News archive February 2018 - Koos van den Hout

Archive by year: 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020

2018-02-19 Again new countries in amateur radio in a pair 2 years ago
This evening another two new countries in my amateur radio log: Lebanon and Gibraltar. First OD5ZF from Lebanon and 4 minutes later ZB3M from Gibraltar. That makes three pairs in two months.

These two were both in FT8 mode on the 40 meter band. FT8 is very good at fast contacts at low received signal levels.

Tags: , ,
2018-02-18 I learned event-based programming recently 2 years ago
On 8 and 9 February last week I attended the Surf Security and Privacy conference. SURFcert, the incident response team of SURF, had its own 'side event' within this conference, an escape room. Since the members of SURFcert like to visit escape rooms themselves, the idea was to build our own escape room. A simple one as teams of 2 or 3 people had to solve it within 15 minutes. The best scores were indeed just over 5 minutes so it was doable.

The escape room clock
The escape room clock
The theme of this escape room was the trip Snowden made: from the US to Hongkong to Moscow. Each location had a puzzle and like Snowden the only thing you could take to the next location was knowledge. In this case a 4-digit code to open a lock. Someone else in the SURFcert team did most of the hardware work and I decided to dive into some programming to support this effort. The escape room needed a countdown clock that could only be stopped by the right code. My idea was to use a barcode scanner to link the stop action to scanning the barcode on an object.

So I installed a Raspberry Pi with a raspbian desktop and found out how to set up the autorun on the Pi so my program would be started at startup when the user 'pi' logs in automatically. This was done by starting it from ~/.config/lxsession/LXDE-pi/autorun.

The program I wrote had three inputs:
  • A reset switch connected to GPIO pin 11 and ground
  • A start button connected to GPIO pin 03 and ground
  • Entering the right barcode to stop the time. In the end this was the barcode of a real Russian bottle of vodka, so my program needed vodka as input
For the barcodes I used an usb barcode scanner I have lying around. It behaves like a usb keyboard so scanning a barcode will cause the code to be entered as keystrokes with an enter key at the end,

But all programming I do is sequential. This is different, I needed to write an event-based program. It needs to react to time events, enter events and needs to check the state of gpio bits on time events. And on certain events it needs to change the global state (reset, running, stopped). The last time I did any event-based programming was an irc-bot written in Perl 4.

So with a lot of google searches, copypasting bits of code, searching a lot for which input bits would be default high and go low when connected to earth and a lot of trying I wrote a program. It uses WxPerl to have a graphical interface and use events. I'm not saying its a good program, but it did the job.

Notable things:
  • The OnInit function sets up everything: a window with minimal decorations, tries to set it full-screen, a text box that will show the time and starts at 15:00 as static text. A handler for time events that will be called 10 times per second. And an input box and a handler for when the enter key is pressed.
  • The onTimer function that looks at global state and decides which inputs are valid in that state and handles them
  • The onenter function that calculates a sha256 hash of the input line and checks which inputs can change the global state. The hash was to make sure that someone who could have a look at the source still had no idea what the commands were to control it all via keyboard. And no keyboard was connected anyway. The input for a shutdown is the barcode from one of the loyalty cards I carry around.
Read the rest of I learned event-based programming recently

Tags: ,
2018-02-18 Two new countries in the log and I participated in the Russian worldwide PSK contest 2018 2 years ago
Two new countries in the PE4KH log: Oman and India. Oman was Friday afternoon when I was home early and decided to turn the dial over the 40 meter band to make some phone contacts and heard A41CK call. Who took my call on the second try!

India was late Friday evening. The call VU2NKS showed up in FT8 and it had a direct pile-up (lots of people answering). But with some persistance from my side and good operating skills from the other side the contact was made.

And this weekend was the Russian Worldwide PSK Contest so I participated Saturday afternoon / evening and a bit Sunday right before 12:00 UTC. I managed to start Saturday 12:00 UTC sharp calling CQ. Which worked at that time for getting contacts. I chose the 40 meter band category because I expected most radio time this weekend would be after sunset.

In the end I made 64 contacts. Not a very high score, but I had times were several contacts happened in short succession so I am improving in digimode contesting.
Band  QSOs Dupes Points Mults
160      0     0      0     0
80       0     0      0     0
40      64     0    388    28
20       0     0      0     0
15       0     0      0     0
10       0     0      0     0
======================================
Total   64     0    388    28
Claimed score is 10864 points
Read the rest of Two new countries in the log and I participated in the Russian worldwide PSK contest 2018

Tags: , , ,
2018-02-11 Plotting the number of amateur radio contacts 2 years ago
After the end of January I decided to plot the number of contacts again. QSO count plot up to January 2018 January is a busy month with two contests for me but I did not make a lot of contacts outside of those contests this year. I added contacts from holidays and the PE4KH/P activities to the total count.

Some more work on the plot script, I think bars look better than a line graph. But you could spend hours in gnuplot making the plot just right...

The new script:
set output "qslcount.png"
set terminal png size 640,300 fontscale 0.7
set timefmt "%Y-%m"
set xlabel "Month"
set ylabel "Number of contacts"
set xdata time
set style fill solid
set xtics format "%b %Y"
set xtics rotate
set grid
set boxwidth 0.75 relative
set autoscale xfixmin
set autoscale xfixmax
plot "dataset-qsocount" using 1:2 title "Contacts/Month" with boxes
Update: And indeed the change in x autoscale was one bit more 'just right'. The first graph was in February 2017: Rising number of amateur radio contacts.

Tags: , , ,
2018-02-02 (Applying robot logic to the term 'wingman') 2 years ago
Google+Koos van den Hout : Applying robot logic to the term 'wingman'
2018-02-02 Trying to make me skip the rest of the security report 2 years ago
In the sshd logging today:
sshd[26961]: Invalid user <!-- from 103.9.88.249
But the logging is parsed via software that doesn't trust input either, so the rest is in the report too. Including more attempts from that IPv4 address.

Tags: ,
2018-02-01 TV plannen van 50 jaar geleden 2 years ago
Tekst over TV uit Februari 1958 Iedere maand verschijnt er een Electron van 50 jaar geleden op Electron 50 jaar geleden en daar kijk ik graag even in, om het 'nieuws' op amateurradio gebied van 50 jaar geleden te zien. In die van Februari 1958 viel me een stukje op onder het kopje "Televisie" met:
Voor onze lezers is het wellicht interresant, te weten dat Philips op Maandag het normale TV-programma relayeert in band V: beelddraaggolf 772,25 MHz, geluidsdraaggolf 777,75 MHz. Amateurexperimenten in deze band zijn van veel belang, want ondanks de ontvangstmoeilijkheden, die er nog zijn, kon het toch wel eens dé TV-band van de toekomst blijken te zijn. Een voordeel van deze band is natuurlijk in de eerste plaats het grote aantal beschikbare kanalen - de band loopt van 610-960 MHz! -. De commerciële televisie, die in ons land ook nog eens op gang hoopt te komen, vlast natuurlijk op een aantal kanalen in die band. Een ander voordeel is, dat de antennes zo klein kunnen zijn, hetgeen het stedenschoon ten goede zal komen.
Ondertussen is analoge TV opgekomen in de UHF band en weer gestaakt. Opvallend is voor mij ook dat de genoemde draaggolf frequenties niet uitgekomen zijn op latere UHF kanalen. De afstand van 5 MHz tussen de audio en video draaggolf klopt wel met de analoge TV op UHF standaarden van later.

Commerciële TV via de analoge etherkanalen is er nooit gekomen, dat is heel lang tegen gehouden en later via kabel/satelliet opgekomen en pas bij de digitalisering kwam er ruimte voor digitale TV via de ether. Het deel van de UHF band gereserveerd voor TV-kanalen is ook gekrompen, ondertussen zijn we aan het werken naar een einde bij 700 MHz.

Mooi om zo'n voorspelling te zien en te vergelijken met de huidige realiteit.

Tags: , , , ,


, reachable as koos+website@idefix.net. PGP encrypted e-mail preferred.

PGP key 5BA9 368B E6F3 34E4 local copy PGP key 5BA9 368B E6F3 34E4 via keyservers pgp key statistics for 0x5BA9368BE6F334E4 Koos van den Hout
RSS
Other webprojects: Camp Wireless, wireless Internet access at campsites, The Virtual Bookcase, book reviews
This page generated by $Id: morenews.cgi,v 1.46 2019/10/20 15:42:02 koos Exp $ in 0.015201 seconds.