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Rack is limited to 30cm deep due to closet dimensions. All three
server cases have been modded in one way or another (most drastic was
the DVR, cut down from 40cm deep with an angle-grinder). To save money /
energy, the DVR is the only one always on, except in winter when I can
justify the others heating the apartment.
The (fairly obsolete) Cisco Router and old WiFi broadband router
together can provide a Wireless LAN filtered with an IP deny list.
The Conference for Creative Use of the Radio Spectrum in Open
Systems, that brings users of the radio spectrum together. For over a
century, technology has made it possible to transfer more data, faster,
further. Today, wireless technology is everywhere and commonplace.
However, it remains a playground and a ground for innovation for many
communities. The spectrum24 conference provides an opportunity to
publicize projects and to allow the different communities that use the
spectrum to meet in person over a weekend.
M17 is a community of open source developers and radio
enthusiasts. We're building understandable systems in support of the
hackers and experimenters' history of ham radio.
OpenRTX is "Free and Open Source
Firmware for Digital Ham Radios. Top-down designed with modularity,
flexibility and performance in mind." The code is available on
github.
RF Swift
We next caught up with Sebastien
Dudek who had just presented a talk about the project
Introducing our Go and shell script-based toolbox, designed
to streamline the deployment of Docker containers for your preferred RF
tools. This evolving toolkit promises even more features in the near
future, making it an essential asset for RF enthusiasts.
VLF receivers design
The say that in Space no one can hear you scream, but here at
spectrum24 I'm not so sure.
What do you do when you're not organizing conferences ? Hacking a
project to contrail radios, and a lot more besides, using Linux.
trx-control is a modern and extensible software system for
Linux to control transceivers and other devices over the network. It can
as well be used to integrate third-party applications or databases.
The Conference for Creative Use of the Radio Spectrum in Open
Systems, that brings users of the radio spectrum together. For over a
century, technology has made it possible to transfer more data, faster,
further. Today, wireless technology is everywhere and commonplace.
However, it remains a playground and a ground for innovation for many
communities. The spectrum24 conference provides an opportunity to
publicize projects and to allow the different communities that use the
spectrum to meet in person over a weekend.
The IARU represents the interests of the Amateur Radio Service
worldwide to relevant international organisations, promoting the
interests of amateur radio and seeking to protect and enhance its
spectrum privileges.
Radioastronomy
activity with the Paris radio-telescope and EME
Setting
up an Amateur Radio Station at a Technical School
Anthony Le Cren - F4GOH,
teaches electronics and computer technology at a Technical School and
tells us about the science projects they got up to. He also managed to
get a hour a week where he and his students set up an Amateur Radio
Station in the school. What can you do in a hour a week ? Turns out
quite a lot.
Have a look at his site
Projets radio for more
information.
MeshCom is a project to exchange text messages via LORA radio
modules. The primary goal is to realize networked off-grid messaging
with low power and low cost hardware.
The technical approach is based on the use of LORA radio modules
which transmit messages, positions, measured values, telecontrol and
much more with low transmission power over long distances. MeshCom
modules can be combined to form a mesh network, but can also be
connected to a message network via MeshCom gateways, which are ideally
connected via HAMNET. This enables MeshCom radio networks, which are not
connected to each other via radio, to communicate with each other.
SatDump is a general purpose satellite data processing
software. It is a one-stop-shop that provides all the necessary stages
to get from the satellite transmission to actual products
Picture 1
shows a top down view of the radio. The large black square section
located at the front left of the picture contains the speaker left and
control board right. With the top cover fitted the control board is
accessible via s sliding cover. Both the speaker and control board need
to be removed in order to get access to the PLL backup battery. Both
come out as one piece.
Picture 2
shows the first three connectors that need removing from the control
board. All six connectors need removing before lifting the control board
and speaker.
Picture 3
shows the second three connectors that need removing from the control
board. Notice they are marked with the letter F.
Picture 4
shows one of the connectors removed. I was nervous removing these.
Fortunately I was able to remove them without causing any damage.
Picture 5
shows the speaker and control board lifted out of place and swiveled to
the side to reveal the PLL unit which is encased in a metal box for
screening. There are eight screws on the top lid that need removing to
gain access to the inside of the screened PLL unit.
Picture 6
shows the top cover removed from the screened PLL unit revealing the
backup battery located in the middle of the picture (Silver disc with
orange outer rim). The top cover is swiveled to the left hand side out
of the way.
Picture 7
shows a close up of the PLL backup battery. From the picture droplets of
liquid can clearly be seen on the right hand connecting terminal
indicating that the battery is leaking and must be removed before damage
occurs. On the right hand side of the picture notice the two connectors
attached to the circuit board that are terminated with unused sockets. I
have no idea what these sockets are used for. There are brass pillars
either side of the connectors. I assume some sort of add on board could
be purchased and perhaps this is what the unused connectors are for. I
also mention an unpopulated IC socket that can be seen in the top left
hand side of the picture. This is probably for another optional
extra.
Hi. I'm here to talk about Plain Text Programs, what they are, what
they do, why they're good, and why they're not for everything. Right up
front I'm requesting feedback on what I have to say. I'm on Mastodon and
I'll start a thread for each podcast or you can reach me by email.
In the future I plan on doing podcasts on specific Plain Text
Programs, some that I wrote and some that were written by others. Any
program that I will discuss will be licensed with a free culture
license.
The first thing I want to emphasize about Plain Text Programs is that
there's no database like SQL or LLM. All text data is written in plain
text files stored on a file system.
Now, I love databases. Before I retired I was a database programmer.
And as a database programmer I learned a lot about the difficulties
maintaining programs that rely on databases. There's a lot of cool stuff
you can do with a database that's just not reasonable to try with plain
text. Now that I'm retired I don't really want to work that hard
anymore. I want programming to be easy and fun.
Plain text does not mean there can't be images or other media. Image
files like .jpg or .png can be stored in the file system just like text
files. No worries.
A big advantage of Plain Text Programs is portability. To back up a
working program you copy the directory tree that holds the program's
files. To install or restore a Plain Text Program copy the tree onto a
system or server.
I usually work on Linux using the PHP programming language. This is
of course my preference. Any language running on any file system can be
used to write Plain Text Programs.
My minimum install will usually have a configuration file, at least
one program file, and a set of text files.
Some of the Plain Text Programs I use all the time that I wrote
are
Websites
Dirt Simple Photo Gallery
Plain Text Blog
Not Actually Plain Text Blog
Network With Hairy Larry
Internet Radio
MixRemix - Creative Commons Jazz
KGPL
Utilities
Backup The Web Server
I also use Plain Text Programs that other programmers wrote
So these are mostly websites or web applications but Plain Text
Programs do not have to be outward facing. They can just be an easy
program that you write to automate a task that you have to do
periodically. Like my Backup The Web Server program that I wrote in
bash.
I write my Plain Text Programs websites so that updates and additions
are made with FTP. FTP is a well established secure way to transfer
files from your development system to your web server. Another good
option, particularly for static websites that are generated on the
development system and then mirrored up to the server, is rsync.
I believe that simplicity is the key. I have written complicated
Plain Text Programs including the social network writing game, Collab.
But I think a simple one page or few pages design fits the plain text
paradigm better.
Well, I'm going to call this a wrap for now. I plan on covering
specific Plain Text Programs in future podcasts and I may occasionally
step back and look at the big picture or discuss ideas and
specifications for future projects.
Thanks for listening. I appreciate all your comments.
You can find the plain text script with the link to the comment
thread and all other links at home.gamerplus.org, a Not Actually Plain
Text Blog.
This section describes the syntax of the various forms of shell
commands.
DEFINITIONS.
The following definitions are used throughout the rest of this
document.
blank A space or tab.
word A sequence of characters considered as a single unit by
the shell. Also known as a token.
name A word consisting only of alphanumeric characters and
underscores, and beginning with an alphabetic character or
an underscore. Also referred to as an identifier.
metacharacter
A character that, when unquoted, separates words. One of
the following:
| & ; ( ) < > space tab newline
control operator
A token that performs a control function. It is one of
the following symbols:
|| & && ; ;; ;& ;;& ( ) | |& <newline>
Lists.
A list is a sequence of one or more pipelines separated by one of
the operators ;, &, &&, or ||, and optionally terminated by one
of ;, &, or <newline>.
ARITHMETIC EVALUATION.
((expression))
- + unary minus and plus
* / % multiplication, division, remainder
+ - addition, subtraction
<= >= < >
comparison
== != equality and inequality
&& logical AND
|| logical OR
CONDITIONAL EXPRESSIONS.
[[ expression ]]
Return a status of 0 or 1 depending on the evaluation of the conditional expression.
-a file, True if file exists.
-d file, True if file exists and is a directory.
-f file, True if file exists and is a regular file.
PARAMETERS (Positional Parameters & Special Parameters).
A parameter is an entity that stores values.
EXPANSION.
race expansion, tilde expansion, parameter and variable
expansion, command substitution, arithmetic expansion, word
splitting, and pathname expansion.
JOB CONTROL.
Job control refers to the ability to selectively stop (suspend)
the execution of processes and continue (resume) their execution
at a later point.
Title: 'The Linux Command Line' License:creativecommons:
Attribution-NonCommercial-NoDerivs 3.0 Unported 'CC BY-NC-ND 3.0' Source(s): linuxcommand:
'The Linux Command Line: Fifth Internet Edition' by William
Shotts. archive:
'The Linux Command Line Fifth Internet Edition' by William Shotts.
Title: bash Linux manual page. License: Bash is Copyright (C) 1989-2022 by the Free
Software Foundation, Inc. Source(s): man7: bash(1) — Linux manual
page man7:
Linux manual pages: alphabetic list of all pages.