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fl-moxgen

Designs Moxon rectangle antennas and prints them to scale

What it does

Computes the dimensions of a Moxon rectangle for a chosen frequency and wire diameter, draws it, and prints it to scale as a PDF -- a template you can lay wire against.

Why you would want it

A Moxon is a two-element beam with about 5 dB of gain and a very deep rearward null, made from wire and a couple of spreaders, and it is one of the best returns on effort in portable antenna building. Its dimensions are fussy: the gap between the tips sets the null and small errors move it a long way. This does that arithmetic and hands you a drawing rather than four numbers.

Before it will work

A desktop session and a frequency. Nothing else -- the design work happens before any hardware exists.

How it installs

  • source (make) from https://sourceforge.net/projects/flmoxgen/files/Fl_MoxGen-1.00.tar.gz/download
  • build dependencies: build-essential, pkg-config, libfltk1.3-dev, libhpdf-dev
  • Built in a Debian 13 container on 2026-08-28 with the two overrides above: make exits 0, fl_moxgen is produced, and running it headless gets as far as "Can't open display", which is a GUI binary working. AHRL bundles 1.01; SourceForge offers only 1.00 and no 1.01 exists there, so this pins what upstream actually publishes. Its install target copies to a hardcoded BINDIR=/usr/local/bin and SHAREDIR=/usr/local/share/fl_moxgen rather than reading PREFIX. That matches our default prefix and would silently ignore any other.

Binaries this produces:

  • fl_moxgen

Known problems

Check that you got the PDF-capable build. Without libharu found at build time the Makefile quietly builds fl_moxgen_no_pdf instead, which is the same program with the printing gone and no message saying so. The build arguments above prevent it, and it is worth knowing because printing to scale is most of the point. As with any modelled antenna, the numbers assume the thing is in free space; a Moxon two metres off the ground behaves differently and the null in particular will not be where the model says.

Keeping it current

  • probe: none
  • strategy: rebuild
  • SourceForge shows 1.00 current with 0.01 through 0.05 in Old_releases. Infrequent; check the project files list by hand.

Where to get help with the software itself

The flmoxgen project on SourceForge. The sha256 is ours, computed from the SourceForge download, since upstream publishes no checksum.

Source: catalog/packages/fl-moxgen.yaml