I passed my novice radio amateur exam in March 2013 and I registered the
PD4KH (pappa delta four kilo hotel!).
I passed my full radio amateur exam in March 2016 and I registered the callsign
PE4KH (pappa echo four kilo hotel!).
PE4KH on qrz.com
PE4KH on hamqth.com
I am usually located around maidenhead locator: JO22NC
After the problems with the laptop controlling the radio when I participated in the SCC RTTY contest 2017 I decided to build a common mode choke. This is a filter that should keep the radio frequency signals at the side of the antenna. Based on the simple design with a piece of PVC pipe with 8 windings of Aircell-7 coax I still had lying around. The PVC pipe was donated by a fellow radio amateur who had it in his junkbox. I drew a pencil line on the pipe, decided where to drill holes for the coax cable (using a 16 millimeter drill) and where to drill holes for tiewraps to hold the coax. After drilling the holes it was a matter of winding the coax correctly, mounting the cable with tiewraps and soldering the connectors to the cable. In the first testing the filter worked fine, completely stopping the interference to the keyboard of my "shack computer" and even reducing incoming noise on the 10 meter band.
I realized today I never wrote an article about finishing the linked dipole kit I bought a year ago and started making my own dipole from Linked dipole portable HF antenna kit. I used the SARK100 antenna analyzer to test it on each band: first 15 meter, after that 20 meter and I finished with 40 meter. I did 15 and 20 meter on two separate meetings at my radio club and 40 meter in a park near our home. As mentioned by others you need to take the time to tune this antenna to the right length. Each band took me about 2 hours which turned out to be what I could do in one evening at the radio club. The proof is always the first contact and that happened when I brought it on our holiday to Germany and Austria. The tree behind our tent at the campsite in Austria was not high enough to support the 40 meter length of the antenna but I just set it up for 20 meters and that worked fine. It's remarkable how forgiving this antenna is after tuning. I just set up something resembling an inverted V and my radio found it near perfect, very little reading on the SWR meter. First completed contact was with a radio amateur at the same campsite so that wasn't very hard. I did hear a Dutch radio amateur using a serious amplifier to try to reach me but lacking output power he did not hear my answer. Anyway, project officially finished.
I was reading about a solar flare maybe coming in the direction of earth on several places related to amateur radio. Propagation via the ionosphere is affected by solar flares: a solar flare will change the ionization of the ionosphere seriously. By chance I had wsjt-x running decoding FT8 signals this morning but I was busy with other stuff. When I returned to the radio shack the last decode was at 11:55:30 UTC and not a single decode after that, and just the local noise on the radio.
Again this year had the SCC RTTY contest in the same weekend as the barbeque of the radio club so the solution was to work in the contest from the location of the radio club. I set up with the endfed antenna in the available field. That field is close to some houses so I had some interference. And the main problem was that the computer control between the laptop running fldigi (the contest logging software) and the radio regularly gave problems, usually leaving the radio in transmit mode. The laptop and the computer interface aren't shielded very well which is probably a reason, combined with the use of the endfed antenna which is known for causing interference since it's an asymmetric antenna. In the end I made 53 contacts. Less than the number of contacts in previous SCC RTTY contest but I had limited time and local noise was higher than I expected. For a next time I am working on a common mode choke to limit interference to the computer and maybe some noise. And probably next time I contest at the radio club I will try to use a different antenna location.
This morning I had some time and a good reason to leave the house. So I packed the radio, batteries and headphones and loaded all of it in the trailer of the recumbent and cycled to the bend in the road with a table and some trees where I operated portable before. The local noise was very low again, about S1 on the 20 meter amateur band and about S4 on the 40 meter band. But conditions made the 20 meter band very quiet so I tried answering some calls on the 40 meter band first. In total I had 5 contacts, three of which were activations in the world wide flora and fauna program. Some of the contacts later in the morning were on the 20 meter band after it opened up. All in all a nice way to spend the morning. Things noticed:
- My newest lead-acid battery is failing already. It has trouble charging and when the charger thinks it is full it will drop output voltage way too fast. Time for a new battery with more capacity. 20 to 25 amp-hours would be a good value.
- Getting a rope up in a tree is still annoying, I had to try way too many times. I am looking at fiber poles for portable operations. That would also mean there are possible locations for operating outdoor portable a lot closer to our home. Just a parkbench and some way to tie the fiber mast to something vertical is enough.
Other people from my radioclub were reporting they uploaded FT8 contacts to LoTW so I wanted to try this too. I uploaded earlier contacts as 'DATA' (and got some confirmations) but FT8 is the correct mode so I wanted to re-upload them. After my earlier experiences uploading FT8 contacts to eQSL I expected some database work to be able to upload those contacts again. Finding the right field to set to the right value was a bit of work since I expected the approach to be similar but it wasn't. In the end:$ mysql -S /home/koos/.config/cqrlog/database/sock cqrlog002 mysql> update cqrlog_main set lotw_qsls = '' where mode='FT8'; Query OK, 77 rows affected (0.01 sec) Rows matched: 78 Changed: 77 Warnings: 0That's after trying most lotw related fields and values.
Almost two 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. Image credits:
- License plate generated with Kenteken generator
- Dom tower Utrecht from Utrecht Center Central Houses Dom Dom Tower
- Shelf with radio, power supply: own picture, also available at Alan K205 power supply, tuner and radio | KvdHout on flickr
- Recumbent bicycle with radio on wooden table: own picture
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.
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.
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.