PD4KH Amateur radio - Koos van den Hout

I passed my radio amateur exam in March 2013 and I registered the callsign PD4KH (pappa delta four kilo hotel!). PD4KH on qrz.com

I am located around maidenhead locator: JO22NC

For now this page contains just the 'hamradio' items from my homepage.


Amateur Satellites
D-Star digitale amateur radio (Nederlands)

2014-04-18 (#)
Another ISS pass and I was already aware the orbit may be changing a bit since gpredict and hamsatdroid were disagreeing on the time of the pass.

And indeed, the ISS pass started around the later time from gpredict. I heard the AFSK data clearly. The signal from the ISS is strong enough that I can receive it most of the pass with the arrow antenna just pointing directly up. Maybe I can use this to record an entire pass and decode the AFSK data.

I guess celestrak.com (used by gpredict by default) is better up to date than amsat.org (first option in hamsatdroid). Since hamsatdroid can also use the celestrak.com data I switched to this source. The fun part is that satellite names aren't the same. 'SO-50' according to amsat is 'SAUDISAT 1C (SO-50)' according to celestrak.

2014-04-18 (#)
A bit of searching later found the right incantation to make gnuplot adjust color based on a third value (signal level in my case). It isn't very complicated:
set size square
set angles degrees
set polar
set grid polar 30
set xtics axis 0,30
set ytics axis 0,30
unset border
unset param
set xrange[-90:90]
set yrange[-90:90]
set rrange[0:360]
set trange[0:90]

set title "GPS satellite tracks"
set xlabel "Azimuth"
set ylabel "Elevation"
set terminal png size 600,600
set output "gpsazelsig.png"
plot "gpsazelsig.dat" using 1:2:3 palette notitle
But the resulting plot isn't very helpful for my original question: in which direction radio signals are obstructed. There are some obstructions in the Southwest, but they are comparable to what is in the Northeast.

2014-04-16 (#)
I want to get an idea of the 'radio shadow' around our backyard to get a better idea of the minimum elevation to receive from and transmit to amateur radio satellites. Since there still is a gps receiver on the roof of the shed and the earlier ntp experiments aren't running at the moment I decided to stop ntp and log the $GPGSV GPS satellites in view messages from the gps unit. My idea is that the radio signals from GPS satellites get obstructed by houses at least the same as UHF signals, so a GPS satellite reception plot will be interesting. Something like the VisualGPS plot I made at a previous house with a different GPS unit. Note that the plotted satellite tracks are way outside the plotted contour which I recall was a nice approximation of the view during the test.

Now to get this data plotted with gnuplot in a polar plot. I found out the orientation of $GPGSV messages (true north is 0 degrees, east is 90 degrees, south is 180 degrees, west is 270 degrees) does not match the azimuth range available by the polar plot in gnuplot (0 degrees is to the right, 90 degrees is up, 180 degrees is to the left). And the horizon is 0 in $GPGSV messages and maximum range in gnuplot. Time for some perl massaging of the $GPGSV lines to gnuplot orientation:
#!/usr/bin/perl -w

use strict;

while (<>){
    if (/^\$GPGSV,\d+,\d+,\d+,([\d,]+)\*[0-9A-Z]{2}$/){
        my @fields=split(/,/,$1);
        while ($#fields>0){
            my $sv=shift @fields;
            my $elevation=shift @fields;
            my $azimuth=shift @fields;
            my $signal=shift @fields;
            if ($signal){
                warn sprintf "SV %d elevation %d azimuth %d signal %d\n",$sv,$elevation,$azimuth,$signal;
                if ($azimuth<0) {
                printf "%3d %3d\n",$azimuth,90-$elevation;
And indeed we have data:
SV 33 elevation 27 azimuth 205 signal 38
SV 29 elevation 83 azimuth 100 signal 44
SV 31 elevation 48 azimuth 227 signal 45
SV 21 elevation 47 azimuth 169 signal 44
SV 25 elevation 29 azimuth 122 signal 41
And azimuth/elevation in a file that gnuplot can handle:
245  63
  8   9
283  40
226  44
326  64
The azimuth/elevation data, modified for gnuplot. And the next step is a gnuplot plotscript:
set size square
set angles degrees
set polar
set grid polar 30
set xtics 30
unset border
unset param
set xrange[-90:90]
set yrange[-90:90]
set rrange[0:360]
set trange[0:90]

set title "GPS satellite tracks"
set xlabel "Azimuth"
set ylabel "Elevation"
set terminal png size 600,600
set output "gpsazel.png"
plot "gpsazel.dat" using 1:2 notitle
Which indeed gives a nice plot of some recent data.

Main conclusion: this sirf star II gps is 'too good' for this application. For example, one measurement:
SV 5 elevation 4 azimuth 86 signal 37
Satellite 5 seen at an elevation of 4 degrees above the horizon in easterly direction with a signal/noise ratio of 37 dB. There are high buildings (4 floors) in the easterly direction so I think I'm seeing the gps receiver being way too good at this.

The good part is that I'm not the first one to think of this: GPS Skyline: A Panorama in 1.6GHz Microwave-"Light" which suggests I need to find the right cutoff value for my type of GPS unit.

2014-04-14 (#)
This evening had no high Saudisat SO-50 passes at friendly times but it did have a nice overhead ISS pass around 22:15 localtime. I noticed the AFSK signal later than I expected according to the azimuth/elevation calculated by gpredict and reception stayed fine when gpredict said elevation had dropped to about 1 degree above the Eastern horizon. There are high buildings in this direction, so I guess the orbit has changed a bit compared to the latest data I had. AFSK reception was fine, maybe I should try to record the outgoing audio somehow so I can decode it later.

I have programmed the ISS region 2 voice frequency from the ISS Frequencies - ISS Fan Club into my radio so I could hear voice communications or even try to make a contact when the ISS is overhead. Reading the Recorded ISS radio contacts - ISS Fan Club page shows some radio amateurs have been trying that for 2 years before succeeding so it won't happen easily.

2014-04-07 (#)
Trying to hear and work the SO-50 satellite as PD4KH portable has one downside: certain types of weather don't agree. The first pass this evening was really nice, straight overhead. But closer to earth there were serious rainclouds overhead causing a downpour so I opted to skip that one. A pass later in the evening started dry so I went outside. During the pass it started to rain again a bit so I had to dry my laptop after I was done! It was a low West-North pass and those are harder to follow from our house. But I did hear some voices and I think I understood at least one callsign, but checking the live oscar satellite status page shows no callsign matching what I think I heard.

Update 2014-04-08: Another nicely timed West-North pass, without rain this time. I heard some interference, including someone who decided that whistling at the satellite was a good idea. Probably taken directly from the "what NOT to do with amateur satellites" handbook.

The pages maintained by Mike Rupprecht DK3WN about amateur satellites have some realaudio samples of good and bad use of the amateur satellites: SaudiSat 41, 42, 50 - Mike Rupprecht - Amateurfunk Betrieb über FM Satelliten - Mike Rupprecht - Amateurfunk I don't agree with the quoted statement by LA2QAA in the last article of being proud of never using the "easy" FM amateur satellites. A more positive approach is needed in my opinion.

One "mental" switch I have a problem with: with the squelch completely open I hear noise when I'm either not listening to the satellite or the satellite is not in use by another amateur. With listening to "earth" FM repeaters at normal squelch settings I'm used to noise meaning that someone is trying to use the repeater but failing. This means pressing the transmit button when hearing noise on the satellite is a bit "unnatural" to me.

2014-04-02 (#)
I ordered and received an Arrow Antenna: hand held portable dual band 2m/70cm Yagi satellite antenna. It came in last Saturday afternoon. And now I constantly look at the amateur satellite trackers on my laptop and tablet to see when passes come up for satellites that I can receive in FM. First receiving: I don't want to be the proverbial alligator on the amateur satellites (all mouth and no ears).

Our house being in a quite built-up area means when the elevation doesn't get above around 20 degrees there will not be a lot of chance to receive the satellite.

What I am looking for is satellites I can receive (and work) with the FM handheld transceiver. I focus on Saudisat-1c, the International Space Station and Oscar-11. Oscar-11 is an older amateur satellite but I could be lucky with receiving telemetry in AFSK format.

This evening had an 'easy' pass of Saudisat-1c usually known as SO-50, straight over my head. The obvious upside is: no buildings in the way. The less obvious upside: a shorter distance to the satellite, less signall loss. With headphones to hear the incoming audio in both ears I was able to hear callsigns. I'm not sure I heard a complete QSO. What I learned was that the moment the reception is clearest (shortest radio path) is also the moment of the biggest Doppler shift in receive frequency.

I also had a reasonably easy pass Saturday evening. I reported both passes to the OSCAR Satellite Status page by KD5QGR.

Update 2014-04-04: This evening I heard the AFSK1200 noises from an ISS pass! Amazing how fast the enormous mass of the International Space Station flies across the horizon. In 6 minutes it passed from azimuth 218⁰ (southwest) to 80⁰ (north of east).

2014-03-29 (#)
Looking at the DSL spectrum of the new VDSL modem I noticed the used frequencies overlap with spectrum used by AM broadcast stations. With a few stations in the area that transmit at reasonable amounts of power, I thought this might be a source of interference. Someone who lives close to the AM transmitter near IJsselstein has noticed the carrier containing 675 kHz isn't used, the frequency of the nearby AM transmitter. Found at HF-dichte modem/router gezocht - zendamateur.com forum in Dutch

When I searched whether someone had looked into this matter before me I found A VDSL tutorial by Frank Sjöberg which notes:
The main source of RFI is believed to be amateur radio (HAM) transmitters. This is because they can be located just a few meters from a telephone line and the transmitting power can be relatively high - up to 400 W in the UK and 1.5 kW in the USA. Even though AM broadcast transmitters use much higher transmit power, they are usually not located so close to the telephone wires. The number of active AM transmitters is also quite small compared to the number of amateur radio users, especially in Europe. Furthermore, AM-broadcast transmitters always transmit the carrier wave, which makes them more stationary and easier to deal with, compared to amateur radio users that can change frequency often and mostly transmit single side-band (SSB) modulated signals.
From a DSL viewpoint amateur radio is indeed unpredictable and a strong source of interference. Time for fiber.

I don't transmit on HF yet, so I don't have any personal experience yet. Looking at the signal/noise ratio graph from the modem there may indeed be a small dip in signal/noise ratio around 675 kHz.

2014-03-23 (#)
Due to some current events I am interested again in receiving ADS-B signals from aircrafts, I started with ADS-B on the rtl-sdr stick in August 2013. ADS-B antenna 1090 MHz colineair design I still have dump1090 working, and I built a colineair antenna based on the design mentioned on SBS-1 & SBS-3 Mode-S / ADSB Virtual Radar : User Forum xx • View topic - How tu build antenna for sbs-1?. Old electric wire was easy to adopt for this target. The result is clearly visible, I can now see high-altitude aircrafts from beyond Eindhoven and Den Helder.

But I also noticed the most 'interesting' aircrafts are the ones that do not show location information in the dump1090 console display. Some are gliders, such as
Hex    Flight   Altitude  Speed   Lat       Lon       Track  Messages Seen   .
4849c6 PH1280   2025      0       0.000     0.000     0     73        0 sec
But others will send high numbers of messages and when I search on the Hex ModeS code I find them listed as militairy aircraft.
Hex    Flight   Altitude  Speed   Lat       Lon       Track  Messages Seen   .
ae0403 DUKE37   15000     0       0.000     0.000     0     1840      0 sec

Update: It's remarkable that 'lower Dutch airspace' closes at 23:00 localtime. After that time I see nothing below flightlevel 30000 feet (my guess). Looking at Flightradar for Schiphol shows maintenance vehicles and a few late arrivals.

Update 2014-03-24: Ok, one more extra interesting signal:
Hex    Flight   Altitude  Speed   Lat       Lon       Track  Messages Seen  .
4d03cd NATO01   31075     0       0.000     0.000     0     3225      0 sec
One of the Awacs radar airplanes operating from NATO Air Base Geilenkirchen is active, as announced. Lucky you can't hear those very well when they are at 31075 feet. It doesn't announce its location but I think an Awacs radar airplane is perfectly capable of avoiding any plane...

Update 2014-03-25: And the other Awacs plane manages to not get out of range longer than 60 seconds (timeout in dump1090 for tracking a flight), leading to a very high number of messages from one flight:
Hex    Flight   Altitude  Speed   Lat       Lon       Track  Messages Seen   .
4d03c9 NATO02   29000     0       0.000     0.000     0     83597     0 sec

2014-03-19 (#)
Gisterenavond op de clubavond van de Veron afdeling A08 Centrum eens gespeeld met PSK31 op HF (20m band).

PSK31 is een 'digitale mode' waarin tekst (letters en cijfers) in een smalbandig radio signaal uitgewisseld worden. Er is dus altijd een computer met geluidskaart nodig, maar met de huidige stand van zaken kan elke moderne computer dat.

Ik had al eens eerder succes met het decoderen van PSK31 verkeer maar nu heb ik ook zelf PSK31 contacten gemaakt. Ik heb dat gedaan onder de roepletters van het clubstation, PI4UTR omdat dat de standaard instellingen zijn van de PSK31 software. En het is natuurlijk handig dat onder toezicht van een amateur met F-licentie het volle vermogen gebruikt mag worden.

Ik heb daar op de standaard PSK31 frequentie op de 20meter band 14.070 MHz gekeken naar verkeer, gereageerd op oproepen en zelf ook een paar keer CQ geroepen waarop gereageerd werd. Dat leverde contacten op met: RK6LN (Rusland), UX7MX (Oekraïne), IZ8DSY (Italië), IZ8OFO (Italië), IK7NXU (Italië), IZ8GUH (Italië), EA3KU (Spanje), UX5IQ (Oekraïne), PY2MR (Brazilië), CT2KCK (Portugal), UT5AJ (Oekraïne), RW0LBZ (Rusland), CT2JBK (Portugal)

Na een van de reacties op een CQ kwam zelfs een tweede reactie van een andere amateur, voor mij een indicatie dat ik leuk bezig was.

Een mooie score, de afstand tot de Brazilië was ruim 8200 kilometer volgens de gebruikte software, MixW. Dit is software voor digitale amateur radio modes en logging onder Windows die beschikbaar is op de club. Als ik zelf iets met PSK31 wil doen ga ik natuurlijk richting Linux met Fldigi.

Het ging bijna allemaal met de macro functies in MixW. Ik zou zelf ook wel eens uitgebreidere verbindingen willen maken waarin ik wat meer tik maar het was ook duidelijk dat er veel radioamateurs op zoek zijn naar korte verbindingen waarin ze wat basisgegevens uitwisselen en dan doorgaan naar het volgende contact voor in de log.

Een voordeel wat de digitale modes hebben waarmee je met je toetsenbord werkt: dat kan in relatieve stilte. Ik kan me helemaal voorstellen dat ik 's avonds met een slapend kind in de buurt liever wat zit te tikken dan zit te praten in een microfoon.

2014-03-16 (#)
Ik ben weer naar de Landelijke Radio Vlooienmarkt geweest in het Autotron in Rosmalen, gisteren 15 maart. Ik heb gekeken naar een antenne voor satelliet-werk maar niet echt iets goed passends gevonden, dus ik ga toch maar eens kijken wat de verzendkosten zijn voor de Arrow Antenna: hand held portable dual band 2m/70cm Yagi satellite antenna. Volgens diverse reviews de ideale antenne voor werken met amateur satellieten. En een goeie richtantenne voor 2m/70cm, die in de 'Backpack' uitvoering ook nog prima mee te nemen is.

Veron cursusboek voor het F-examen, omslag Wat ik wel aangeschaft heb is het Veron cursusboek voor het F-examen. Het goede voornemen is duidelijk om dat cursusboek door te gaan werken en dan met behulp van proefexamens te gaan bekijken of ik nog op een echte cursus wil om het te vervolmaken of dat ik voor een examen voor de F-licentie ga. Geen haast, maar wel iets om aan te werken.

Update: De arrow antenne is besteld en geleverd.

2014-03-16 (#)
Article about the enforcement by the FCC (US department which manages radio frequency spectrum) of radio interference cases: FCC Agents Trace Radio Interference to Doorbells, Videogames, Blankets - Wall Street Journal.

Even a source of interference which has potential to cause more problems than just a fine for radio interference shows up in the article:
Radio hobbyist Tom Thompson of Boulder, Colo., last year tracked a signal using a homemade contraption. After knocking on the suspect's door, he traced it to ballasts on marijuana grow-room lights. He says he built a filter that the grower agreed to use.
Found via HamRadioDaily

2014-03-14 (#)
Yesterday evening was spent repairing some other stuff and soldering a cable from 2.5mm jack to 3.5mm jack so I can use normal headphones on my Wouxun KG-UVD1P. Using full headphones with audio in both ears helps me listen to amateur satellites. The usual approach to amateur satellite listening is to disable the squelch so one can hear the first bits of signal coming out of the noise. But this noise is somewhat annoying to any people nearby. So, headphones to the rescue. This evening I tested this setup. I looked at upcoming passes with gpredict and found out satellites HO-68 and FO-29 were going to make a pass shortly after another. So I was outside (in the cold..) waving with the antenna of the radio, but heard nothing. I knew the HO-68 FM transponder was probably not working and the FO-29 only has SSB so the radio wasn't going to make much of it. I checked with gpredict what passes of 'easier' amateur satellites like SO-50 are going to happen later this week.

Having the 'radio window' in gpredict open with the doppler shift correction makes tuning a lot easier.

2014-03-03 (#)
Vandaag is het precies 34 jaar geleden dat 27 MHz communicatie in Nederland werd geintroduceerd, 27 MC artikel op de nederlandse wikipedia. Ik luister wel eens met een scanner naar 27 MHz verkeer, erg vermakelijk.

2014-02-21 (#)
I almost started to digres in my last post getting an APRS report out using an android device, aprsdroid and a wouxun radio about the privacy implications but decided to separate that issue. It works, and I am not going to invest in it.

APRS is nice, but for me it has privacy implications: it reports my position in real-time which is more than I want to share with the world, even as an amateur radio experiment. I know there are people who will post their bicycling tours or runs on-line as they happen but I don't like publishing my wereabouts, especially not in (near) real-time. Enough people can browse the mobile telecom location registers as it is.

So I think I'll leave the APRS location experiments at this and I'll go look at other amateur radio stuff. There is enough to play with!

I know APRS is bigger than just reporting location. Getting my weatherstation in Utrecht Overvecht to report weather to the APRS citizen weather observer program is on my wishlist.

2014-02-20 (#)
Again playing a bit with APRS and aprsdroid. No luck with using a 3.5mm to 3.5mm audio cable, the vox on the wouxun KG-UVD1P does not trigger at all. I did test with the audio from aprsdroid near the microphone of my laptop and decoding it with multimon, and that works:
AFSK1200: fm PD4KH-7 to APDR12-0 via WIDE1-1 UI^ pid=F0
=5206.  N/00507.  E$/A=000162 http://pd4kh.idefix.net/
pd4kh on aprs.fi display The 'audio through the air' method works with the radio right next to the internal speaker of the android device: with some fiddling of audio settings on the android device and vox settings on the wouxun I can send out a position report and it shows up on the aprs network! Wouxon vox level at 5, audio output type "music", audio level medium.

The pink square is because I don't give out a very precise location on purpose.

2014-02-12 (#)
I decided to try aprsdroid on my android device. First and easiest should be to select the option AFSK via Speaker/Mic and I hoped it would work when the speaker and microphone of the portable radio are near the microphone and speaker of the android device. No luck: no transmitted APRS packet was found via aprs.fi call PD4KH and no incoming packet was decoded. I guess there was too much distortion and interference. I looked at the aprsdroid settings a lot since I noticed outgoing audio seems to be fixed at the highest volume, which can also be an issue.

In the video Get Started with APRS for only $30! - youtube.com video a simple cable from the android device to the radio is used, so it can be done.

Going for a solution like an Mobilinkd is more expensive, but maybe interesting in the long run when I want to do more with APRS. For now, an interim solution would be nice: building the right cable to get audio from the radio to the android device and back. I found the specs for such a cable at iPhone / Baofeng interface bouw en schema - PA4TW which can be adjusted for the android device and Wouxun. And PA4TW has used it for APRS in Aprs via porto en iPhone - PA4TW.

Old analog telephone equipment can be a source of 600 ohm 1:1 transformers, so I guess some old equipment will have to donate those when I go for such a cable.

2014-02-05 (#)
De eerste QSL-kaart is binnen! Van het contact met PD6SHELL een leuk kaartje.

2014-02-02 (#)
The change to the new weatherstation computer also means the powerline network is now gone. And I mean gone, not just disconnected "just in case". The adapters are back in a crate. And this should mean the HF spectrum should look nicer than in my earlier measurements. Future measurements may confirm this.

The weatherstation computer now uses Wi-Fi to talk to the rest of the network. Since the access-point is on the same ground level the signal quality is good and speed is high enough.

2014-01-29 (#)
Een mooi verhaal over een enthousiaste jonge beginnende radio amateur die met wat hulp mooie dingen aan het doen is: PI4RCG sponsort Lithouwse novice zendamateur LY5AT, door PA3FYM.

2014-01-13 (#)
I had a look what software is available for predicting satellite passes in the ubuntu ham radio software repositories.
predict-g1yyh in an xterm screenshot
predict-g1yyh in an xterm
I found PREDICT satellite tracking and orbital prediction program which does all the calculations given recent Keplerian elements which are available from sources like Keplerian elements at Amsat and Current NORAD Two-Line Element Sets at celestrak. Predict comes in two versions: predict in a version from May 2006 and predict-g1yyh. They look a bit different but the calculations are the same in the end.

Important part (to me) is the software also does the calculations for doppler shift. Doppler shift does occur measurably in radio signals when the two stations have a high enough speed difference between them. Since amateur radio satellites are low earth orbit satellites, the speed is measured in kilometers per second and the shift is there and should be taken into account. Shifts in the 70cm band are high enough that you need to retune the radio. As visible in the screenshot predict does calculate the frequencies when the satellite is visible.

gsat screenshot
gsat graphical client for predict screenshot
The interesting part is that predict and predict-g1yyh can also run as a server program where clients can access the data. One of the interesting clients is gsat from package predict-gsat. With gsat a world map is plotted with the home location and the satellite footprint visible and the data for antenna direction and doppler shift is shown.

gpredict screenshot main window
gpredict screenshot main window
I also found package gpredict which is totally not related to predict. In my opinion gpredict has a more modern interface (it's gtk+ based) but it lacks support for doppler shift. This makes it somewhat less interesting for radio use.

gpredict screenshot radio control with doppler shift
gpredict screenshot radio control with doppler shift.
Update: gpredict can support doppler shift when it thinks it can control a radio. Configuring a radio with RX only support will make the 'Radio Control' window available where you can select the satellite and its services when it is known to gpredict under 'Target' or enter the uplink and downlink frequencies of the satellite by hand, select 'track' and see the result of the doppler shift calculations.

2014-01-11 (#)
I wanted to experiment a bit with rtl_tcp on ritchie which has linux kernel 3.12, and after inserting the stick I noticed the following in the syslog:
[405465.908104] usb 1-3: new high-speed USB device number 2 using ehci-pci
[405466.052247] usb 1-3: New USB device found, idVendor=0bda, idProduct=2838
[405466.052274] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[405466.052293] usb 1-3: Product: RTL2838UHIDIR
[405466.052310] usb 1-3: Manufacturer: Realtek
[405466.052328] usb 1-3: SerialNumber: 00000001
[405466.217234] usb 1-3: dvb_usb_v2: found a 'Realtek RTL2832U reference design' in warm state
[405466.285098] usb 1-3: dvb_usb_v2: will pass the complete MPEG2 transport stream to the software demuxer
[405466.285208] DVB: registering new adapter (Realtek RTL2832U reference design)
[405466.348588] usb 1-3: DVB: registering adapter 0 frontend 0 (Realtek RTL2832 (DVB-T))...
[405466.378308] r820t 0-001a: creating new instance
[405466.390283] r820t 0-001a: Rafael Micro r820t successfully identified
[405466.397306] Registered IR keymap rc-empty
[405466.397785] input: Realtek RTL2832U reference design as /devices/pci0000:00/0000:00:0f.5/usb1/1-3/rc/rc0/input5
[405466.404262] rc0: Realtek RTL2832U reference design as /devices/pci0000:00/0000:00:0f.5/usb1/1-3/rc/rc0
[405466.449642] IR NEC protocol handler initialized
[405466.453552] IR RC5(x) protocol handler initialized
[405466.459768] IR RC6 protocol handler initialized
[405466.470835] usb 1-3: dvb_usb_v2: schedule remote query interval to 400 msecs
[405466.471385] IR JVC protocol handler initialized
[405466.474504] IR Sony protocol handler initialized
[405466.481423] IR SANYO protocol handler initialized
[405466.483311] usb 1-3: dvb_usb_v2: 'Realtek RTL2832U reference design' successfully initialized and connected
[405466.483477] usbcore: registered new interface driver dvb_usb_rtl28xxu
[405466.493045] input: MCE IR Keyboard/Mouse (dvb_usb_rtl28xxu) as /devices/virtual/input/input6
[405466.498074] IR MCE Keyboard/mouse protocol handler initialized
[405466.501562] lirc_dev: IR Remote Control driver registered, major 251 
[405466.510997] rc rc0: lirc_dev: driver ir-lirc-codec (dvb_usb_rtl28xxu) registered at minor = 0
[405466.511017] IR LIRC bridge handler initialized
It has valid drivers as dvb-t receiver and ir receiver now! That's not what I wanted, I want raw usb access for rtl_tcp. Time to blacklist certain modules:
blacklist dvb_usb_rtl28xxu
blacklist rtl2830
blacklist rtl2832
blacklist lirc_dev
And now no drivers get loaded and rtl_tcp has raw usb access again after updating the udev rules.

No success with gqrx using a remote rtl_tcp: audio was stuttering and frequency changes were visible in rtl_tcp but didn't really happen, there was a huge lag. Traffic between the system running rtl_tcp and gqrx was going over a wireless network, a linux router and a wired network. Bandwidth was not a problem.

I was considering running one rtl-sdr stick with the HF convertor in the shed so it would have less interference but that doesn't seem feasible at the moment.

2014-01-09 (#)
Vandaag moest ik wat dingen met de auto doen. Daarmee kon ook de porto mee met de raamantenne aan de buitenkan van de auto. Dat werkte prima, PI3UTR was prima te volgen en een QSO maken lukte ook zonder problemen. Met dezelfde porto en hetzelfde vermogen waarmee ik op de ligfiets er maar moeilijk overheen kom lukte het met een net iets hogere antenne die zeker rechtop zit prima.

2014-01-01 (#)
Ik was vandaag op de heuvel Hettenheuvel in het Bergherbosch bij Braamt. Ik had de porto mee en op een kant van de heuvel met zicht naar het westen probeerde ik PI3UTR te ontvangen wat lukte. Niet storingsvrij maar duidelijk genoeg om de callgever te verstaan (Q3). De repeater openen lukte niet met de 5W porto. Volgens het hoogtebestand Nederland is de hoogte daar 70 tot 90 meter.

Ik heb daarna eens aan deze link gerekend in Radio Mobile online Radio study pi3utr naar bergherbos en gezien dat van PI3UTR naar deze locatie line-of-sight precies door de bomen van de heuvelrug gaat. Radio study pi3utr naar bergherbos, stukje heuvelrug De afstand was dus iets meer dan 81 kilometer.

Dit geeft wel aan waarom deze repeaterfrequentie gecoördineerd moet worden met Duitsland: het Bergherbosch is nog net niet in Duitsland, maar het scheelt weinig. Op een hoge locatie aan de andere kant van de grens of bij condities zal deze zeker te ontvangen zijn.

2013-12-28 (#)
Today I listened to an amateur radio on the International Space Station (ARISS) contact: Saturday 28 December, ARISS contact planned with Scout group in The Netherlands. This time I listened in the backyard at home, which is a lot more enclosed by other buildings than the location I used on the previous pass, the roof of a 4-floor building at work.

Reasonable reception started in the answer to the 7th question and dropped away in the answer to the 14th question.

Good to hear scouting and ham-radio being used in such a way!

2013-12-27 (#)
When I get around to wardriving lately I use the wigle app for android, so I decided to repurpose the wardrive box as shednet computer. This will also mean I can stop using PLC network to link the shed computer to the rest of the network, replacing it with wifi. Using PLC offends the radio amateur in me and people at the radio club now ask me whether I dumped it already. So, time for different hardware which as a plus will also use less power.

I already built in a laptop harddisk in the wardrive box and removed the compact flash holding the wardriving box image (I'll save it so I can restart using the wardriving box if needed). The alix 1c can work nicely with an IDE laptop harddisk.
2.5 inch laptop harddisk in ritchie
The laptop harddisk built into the ritchie mini-itx case

The installation will probably be done with a recent debian jessie distribution.

Plans for the new shednet computer include an ntp server, but since the current gps unit (gpskit) seems to fail after running for a few days in the test setup that may have to wait.

Items before 2013-12-27
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