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Hosted by Ahuka on 2017-08-18 is flagged as Clean and released under a CC-BY-SA license.
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Health care is a service, and like all services it needs to be paid for one way or another. This means making choices, and there are consequences and implications to whichever choice you make. But there is no free lunch, you have to pay.
http://www.nirsoft.net/utils/usb_devices_view.html
This time only the two of us:
A lot of off the cuff technical explanation.
Starting from the comment by David Whitman to the last round table, we talk about frequency, wave length, propagation velocity and their relations. https://en.wikipedia.org/wiki/Wavelength. Approximate wave length values are commonly used to reference to entire "frequency bands", which are the frequency spectrum portions allocated to a certain radio service in proximity. Status of (amateur) frequency allocation may vary with band or country. They may not be "exclusive" and there can be "primary" and "secondary" radio services sharing that spectrum. Secondary services must not interfere with primary ones, while the other way round has to be accepted.
What frequency is most powerful? - It depends! We ramble a bit how different frequencies have different propagation depending on certain factors like daytime, time of year, sun spot cycle. - Please help out with more in depth information here! Join us. There is a varying maximum and a minimum useable frequency for ionospheric propagation. https://en.wikipedia.org/wiki/Maximum_usable_frequency
VHF (globally > 30MHz) and UHF (> 300 MHz) waves have a more line of sight propagation. Steve shortly introduces the concept of repeater stations. Usually at an exposed location, a repeater retransmits the signal that is received at another frequency, thus extending communication range. Participants only need to reach the repeater in order to be able communicate with each other. We hint at additional propagation modes for VHF, like sporadic E-layer propagation, but are not able to go into detail. - Please tell us, if you have experience in those fields!
Some thoughts about RF output power and how it is less important if conditions are right.
Modulation: Putting "information" onto a radio frequency signal. Staring out as a clean "carrier wave", its parameters are modified according to the modulation scheme. We start out and explain the basic concepts of amplitude modulation, AM, where the amplitude of the radio wave is altered by the modulating signal. Then frequency modulation, FM, where the modulation process influences frequency of the output signal. We use voice audio as an example as modulation content, but this can of course be of digital nature. SSB, single side band modulation. It is the standard voice modulation mode for short wave amateur communication. We give a very brief explanation of one possible way of generating it. We discuss how it is more efficient than AM in regard to occupied frequency spectrum use and transmit power.
This leads to ideas how great it would be if someone could record a show about those things, including audio examples. We further digress in how it may be a good idea to single out individual topics separate shows. The "rabbit holes" (tm MrX I think) we fall in while explaining other stuff. Make them available to be simply referenced in later shows and we can concentrate on the topic at hand.
There will be a place to put ideas and draw inspiration for shows here: https://etherpad.net/p/HPR-HAM-TOPICS
Next we pick up the discussion of frequency shift caused by the Doppler effect and its effect on satellite operation. This was triggered by a question in "hpr2216 :: Working AO-85 with my son" (http://hackerpublicradio.org/eps.php?id=2216). https://en.wikipedia.org/wiki/Doppler_effect
We ramble a bit how in the wide field of amateur radio no one can know everything right from the beginning. Take the jump start provided by the knowledge required for the test and go on with learning by doing.
How cool would it be to have shows from "Ham fests" like the "Dayton Hamvention", the "HAM RADIO" or any other event. A brief mention of the "ARRL Fieldday".
We have a mini poll and want to get feed back from the audience, if they would be interested to have some sort of decoding riddle in future shows.
get off the computer !
Hosted by Ken Fallon on 2017-08-14 is flagged as Explicit and released under a CC-BY-SA license.
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In this post I will show you how to take a default Raspbian Image and safely enable ssh by allowing remote access only with authorized keys.
Recently, and correctly, the official Rasbian Pixel distribution disabled ssh with the note that from now on SSH will be disabled by default on our images.To understand why this is a good thing please read A security update for raspbian pixel. In short, having 11 million computers out there in the hands of non security professionals, with a known username and password, is not a good idea.
That said there are many cases where you want to access your Pi remotely, and a key part of that is the ability to access it securely via ssh.
The Raspberry Pi site offers a solution for how to reactivate ssh. One option is via the GUI, Preferences > Interfaces> SSH > Enabled. Another is via the console sudo raspi-config > Interfacing Options > SSH > Yes > Ok > Finish. The third offers a more interesting option.
For headless setup, SSH can be enabled by placing a file named ssh, without any extension, onto the boot partition of the SD card. When the Pi boots, it looks for the ssh file. If it is found, SSH is enabled, and the file is deleted. The content of the file does not matter: it could contain text, or nothing at all.
This is exactly what we want. Normally you would burn the image, then boot it in a Pi with a keyboard, screen and mouse attached, and then add the file. A shortcut to that would be to burn the image, eject it, insert it again, mount the sdcard boot partition, and then create a file called ssh.
I don’t like either of these solutions as they involve varying amounts of user intervention. I want a solution that will automatically leave me with a modified image at the end without any intervention (aka human error) on my part.
So I want to build a script that can handle the following steps:
I could add to this list and customize every aspect of the image, but my experience has shown that the more you modify, the more maintenance you will need to do. When changes are made to the base Rasbian image, you will need to fix your scripts, and worse is the job of updating all those already deployed Pi’s.
A better approach is to use the base images and control them with automation tools like Ansible, chef, puppet, cfengine, etc. This allows the images to be treated as Cattle rather than Pets, to see what that means see Architectures for open and scalable clouds, by Randy Bias, VP Technology at EMC, Director at OpenStack Foundation.
Another approach to consider would be to Network Boot your Raspberry Pi and in that way the sdcard is barely used, and all traffic is run off the network. If you are deploying a lot of pi’s in a area with a good physical network then this is a great option as well. This has the advantage that all the files are kept on the network and can be completely controlled from a central location.
If you can’t be bothered to stick around and find out how I did it, you can download the script fix-ssh-on-pi.bash. Remember that it is intended more as inspiration rather than a working tool out of the box. I deliberately wrote it so you must edit it to make it fit your needs.
See the complete show notes for the step by step instructions that lead to the creation of the script file, with credit been given to the sites that offered each part of the solution.
https://wiiu.guide/ A complete guide to Wii U custom firmware, from stock to Coldboot Haxchi.
Hosted by Jon Kulp on 2017-08-10 is flagged as Clean and released under a CC-BY-SA license.
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Upon arriving at my parents' house tonight, I was struck anew by the incredible sounds of wildlife where they live in the woods. I decided to record and share with the HPR audience.
Hosted by Epicanis on 2017-08-09 is flagged as Clean and released under a CC-BY-SA license.
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Sorry this is such a short episode. I don't know what came over me, I was just listening to Mr.X talking about doing something with Python in Hacker Public Radio episode 2340, and for some reason I just felt a compulsion to record some kind of episode myself. It was so strange. I'm way behind on my Hacker Public Radio contribution duties anyway, so here's a quick, geeky tutorial about a thing I did with a Raspberry Pi just to try it.
The temperature sensor I'm using is one of the many "1-wire" protocol devices supported by established kernel drivers, hence the reference to loading the modules for it:
sudo modprobe w1-gpio
sudo modprobe w1-thermThe part about adding "dtoverlay=w1-gpio" to /boot/config.txt and then rebooting is also necessary, otherwise the modules load but no devices show up in /sys/bus/w1/devices/ .
Part of the fun was coming up with a way of extracting the temperature reading in useful form without having to write a bunch of unnecessary python code. Not that there's anything wrong with python, but I get the impression that some people think everything "RaspberryPi" has to be written in python. An example of this that amused me is the piFM project, which cleverly abuses the first-generation Raspberry Pi spread-spectrum circuitry to turn it into a surprisingly powerful FM radio transmitter. This project had two ways to run it - the actual compiled C program that takes input audio and makes FM radio come out...and a python "module" that was literally just a system call that...ran the C program that takes the audio and makes FM radio come out.
Examples of reading the temperature data that I ran into tended to also be short python scripts, so I took it as a challenge to do without, resulting in the fun-to-recite command in the episode, which on my system is:
echo "scale=3; (`grep -o "[[:digit:]]\{5\}" /sys/bus/w1/devices/28-05167380f6ff/w1_slave`/(5000/9))+32" | bcAs an example of what you get with a correctly connected and configured DS18B20 module on a Raspberry Pi, in my case the device shows up as:
/sys/bus/w1/devices/28-05167380f6ff/Your device's number after the "28-" will be different, so just replace my example with your own device's number.
If you read the "w1_slave" virtual-file in that directory, you get something that looks similar to this:
67 01 4b 46 7f ff 0c 10 c4 : crc=c4 YES
67 01 4b 46 7f ff 0c 10 c4 t=22437To be completely proper, one probably should validate that output to make sure the CRC matches so you know for sure that the read of the temperature data was correct, but I've had Zabbix checking my living-room temperature once every minute for a couple of days now and seen no odd readings or failures, so I'm not going to bother making anything more complicated than my hypnotic one-liner, unless I ever try to use the same kind of setup to monitor something more important, like a tank of expensive fish or a bioreactor full of beer.
If you want some more detailed connection instructions for the DS18B20 temperature sensor and the Raspberry Pi, here is one of the many online pages with the whole process:
https://learn.adafruit.com/adafruits-raspberry-pi-lesson-11-ds18b20-temperature-sensing/hardware
Hi Tony Hughes here with the 5th and final show of some short interviews I did during the Liverpool Makefest held on the 24th June 2017 at Liverpool Central Library.
The first interview is with Diane from Melt 3D printing
The second interview was with Michael from Electric Flapjack Guitars
https://lpoolmakefest.org/portfolio/electric-flapjack-guitars/
@EFGuitars
Hosted by HPR Volunteers on 2017-08-07 is flagged as Explicit and released under a CC-BY-SA license.
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Series: HPR Community News | Comments (1)
Welcome to our new host:
Ironic Sodium.
Policy decisions surrounding HPR are taken by the community as a whole. This discussion takes place on the Mail List which is open to all HPR listeners and contributors. The discussions are open and available in the archives run externally by Gmane (see below) and on the HPR server under Mailman.
Note: since the summer of 2016 Gmane has changed location and is currently being reestablished. At the moment the HPR archive is not available there.
The threaded discussions this month can be found here:
http://hackerpublicradio.org/pipermail/hpr_hackerpublicradio.org/2017-July/thread.htmlThese are comments which have been made during the past month, either to shows
released during the month or to past shows.
There are 23 comments in total.
There are 3 comments on 3 previous shows:
There are 20 comments on 8 of this month's shows:
In the past month we have had contributions from bjb and Windigo and I have added a few tags & summaries myself. Many thanks to all contributors.
See the current status and instructions for making your own contribution at "Shows without a summary and/or tags". This page has recently been reformatted for easier navigation and a new section has been added. This section lists the hosts whose shows need attention followed by the show numbers that need work.
Currently there are 957 shows which need summaries or tags to be added. All contributions to this project are most welcome.
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