2017-08-22 New QSL cards ordered, again from LZ3HI 1 day ago
Almost years after I ordered QSL cards for PD4KH they ran out. I had to print stickers with the PE4KH call sign for a while to update the cards. Now I had time to make new cards and see what the options where. I promised myself nicer cards with not just the standard data but nice colour pictures on the front side so I looked at ideas, drew some things on paper and worked a few evenings in the Gimp to get the ideas into something that would survive being printed. I created files for printing at 600 dots per inch so there should be no strange printing artefacts.
2017-07-24 Last night receiving ISS SSTV images 4 weeks ago
And a third night. I used the timed recording option of audacity, which in the current linux version does not offer the option to set in advance how to save the project. This time I 'only' recorded for 7 hours, and was able to save the project afterwards without needing a recover. But on reloading the saved project audacity complained about some internal error in it, and it still had the problem of assuming 44.1 kHz sampling while showing the project sample rate as 48 kHz. Anyway, images decoded from the audio and I even recieved a few new ones.
2017-07-23 Another night of receiving ISS SSTV images 1 month ago
On the night from Friday to Saturday I had the whole setup ready to receive more ISS SSTV images. And nothing was received since I had the antenna unplugged during Friday because of thunderstorms and forgot to plug it back in. So when I found that out I put a note on my desk with 'Antenna unplugged?' which can be a reminder to unplug it when I'm done or plug it in when I want to receive something. On the night from Saturday to Sunday I plugged the antenna in and let the whole setup run again like on the earlier run on Friday Received slow scan TV images from ISS while I was sleeping. To make sure I had the antenna plugged in I tuned to 145.750 MHz where I can hear a distant repeater faintly. Again audacity hung after the recording, and this time on recovery it had some issues with the saved project. At first I could see and hear audio of SSTV passes but qsstv could not decode anything. In the waterfall display of qsstv it looked like the frequencies were too low. I had a thought that maybe something decided the samplerate was back to 44.1 kHz so I simply speeded the audio of an image pass up by 8.8435% and suddenly it decoded fine. In the end I decoded 11 images from the ISS SSTV project. Numbers seen 8, 10, 9, 6, 7, 8, 6, 4, 5, 6. And 2 images from nearby radio amateurs who weren't operating according to the bandplan... but at least did not interfere with the ISS SSTV transmissions.
2017-07-21 Received slow scan TV images from ISS while I was sleeping 1 month ago
I read about the current ARISS Celebrates it’s 20th Anniversary through SSTV Event and noticed the planned times weren't really compatible with my day/night cyclus. I know, as a hardcore radio amateur I should be up at the weirdest hours for rare events but I also like my sleep a lot and my wife really dislikes alarms at weird hours. Automation to the rescue: I decided to record all of a night of ISS signals on the computer with audacity and decode images from it later. The computer adjusted the radio for doppler using gpredict. Since I don't have an automatic rotor for satellite antennas I used the VHF/UHF vertical. This may seem strange but the weakest signals from ISS are when it is right above the horizon (which is when the vertical has the best reception). And as noticed on earlier SSTV events that compared to other amateur satellites the ISS has a strong signal. So I left it running for a night and checked the results afterwards. The result was a 9 hour recording and audacity decided to hang after stopping the recording. I made a backup copy of the audio data just to be safe and restarted audacity. Luckily it recovered the project fine after restarting. With a recent version of qsstv I decoded the recorded audio and searched for ISS passes in the recording. The result is 13 decodes in one night. It turns out it received audio from a number of low passes that I did not see in gpredict because I have gpredict set up to skip low passes (those that don't come above a 20 degree angle above the horizon). But the strong signals from ISS make those show up in my radio anyway. Decoded and seen the numbers sofar: 11 (partially), 12, 9, 10, 9, 10, 9 (partially), 9, 7, 8.
2017-07-16 Uploading FT8 contacts to eQSL 1 month ago
This evening I noticed incoming FT8 QSO's in eQSL, so the mode is now recognized there. But I needed to retry uploading all FT8 contacts to get them to upload. It took a bit of experimenting, but finally the right SQL command to mark the contacts as not uploaded was:$ mysql -S /home/koos/.config/cqrlog/database/sock cqrlog002 mysql> update cqrlog_main set eqsl_qslsdate = NULL where mode='FT8'; Query OK, 24 rows affected (0.02 sec) Rows matched: 26 Changed: 24 Warnings: 0And now they are all uploaded. That is about a week between first seeing mentions of FT8 in radio amateur news and the first confirmed contacts.
2017-07-16 I participated in the DMC RTTY 2017 contest 1 month ago
Or maybe I should use the word 'played' again: 6 contacts. It was a weekend with not much time for radio and when that time did happen propagation wasn't cooperating very well. The advantage of contests is that there are a lot of stations who want to hear every other station, so I used the last 20 minutes of this contest just to answer a few calls and get in the log.
2017-07-12 New digital mode for amateur radio FT8 1 month ago
This week there was a sudden 'buzz' about a new digital mode for amateur radio from Joe Taylor, K1JT. It's like JT65, with a very minimal exchange (callsign, locator, signal report) but with a lot faster timing: each turn is 15 seconds and from what I can see somewhat more than 13 seconds transmitting. I made the first few contacts today after downloading wsjtx from WSJTX-Development : Greg Beam as Ubuntu package. They are now in my log, but uploading to eQSL / Logbook of The World is not possible yet as 'FT8' is not seen as a valid mode yet. The solution for LoTW seems to be to change to 'DATA' but this solution does not work for eQSL. I'll have to upload those contacts later when the mode is recognized. First contact was with IZ8GNR and I also had contacts with club members PA2RG and PD3RFR. With JT65/JT9 I sometimes get distracted waiting 50 seconds before it's my turn to react again, with FT8 it's more high-speed work (somewhat less than 2 seconds to react to a CQ or an answer). WSJT-X now has an auto-sequence feature which will step through the exchange automatically.
2017-07-09 I participated in the IARU HF Championship 2017 1 month ago
My activity in radio contesting has been in digital mode contests, with one exception in a mixed-mode contest where I also made some voice contacts: the ARI International DX Contest in 2016. But this weekend I seriously entered the IARU HF Championship in 'phone' (speech) mode. I made 59 contacts, 50 on the 20 meter band and 9 on the 40 meter band. I managed to work a lot of the HQ stations I heard active for the various national radio clubs. I heard no serious DX, but the local noise at home is prohibitive for voice contacts anyway. My personal reason for entering this contest was reading about its role in the world radio team championship in the book Contact Sport: A Story of Champions, Airwaves, and a One-Day Race around the World by J.K. George. I used yfktest for the contest logging and found the biggest fixed font I can use which makes the 25*80 xterm almost fill the entire screen. See the screenshot. Claimed results according to yfktest:Band QSO Qpts Dupes Mult1 Mult2 ------------------------------------------- 20 50 112 0 23 0 40 9 13 0 8 0 ------------------------------------------- ALL 58 124 1 31 0 =========================================== Total Score: 3,875
2017-07-03 Reboots of the FT-857 radio 1 month ago
The last week I had a problem with the FT-857 radio rebooting when I started transmitting in digital radio modes (PSK31 or JT65). The reboot showed as the radio giving the standard beep and the display and backlight switching off and on. Searching for clues suggested that some form of radio frequency interference would probably be the source. So I wondered what I changed recently around the radio and remembered I changed something in the power distribution to have connectors available for powering my SARK100 antenna analyzer with a 12 volt battery. Reseating all those power connectors and fixing some wires seems to have stopped the problem.
2017-06-18 I participated in the Ukranian DX Classic RTTY Contest 2017 2 months ago
I participated in the Ukranian DX Classic RTTY Contest 2017 this weekend. I prepared the antenna and the contestmacros Friday evening, but I knew most of Saturday afternoon and Sunday morning would be unavailable. Local noise was bad, it seems interference from solar panels is on the rise and it was a quite sunny day. On the other hand, there was a 10 meter band opening Sunday afternoon, giving me some new multipliers with 8 contacts on that band. But no serious DX in the whole contest, I just saw Eastern Europe and Asiatic Russia active, unlike when I participated in the Ukranian DX Classic RTTY contest 2016. The end result is that I made 70 contacts in somewhat less than 6 hours of operating time. So I participated in the SINGLE-OP ALL 6-HOUR RTTY category.
2017-06-18 Sunny interference 2 months ago
A good sunny day and the effect it has on the HF spectrum: extra interference from solar panels. I'm not sure whether to complain about all solar panels not regularly identifying with their callsign or complain about interference or just give up and find another location for amateur radio.
2017-06-14 Controlling the SARK100 antenna analyzer from Linux 2 months ago
The SARK100 antenna analyzer I bought also has the option to be controlled over an USB interface (other versions even have bluetooth support). Over USB it is possible to automate the measurements and have the results returned to the controlling computer. For Linux software is available: SARK100 Antenna Analyzer Linux Software also via github with updates coddingtonbear/sark-100-antenna-analyzer. I cloned the git repository and guessed that the command to build a 32-bit version would be:koos@thompson:~/radiowork/sark-100-antenna-analyzer$ mkdir build koos@thompson:~/radiowork/sark-100-antenna-analyzer$ cd build koos@thompson:~/radiowork/sark-100-antenna-analyzer/build$ qmake -spec linux-g++ -o Makefile ../analyzer/analyzer.proThis indeed compiled into a working 32-bit binary. Needed because the 'main radio desktop' can't run a 64-bit linux. The laptop does not have this problem.
2017-06-06 Testing a different antenna setup and having fun on the 10 meter band 2 months ago
Almost three years ago I started making PSK31 contacts on the 10 meter band which was my first experience with HF and propagation through the ionosphere as a novice amateur with callsign PD4KH. The 10 meter band is the amateur band from 28.0 MHz to 29.7 MHz. But the propagation through the ionosphere depends on the solar cycle. Currently the cycle is going towards a solar minimum meaning the number of sunspots is very low. Due to the low number of sunspots the propagation of radio signals through the ionosphere back to earth is also very low. After I upgraded to a full license opportunities to use the 10 meter bands were very rare. Up until yesterday I had 5 contacts in the log for PE4KH on the 10 meter band. And yesterday that changed. I was testing with a borrowed fiberglass pole since I want to use that to help me tune the linked dipole kit I bought. I set up the fiberglass pole in the back of our garden using the fence for support and raised it to the full 10 meters with the endfed spiralled around it. At the end I had some wire left to the transformer so I just hung the transformer in the back garden. It took a lot of cable to get from my radio to the antenna far away, but I really wanted to do that experiment, especially to get an idea of the influence on the local interference. On the 20 meter band the interference was about the same, on 40 meters it was a bit less but on 10 meters it was almost gone. And at the same time there was interesting propagation on the 10 meter band. I made several contacts with stations in Poland, Austria, Italy, Northern Ireland and Scotland. Most of those contacts would not have been possible with the noise levels I am used to. An interesting experiment in radio. My first thought was that this antenna setup might be interesting for contesting, but I realised that I really need to keep an eye on the power levels since there is a small footpath right behind our garden for our neighbours. I can't ask them not to use that footpath for an entire contest weekend.
2017-05-22 I bought a SARK100 antenna analyzer 3 months ago
In september 2016 I ordered a balun and a linked dipole kit from sotabeams with the idea to make a lightweight dipole antenna for outdoor use. But there is one very important ingredient to making a dipole: you need an antenna analyzer to get the dimensions right to have optimal reception and transmission into a resonant antenna. I could borrow the antenna analyzer from the club just like I did for measuring my 2m/70cm portable coax antenna but after reading about the (cheap) SARK100 antenna analyzer I decided to buy one myself. One good review I found is It finally arrived! My SARK100 from China. This analyzer seems to be a serious case of an 'open source' design being picked up by the Chinese electronics manufacturers and sold in high numbers. I bought one for a reasonable price at an aliexpress seller that had good reviews and orders before. It arrived today and the first tests look really good. First I measured my dummy load (to get an idea of how it was doing as an analyzer) and after that the 10m/20m/40m endfed antenna that was hanging outside anyway for the EU PSK DX Contest 2017 that I participated in. This antenna isn't perfect (as visible in the picture) but it does the job. So now I have to find the time to design a linked dipole as I want it, build it and measure / adjust it until it does what I want. It's a good thing I can easily calculate linked dipoles at Various tools for SOTA purposes. My plan is to build a 15-20-40 meter band dipole. The selection of bands is because outdoors I will use less digital modes and 40 meters is the longest size for a dipole that is usable to set up. The angle of the dipole and therefore the height of the centerpoint also has an influence on the antenna. But I don't know how high the tree will be, so I will have to make a guess.
My sark100 antenna analyzer
2017-05-21 I participated in the EU PSK DX Contest 2017 3 months ago
I noted the EU PSK DX Contest in the contestcalendar and decided to participate. Conditions did not cooperate very well and I found some issues with my setup during the contest. But in the end I made 57 contacts. Not very good given my scores earlier this year but I think the big issues with local HF noise started after the previous contest.Total number of QSO in your log is 57, Including 0 QSO with errors, Valid QSO - 57 Band QSOs Dupes Points Mults 160 0 0 0 0 80 0 0 0 0 40 0 0 0 0 20 57 0 117 64 15 0 0 0 0 10 0 0 0 0 ====================================== Total 57 0 117 64 Claimed score is 7488 points
2017-05-14 Upgrading the home network to shielded/foiled cable (s/ftp) 3 months ago
I was looking at on-line offers of shielded/foiled network cable and found out it's not that expensive anymore. And with the 'keystone' connectors it looks like it's not that complicated to make neat and very well shielded connections. But it's always a good plan to check the local electronics hobby shop. We still have one in the center of Utrecht: radio centrum where they had 1 meter and 2 meter patchcables for a very nice price (competitive with on-line shops) right up for grabs. So the first set of short cables that are always in use for gigabit are now s/ftp category 6 cables. I hope this improves radio reception. I still think I will order longer cable and keystone connectors and holders for the longer cables.
2017-05-10 Digging for the source(s) of HF interference with a complete powerdown 3 months ago
Today I had planned to dig deep into the sources of the HF interference by switching off the electricity in the whole house and seeing what difference that would make and if it did, search for sources. I used the 10-20-40 meter band endfed outside, and the 10-20 meter dipole inside. The conclusions are mixed:
So for the 10 meter band and less for the 20 meter band it was good to search in the house for sources of the noise. Found:
- The 40 meter band (that I can only use on the endfed) is not influenced at all by switching off the power.
- The 20 meter band on the dipole gets somewhat less noise when the power is down.
- The 20 meter band on the endfed gets the same amount of noise when the power is down.
- The 10 meter band on the dipole gets no noise at all when the power is down. Change from S8 noise to S0 noise.
- The 10 meter band on the endfed gets 2-3 points less noise when the power is down.
So the problem sources that I can't switch off easily are all part of the home network. My current theory is that 10 meter seems to be affected by gigabit network. My experience is that transmitting on 10 meter indoors causes a network outage. The home network is all Cat-5E at the moment, unshielded twisted pair. It seems an upgrade to s/ftp is in order (with foil and braided wire, the same I do for antenna cable). The thing is that with the current solar cycle 10 meter use is very rare. I haven't made a contact yet in that band in 2017.
- The lights in the attic
- The UPS for the server
- The netgear switch downstairs when ports become active. The switch upstairs probably too, but it's behind the UPS, so interference from the UPS showed up first
- The wireless accesspoint downstairs
2017-05-08 Going full duplex with amateur satellites, part 11 : Tried an XW-2A pass, heard vague signals, no contacts 3 months ago
This evening the only amateur satellite pass at a reasonable time was by the XW-2A satellite, part of CAMSAT XW-2 Satellites - amsat UK and I only heard weak signals which sounded like other radio amateurs tuning their transmitters/receivers but I never heard something like a voice. Or my own signal when I tried transmitting.
2017-05-07 Going full duplex with amateur satellites, part 10 : Still no contacts, investigating AO-85 (Fox-1a) 3 months ago
Passes of amateur satellites aren't always at times that are compatible with other things happening. But the discussion about AO-85 on the amsat-bb mailing list also had some details about the satellite and I also found AO-85 Twist Trick and Other Hints - Spacecomms which explains:Apparently the epoxy caused a change in impedance which essentially “detuned” the antenna. It makes the bird appear deaf. A workaround is to twist the Arrow antenna 90 degrees when you transmit. That is, rotate the antenna until the receive signal is “peaked” and then rotate it 90 degrees when you transmit and back again to receive. The downside to this is if you’re working full duplex when you rotate the antenna 90 degrees to transmit you will often lose the downlink signal and not be able to hear yourself. In my experience I only have to do the twist trick in the beginning and end of the pass when the bird is farthest away. Another fix is to just use more power, but if you only have an HT that’s usually not an option.This, combined with the frequencies up and down being slightly different from the planned frequencies explains the weak signals I hear upon receiving and the difficulty I had getting into the satellite. This evening had a pass of AO-85 which did not leave me time to drag out the whole setup, but I was able to bring the arrow antenna and a handheld radio to check reception to see if the frequency was correct, including doppler correction. It was correct, but reception is indeed quite sensitive to the orientation of the arrow antenna.
2017-05-01 Going full duplex with amateur satellites, part 9 : Filtering the reception, in theory 3 months agoOlder news items for tag hamradio ⇒
I decided to share my woes of the receive side going deaf (receiving nothing) when I transmit with the amsat-bb mailing list, together with a description of the whole setup. The suggestion came from Eduardo PY2RN to not use a preamp and have filtering so the transmitted signal cannot get into the receiving side. I pondered this for a while and realised I already have a filter: the diplexer on the arrow antenna. So to receive on 2 meter and transmit on 70cm I connect the transmitting radio to the 70cm antenna and connect the receiving radio (the rtl-sdr) to the 2 meter antenna via the diplexer, and put a 50 ohms terminating resistor on the 70cm connector of the diplexer to make sure it still shows the right impedance. In a simple test this works, transmitting now has a lot less influence on the rtl-sdr (it's not completely gone yet). I haven't had a good satellite pass yet to try this out.