News archive March 2017 - Koos van den Hout

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2017-03-29 Going full duplex with amateur satellites, part 3 : metal cases 4 years ago
I was looking for a metal case to put the low(ish) noise amplifier in and maybe the RTL-SDR. The RTL-SDR should also be shielded from the amplifier and from the computer as both RTL-SDR and computer cause their own signals.

The first cheap source of metal cases I could think of was old cigar boxes. Altoid tins are not available here. So I asked someone who I know who smokes cigars who had a number of old metal cigar boxes. Next step, finding the way to get the right holes in the boxes for the SMA and BNC connectors, and for the USB connection to the computer. Ideal would be to lend / find a punch for those holes.

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2017-03-29 (Neat story by Wil Wheaton. I can fully understand his story. I had one teacher that I always disagreed...) 4 years ago
Google+Koos van den Hout : Neat story by Wil Wheaton. I can fully understand his story. I had one teacher that I always disagreed with, leading to lots of detention. Things only improved when my parents were able to convince him to just try less harder with me and give me some space.
2017-03-28 (There may be an overused stockphoto here...) 4 years ago
Google+Koos van den Hout : There may be an overused stockphoto here...
2017-03-27 Upgrading WSJT-X after hearing two words 4 years ago
Recently it seems radio noise levels on the HF bands have gone up again so I spend more time trying to make contacts in JT65 mode since that mode is more robust against noise than PSK31.

To do this I use the WSJT-X software under Ubuntu Linux. WSJT-X is written by Joe Taylor KJ1T. The Ubuntu hams packages had WSJT-X 1.1 and I frequently ran across the problem that it crashes when the Internet connection to pskreporter is impossible when sending spots. In my setup the Internet connection drops regularly when I'm active with JT65 or PSK31 so that was an annoyance. Logged as Ubuntu bug #1673040: wsjtx crashes when internet connection is interrupted.

But this weekend I was listening to Linux in the Ham Shack Episode #184 and in the presenters talking about re-installing a Linux system for amateur radio I heard two words: wsjtx ppa. As soon as possible I looked it up and found WSJTX General Availability Release PPA, followed the installation instructions and upgraded to WSJT-X 1.7.

The main improvement is that it decodes better so I may make further contacts. Sofar it hasn't crashed on an interrupted Internet connection.

I see one problem: it doesn't like talking to my radio via rigctld, giving an error. When I stop rigctld as started by Cqrlog and let WSJT-X control the radio directly via hamlib things work fine. And suddenly Cqrlog sees the QSO in progress and logs it when done.

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2017-03-27 Laatste stukje netwerkgroep/PCgg archief 4 years ago
Laatste beeld van de webcam op HCC dagen 2005.

2017-03-27 Meten en grafieken maken van Powerline Ethernet doorvoer 4 years ago
Uit de archieven omdat ik de server waar dit ooit op draaide wil herinstalleren voor andere projecten.

Bij de HCC PCgg netwerkgroep hadden we ooit een netwerk gebaseerd op PLC (powerline communicatie) waarbij ethernet over stroomdraden gaat. Daar heb ik ook scripts voor gebouwd om statistieken te verzamelen over de doorvoer. Op de locatie in Maarn was dat voor de verbinding naar buiten niet zo briljant, zie de rapporten in Bijeenkomst 20 maart 2010 - hcc!pc netwerkgroep.

Maar voordat ik de scripts weggooi die deze gegevens verzamelden en er grafiekjes van maakten nog even voor de eeuwigheid. Het testdlan script gaat uit van output van dlanlist als:
koos@metcalfe:~$ dlanlist eth0
Type    MAC address        Mbps TX/RX       Version/Product
local   00:0B:3B:5F:95:AB  ---.-- / ---.--  INT6000-MAC-3-3-3348-00-2764-20080808-FINAL-B devolo dLAN 200 AVplus [MT2165]
remote  00:0B:3B:6F:AE:90   73.50 / 112.88  INT6000-MAC-3-3-3348-00-2764-20080808-FINAL-B

  • testdlan vraag dlanlist van devolo voor de huidige snelheid van devolo interfaces op netwerkkaart(en)
  • graphdlan maak grafieken per dag
De opzet van de scripts was om altijd te draaien als de machine actief was en achteraf overzichten te hebben per dag activiteit (meestal zaterdagen van 10:00 tot 17:00).

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2017-03-26 Going full duplex with amateur satellites, part 2 : Installing Gqrx SDR software and the first tests 4 years ago
With the hardware available it's now time to test the first part of the software setup: whether I can have running software defined radio.

To (re)install Gqrx I followed the instructions at Install Gqrx SDR on Ubuntu Linux. The first 'sudo apt-get purge --auto-remove' steps removed a lot of software and the latter 'sudo apt-get install' steps added newer (or maybe the same) versions. But I was glad to do a full reinstall, I have had weird problems with gqrx versions before. The laptop on which I am doing this has had an install of gqrx before, but was upgraded from Ubuntu 14.04 LTS to Ubuntu 16.04 LTS in the mean time, so a clean reinstall seemed a good idea.

I plugged in the RTL-SDR stick and checked whether no drivers were installed, which was indeed still correct. The kernel messages:
[156490.915435] usb 2-2: new high-speed USB device number 7 using xhci_hcd
[156491.111136] usb 2-2: New USB device found, idVendor=0bda, idProduct=2838
[156491.111141] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[156491.111143] usb 2-2: Product: RTL2838UHIDIR
[156491.111145] usb 2-2: Manufacturer: Realtek
[156491.111147] usb 2-2: SerialNumber: 00000001
To make sure the drivers aren't loaded, I have a /etc/modprobe.d/local-blacklist.conf with:
blacklist dvb_usb_rtl28xxu
blacklist rtl2830
blacklist rtl2832
blacklist lirc_dev
To test it with the 'minimal' setup I started with just the RTL-SDR and a simple antenna, and Gqrx. Enabled remote control in Gqrx and added a radio 'gqrx-sdr' in Gpredict with host 'localhost' and port '7356' (default for gqrx remote control) and Radio type 'RX only', PTT status 'none'.

Gqrx controlled by gpredict
Gqrx controlled by Gpredict, tracking a satellite
Now I can select this radio as '1. Device' in the 'Gpredict Radio Control' window, and select 'Engage' when the right satellite, transponder and 'Track' are selected, after which Gqrx nicely follows the frequency Gpredict has calculated.

No signal yet as I am testing this indoors with the small default antenna that came with the RTL-SDR stick. That will not pick up weak signals!

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2017-03-26 Going full-duplex with amateur satellites, part 1: introduction and I bought the hardware 4 years ago
I still want to get active on amateur satellites again, but the main reason is that the amount of work per contact is a lot more than for example in a digimode contest. But I still want to make those 'special' contacts, especially when the amount of local radio noise on HF is bothering me.

One of the most important improvements in making contacts on amateur satellites is working 'full duplex', meaning receiving signals while transmitting. The expensive way to reach that goal is buying a second amateur radio capable of receiving in FM and SSB modes in the 2 meter and 70 centimeter amateur bands and having computer aided tuning so gpredict can control the receiving frequency.

The less expensive way to reach that goal is using software defined radio. The good news is that Gqrx SDR can be controlled by other software which as the page shows is intended for remote control by Gpredict. All I needed now was reception hardware. Since the first RTL-SDR device I bought is always in use for receiving ADS-B signals from airplanes I decided to buy another cheap one to get me started. So it was on the shopping list for a recent visit to a hamfest.

At the hamfest I found a RTL-SDR stick with mcx connector and an mcx to bnc cable. But the same guy also sold cheap low(ish) noise amplifiers with SMA connectors and a 9V battery connector for power. So at one of the booths selling cable assemblies I found an mcx to male sma cable and a female sma to bnc cable, and a male to male sma cable.

The plan is to put this all together in some metal case to shield the lna from the outside world. Maybe also shield the amplifier from the RTL-SDR stick so it won't pick up any extra noise.

Should this work it would be possible to think of an upgrade with better SDR hardware and/or a pre-amplifier at the antenna side.
RTL-SDR stick and BNC cable - KvdHout on FlickrRTL-SDR stick and BNC cable
LNA and extra cables - KvdHout on FlickrLNA and extra cables
Read the rest of Going full-duplex with amateur satellites, part 1: introduction and I bought the hardware

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2017-03-26 It was Groundhog day again! 4 years ago
I have Gooogle Sightseeing on my 'regular visit' list because they found really interesting places all over the world and I liked to make a virtual visit to those places myself.

But lately the site hasn't been updated much and now I notice it has three 'Groundhog day' articles on the front page: Groundhog Day for 2017, Groundhog Day for 2016 and Groundhog Day for 2015. The last non-Groundhog Day article is from May 2015.

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2017-03-25 Gajim without automatic emoticons 4 years ago
For some circles I am active in the chat system of choice is jabber because it can be setup to demand encrypted links and has a nice array of client software which can deal with one client replacing the connection of another.

So I found gajim as client software for linux. But gajim has the habit of automatically changing text emoticons to images. I don't like that, if someone types (bf888) I want to see that and not have the last 8) replaced by an image of an emoticon with glasses.

Searching for a solution found Emoticons - Wiki gajim/gajim which states:
You are free, however, to disable emoticons completely, if you find them disturbing.
But no information on how to disable them all. I found in the advanced settings the option emoticons_theme which points at subdirs of /usr/share/gajim/data/emoticons in my installation (ubuntu). So I created a directory none with none/ containing:
# coding=utf-8
emoticons = {
        'doesnotexist.png': ['fDpK6OGDFCCLmq5MNjihfpjZuLontjkWp5XG5V7wTIAVXwaJ'],
Leaving the list empty with just {} gave an error. My python knowledge is nonexistant so I took this shortcut.

And now a :-) stays a :-) as I wanted.

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2017-03-21 Enigmail KEYEXPIRED / SIGEXPIRED error messages 4 years ago
PGP lock logo I was plagued by thunderbird/enigmail in one installation not wanting to send PGP-encrypted messages. It took me a while to debug because I seemed to be the first one to come across it. The error messages are not very helpful with a lot of SIGEXPIRED in them followed by a KEYEXPIRED. I found someone with probably the same problem at Enigmail stopped working: KEYEXPIRED/SIGEXPIRED - Super User but no usable answer at that time.

Searching further found me [Enigmail] enigmail won't let me encrypt messages anymore which does show another problem with old keys in the further thread. I started removing old keys showing with '00 00 00' fingerprints until I found my old 'home' key in the ring (0x2C663B5DF0D7C263). After that the error message changed to the key being unavailable. I dug through ~/.gnupgp/gpg.conf looking for mentions, and found:
#default-key F0D7C263
already disabled, and:
encrypt-to F0D7C263
when I changed that last one to a newer and better fitting key the problem was solved. There was a mention of F0D7C263 at the end of the enigmail error message but it was hard to draw conclusions about what it was doing there.

So as usual: good encryption is hard. And good error messages are hard too. I added a suggestion to the message so others may spend less time debugging this problem.

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2017-03-17 Soldeerstift vervangen van soldeerstation 4 years ago
Een tijd geleden heb ik een soldeerstation gekocht van Velleman, een Soldeerstation keramisch 48W VTSSC30. Die gebruik ik ook regelmatig naar alle tevredenheid.

Tot recent het steeds meer moeite ging kosten. De conclusie was uiteindelijk dat de stift aan het verslijten is, wat heel logisch is. Ik was even bang dat ik niet zomaar een losse stift kon krijgen, maar na dat ik deze gekocht had via Conrad blijkt die ook via Radio Centrum verkrijgbaar: Soldeerpunt 1,6mm Velleman VTSSC10/20/30/40 soldeerstation.

Stift vervangen, probleem opgelost. Grappig is dat volgens de Radio Centrum website de originele meegeleverde stift 1.6mm is terwijl ik in het overzicht van Velleman soldeerstiften bij Radio Centrum zie dat ik de 2mm versie had. Misschien moet ik nog eens een 0.8mm punt er bij kopen voor klein soldeerwerk.

Update: Radio Centrum zit dicht bij de winkel waar ik koffie haal, dus ik kwam er langs en heb gelijk een 0.8mm punt aangeschaft. Gelukkig hebben we nog een echte electronica winkel in Utrecht.

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2017-03-15 Eenrichtingscommunicatie op 3500 MHz 4 years ago
In een artikel in de Volkskrant vandaag KPN: introductie 5G bemoeilijkt door inlichtingendiensten - Volkskrant met daarin:
Het ministerie van Economische Zaken (EZ) biedt telecombedrijven in een recente beleidsnota aan andere frequentiebanden te veilen, omdat het voor de 3500 MHz-band vastzit aan een contract met het ministerie van Defensie tot aan 2026. De satellieten van de veiligheidsdiensten in het Friese Burum communiceren al jaren via deze hoge frequentie.
Volgens mij is dat helemaal niet "communiceren" maar alleen maar heel erg goed luisteren. In een eerdere zaak rond het gebruik van 3500 MHz kwam de nationale veiligheid ook voorbij, Enige wimax-provider in Nederland stopt ermee - Tweakers met daarin:
De reden voor het stoppen is dat Aerea zijn netwerk niet naar de noordelijke helft van Nederland mocht uitbreiden. Defensie wilde dat niet, omdat de 3,5GHz-frequentie het satellietgrondstation Station12, dat in handen is van Defensie, zou storen.
Met wat redeneren en nazoeken is wel te bedenken waar defensie/aivd/mivd zo graag naar wil luisteren: mobiele communicatie satellieten die in dat frequentiegebied signaal naar de aarde zenden.

Van tijd tot tijd lezen we verhalen over hoe vanuit Burum satelliet telefonie wordt afgeluisterd, zoals bijvoorbeeld Data uit Burum leiden naar piraten en terroristen - Een beetje uitzoeken levert op dat onder andere de diverse Paksat satellieten zoals Paksat-1 - Wikipedia English die allerlei communicatiediensten leveren op de C-band op frequenties vanaf 3500 MHz. Waaronder satelliet-telefonie. En Nederland ligt aan de rand van het gebied waar deze signalen nog (zwak) te ontvangen zijn: Paksat-1R coverage map - Satbeams.

Mijn conclusie is dat de 'communicatie' waar het over gaat het afluisteren van de downlink communicatie van onder andere de Paksat-1R is.

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2017-03-15 (Frequency coordination for satellites which want to use amateur frequencies goes via the IARU (International...) 4 years ago
Google+Koos van den Hout : Frequency coordination for satellites which want to use amateur frequencies goes via the IARU (International Amateur Radio Union) first before going to the regulator for the country the satellite operator works from. Documents and information via this page.

Giving this some signal boost because of some remarks on the Amsat North America mailing list.
2017-03-15 (In my opinion a good article explaining why an important website was taken off-line to make sure it ...) 4 years ago
Google+Koos van den Hout : In my opinion a good article explaining why an important website was taken off-line to make sure it was safe again before making it available again. More articles should explain computer security like this.
2017-03-12 (Remembering a wall which divided Germany and Europe. Museums received parts of the Berlin wall so we...) 4 years ago
Google+Koos van den Hout : Remembering a wall which divided Germany and Europe. Museums received parts of the Berlin wall so we can remember.

National military museum in Soesterberg on the old airfield.
2017-03-10 Keeping an eye on planes in the air 4 years ago
I usually keep dump1090 running on a raspberry pi. It seems it is quite easy to share the data from dump1090 with Plane Finder so I decided to give that a try.

With the installation instructions via the Share your data with Plane Finder page I had the software installed easily. But I needed to visit the configuration page of the software via IPv4... while I disabled IPv4 on the raspberry so it took some changes to make it work again. Next thing the software was reporting the data was available fine but not uploading to the Plane Finder server. Checking with strace shows that the software tries to upload via an IPv4-only connection which will not work. Temporary re-enabling IPv4 fixes things, so it's purely an IPv4/IPv6 thing.

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2017-03-10 Improving the Internet security one service at a time 4 years ago
At work we (indirectly) get the scanning results from Shadowserver which now includes open VNC servers which is yet another service we don't really want left open to the Internet in general. A few were found which are now actively chased after to get them firewalled/disabled.

I really like the concept of shadowserver. ISPs that want the information can get full overviews of insecure services and botnet activity on their network. A full overview of what shadowserver looks for can be found at The scannings will continue until the Internet improves - Shadowserver.

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2017-03-05 Back from a short holiday where I was active with amateur radio 4 years ago
We stayed in a holiday park in Germany for 6 days and I decided to bring radio, tuner and the 6-40m antenna. So I was DL/PE4KH for a week and operated PSK modes a few times.

In total I made 11 contacts. The 'radio environment' was about as noisy as I am used to at home so no improvement there. Disconnecting the power supply for the television and the cable modem in the bungalow helped a bit in reducing the radio noise.

The interesting part was on Thursday evening when I only heard noise on the 40 meter band and decided to give 80 meter a try. It was active with PSK signals, including from callsigns I recognize as regulars on 20 and 40 meter PSK. My best guess is that 40 meters was unavailable for others too! The interesting part was that the antenna tuner was able to tune the LW-10 antenna for 80 meter. I do guess a lot of power was lost in the tuner as I only was able to make contacts with stations that came in very strong for me.

For the next time:
  • Make sure fldigi on the laptop knows about all possible PSK and RTTY home frequencies, including those on bands I don't use a lot.
  • Both batteries I brought got depleted really quick when transmitting with 50 watts. I need more battery capacity.

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IPv6 check

Running test...
, reachable as PGP encrypted e-mail preferred. PGP key 5BA9 368B E6F3 34E4 local copy PGP key 5BA9 368B E6F3 34E4 via keyservers

Meningen zijn die van mezelf, wat ik schrijf is beschermd door auteursrecht. Sommige publicaties bevatten een expliciete vermelding dat ze ongevraagd gedeeld mogen worden.
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Other webprojects: Camp Wireless, wireless Internet access at campsites, The Virtual Bookcase, book reviews
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