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Antennas in Linux

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Linux

For this article, I want to introduce a piece of software I've actually used recently in my own work. My new day job involves studying the ionosphere using an instrument called an ionosonde. This device is basically a giant radio transmitter that bounces radio waves off the ionosphere to see its structure and composition. Obviously, an important part of this is knowing the radiation pattern of the various transmitters and receivers.

Several methods exist for modeling the electromagnetic fields around conductors, but here I'm covering one called NEC2 (Numerical Electromagnetics Code). It originally was developed in FORTRAN at the Lawrence Livermore National Laboratory in the 1970s. Since then, it's been re-implemented several times in various languages. Specifically, let's look at xnec2c. This package implements NEC2 in C, and it also provides a GTK front end for interacting with the core engine.

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Android Leftovers

Latest From Libinput

  • libinput and tablet proximity handling
    This is merely an update on the current status quo, if you read this post in a year's time some of the details may have changed libinput provides an API to handle graphics tablets, i.e. the tablets that are used by artists. The interface is based around tools, each of which can be in proximity at any time. "Proximity" simply means "in detectable range". libinput promises that any interaction is framed by a proximity in and proximity out event pair, but getting to this turned out to be complicated. libinput has seen a few changes recently here, so let's dig into those. Remember that proverb about seeing what goes into a sausage? Yeah, that.
  • libinput and the Dell Canvas Totem
    We're on the road to he^libinput 1.14 and last week I merged the Dell Canvas Totem support. "Wait, what?" I hear you ask, and "What is that?". Good question - but do pay attention to random press releases more. The Totem (Dell.com) is a round knob that can be placed on the Dell Canvas. Which itself is a pen and touch device, not unlike the Wacom Cintiq range if you're familiar with those (if not, there's always lmgtfy).
  • Libinput 1.14 Will Support Dell's Totem Input Device
    Dell announced the Totem two years ago while the Linux support is finally getting in order. However, there isn't yet any notable applications/tool-kits at least on Linux that support utilizing this specialized input device. Red Hat input expert Peter Hutterer, who also maintains libinput, has blogged about the Totem support addition for the upcoming libinput 1.14. If you are interested in this unique input device, Peter's post has all the interesting technical bits.

Jami/Ring, finally functioning peer to peer communication client

Some years ago, in 2016, I wrote for the first time about the Ring peer to peer messaging system. It would provide messaging without any central server coordinating the system and without requiring all users to register a phone number or own a mobile phone. Back then, I could not get it to work, and put it aside until it had seen more development. A few days ago I decided to give it another try, and am happy to report that this time I am able to not only send and receive messages, but also place audio and video calls. But only if UDP is not blocked into your network. The Ring system changed name earlier this year to Jami. I tried doing web search for 'ring' when I discovered it for the first time, and can only applaud this change as it is impossible to find something called Ring among the noise of other uses of that word. Now you can search for 'jami' and this client and the Jami system is the first hit at least on duckduckgo. Jami will by default encrypt messages as well as audio and video calls, and try to send them directly between the communicating parties if possible. If this proves impossible (for example if both ends are behind NAT), it will use a central SIP TURN server maintained by the Jami project. Jami can also be a normal SIP client. If the SIP server is unencrypted, the audio and video calls will also be unencrypted. This is as far as I know the only case where Jami will do anything without encryption. Read more

Codethink open sources part of onboarding process

Here at Codethink, we’ve recently focused our energy into enhancing the onboarding process we use for all new starters at the company. As we grow steadily in size, it’s important that we have a well-defined approach to both welcoming new employees into the company, and introducing them to the organization’s culture. As part of this overall onboarding effort, we’ve created How to Git going in FOSS: an introductory guide to the world of free and open source software (FOSS), and some of the common technologies, practices, and principles associated with free and open source software. This guide was initially aimed at work experience students and summer interns. However, the document is in fact equally applicable to anyone who is new to free and open source software, no matter their prior experience in software or IT in general. How to Git going in FOSS is hosted on GitLab and consists of several repositories, each designed to be a self-guided walk through. Read more