 is also still pulled by cassbeam in the same archive, which is part of why it survives.

Binaries this produces:

  • glfer

Known problems

Dates from 2003 and requires three warning suppressions to compile on a modern toolchain, all recorded in compiler_flags. Depends on GTK2 and FFTW 2, both of which are being retired by distributions; when a target drops either, glfer stops building there.

Toolkit risk

  • gtk2: no path, checked 2026-08-25 — GTK2 reached end of life and is being removed across distributions. glfer 0.4.2 dates from 2003 and has had no upstream release since; there is no GTK3 or GTK4 port to migrate to, so this is no_path rather than not-yet-ported. When a target drops libgtk2.0-dev, glfer stops building there and the correct response is a status change, not a patch.

Keeping it current

  • probe: none
  • strategy: manual
  • No upstream release since 0.4.2. Treat as finished software; check annually rather than expecting updates.

Source: catalog/packages/glfer.yaml