Host ID: 271
Just some rambling about HPR and that you should record a show!The world's going down, the HPR queue is low. Be one of the saviours, RECORD A SHOW! Whatever topic, you are not alone. Feel free to seek help, if you can't do on your own. One will have to struggle, to find a friendlier crowd with that wide range coverage from the simplest to "clouds". From toy to high tech and from jokes to wise words. Embracing you all. - Not just the nerds. It's not a "service", HPR is WE! So contribute the stuff, you'd like more of to see. If YOU like it, others surely too will. Diversity defines the realm, we are aiming to fill. Sure, there are heroes, lifting most of the weight. But we all are the foundation, deciding HPR's fate. Be thankful, you slackers, who leave those free slots, for those few prolific, still filling the spots. Please don't keep the burden on shoulders so few. Chime in with some topic, by sharing your view. High praise to those, stepping in a first time! We need more of you though, to strengthen the lines. Like an episode? - Please let us know! It's positive feed back, that's keeping us go. Comment on the page or record a reply. There's no reason for hiding or being overly shy. It's a community effort to make the thing we love stay. Because failing would mean, that HPR goes away. But it takes more than bad times to make HPR disappear! Together we stand, and we all are still here. Bit by bit, sharing knowledge and fun, building the confidence that HPR WILL go on. It's up to us, so just pick up the ball and keep the show rolling, for the sake of us all.
In this episode I simply let you participate with me replacing an electrolytic capacitor in the power supply of an Ethernet switch.
The broken capacitor shows a bulge in its housing and was therefore easily identifiable. The supply voltage in the fault condition could be observed with an oscilloscope to completely collapse when load is turned on. Both facts are illustrated in the image below.
Replacing the capacitor fixed the switch and brought it back in service.
Link to the videos of the crawling robots: http://iki.hs-weingarten.de/?lang=eng&page=p_crawler
Link to the general Ravensburg-Weingarten University of Applied Sciences page, where you can also find videos of the service robots "Kate" and "Marvin": http://iki.hs-weingarten.de/?lang=eng&page=aktuelles
This Episode is kind of a direct response to HPR1343 by Laindir, where he explains his awesome way to decode the morse code in HPR1216. For the fun of it, I start right out by digressing into a memory of mine. It is about how I tried to decode morse code telemetry from the AO-21 amateur radio satellite some 20 years ago by using a CBM-8032 computer.
After that I reveal the easy way to decode HPR1216 by using the CW mode of the program FLDIGI. Along the way, I mention the use of "monitors" in pulse audio, which are selectable in pavucontrol as input sources for audio applications. This is an easy way to loop back sound output from other applications. This method also combines nicely with WEBSDR, web accessible software defined receivers, all over the world. These may be used if you want to throw some real world signals at FLDIGI to play with the different modes. For listening to amateur radio communication I recommend to start out with one of these modes: CW (morse telegraphy), PSK > BPSK31 (very common, narrow band tele type mode) and RTTY > RTTY-45 ("original" radio tele type). For the typing modes you might want to check also "View>Waterfall>Docked scope" or activate "View>View/Hide Channels".
Finally I add a tip about using OSS-wrappers like aoss, from alsa-oss, and padsp from the pulseaudio-utils package, to run old OSS applications. I use this primarily for siggen, a suit of command line / curses applications for generating audio signals like sine wave, rectangle and so on.
NOTE: There is one stumbling block with pavucontrol, which I forgot to mention in the recording. Applications will only show up as playback sources or recording sinks when they actively use the interface. That is, the alsa player source will only be visible while playing, in the same way as an audacity sink can only be seen while the recording is going on.
- hpr1343 :: Too Clever For Your Own Good http://hackerpublicradio.org/eps.php?id=1343
- hpr1216 :: Digital Data Transfer http://hackerpublicradio.org/eps.php?id=1216
- Some sparse info on the AO-21 satellite http://www.sat-net.com/winorbit/help/satao21.html
- Wiki page covering the CBM8032 http://en.wikipedia.org/wiki/Commodore_PET
- Fldigi home page http://www.w1hkj.com/Fldigi.html
- WEBSDR main page http://websdr.org