2023-08-13 Going down the rabbit hole of DJ mixing
I had a heavy case of 'Oh Shiny!' this weekend. Recently I've been viewing and listening some DJ mixes on YouTube, most of them with music from the 1980s which I appreciate a lot. Seeing those DJs mix live in those videos made me wonder 'how do they do it'. In one or more of these mixes I really noticed that a transition seemed to have happened between one well-known song and another, but I wasn't aware of how and when the transition happened. The DJ was so good in mixing the two records together I couldn't hear the point where it happened. In seeking the video I saw that other people viewing the video had been wondering the same, there was clearly a peak in viewing time on the transitions. It was also clear from the look on the face of the DJ he was happy with what he accomplished with that transition! In the 1980s the DJ had an audio mixer and two turntables, almost always the Technics SL1200 with pitch control and fast start/stop. Nowadays this can be done in software. From a music collection on harddisk with controls to mix 2 or 4 tracks, with effects, equalizer and speed control. The modern DJ has a laptop! I soon found out there is open source DJ mixing software that supports Linux! Mixxx - Free DJ Mixing Software App is open source and multiplatform. And it is available as an Ubuntu package so I gave it a spin (pun intended). Only having one audio device is 'supported' but it took me some trying to find a setup where I could work 'split' with a master mix in one ear and a headphone mix in the other. So I loaded some music and tried to make it into a bit of a DJ mix. I'm not very good at it, but I enjoyed trying. Mixxx really prefers Jack audio since it likes having a lot of audio channels. I tried installing Jack audio in linux but couldn't get it to do what I want fast. Mixxx also supports the Alsa drivers and I managed to also set it up to route the main audio to a USB audio device and the headphone audio to the internal headphone jack. But I had nothing connected to the USB audio device and I didn't want to annoy my family with the noises of trying to make a good cutover from one song to the next. Mixxx has an option 'Split' to play the master output to one ear of the headphones and the headphone output to another, this is good for practicing. Control of all the mixing functions in Mixxx can be done with mouse and keyboard, but the good part is it also supports all kinds of hardware DJ controllers. And some of them aren't too expensive... and available on the second hand market for an even better price.
2023-08-09 Asking nicely for LoTW confirmations, and getting Northern-Ireland confirmed
As I am working towards getting 100 countries confirmed in morse I do keep an overview of countries I have at least one contact with which isn't confirmed yet on Logbook of The World (LoTW). On LoTW a contact is only confirmed when both sides upload a signed log with the same contact. Yes, LoTW uses X509 certificates and signing, they just hide it mostly from the user. So when I have a country in the log where I'd like to get digital confirmation I follow a few steps: I first check the page for the callsign on qrz.com. Most radio amateurs maintain a presence on that site and may mention their policy for confirming contacts. Especially for rare entities where other radio amateurs will be interested in getting those entities confirmed. If that page doesn't answer this question the next step is to check the call (or calls) with the 'find call' option in LoTW. Here it is possible to see what the last time is a log was uploaded and processed for that call. Or it shows that the call isn't active on LoTW at all. In that case I stop searching. Using LoTW is somewhat complicated and I don't feel the need to convince someone to start using it. If the amateur is active on LoTW I try to guess whether regular uploads can be expected. Some have not uploaded anything in years, others seem to upload once a year in the month of January. Or the amateur uploads somewhat irregularly. Now I am nearing 100 countries confirmed in morse I do sometimes write an e-mail to the amateur asking to confirm the contact if I haven't seen confirmation after a few months. With all the details needed to find the contact in the log so they only have to do minimal work to look up the contact.
Getting Nothern-Ireland confirmedIn amateur radio Northern-Ireland is a separate entity and I had a few morse contacts with stations in Northern-Ireland in the log but none confirmed, not even after 3 months. So I mailed two of them which are regularly active on LoTW. The first one responded after a few days with a screenshot of the confirmed contact. So now I have 91 countries confirmed in morse on LoTW. The certificate for 100 countries in morse is getting closer!
2023-08-07 Trying to understand bonnie++ output
In preparation for a migration at work I wanted to do actual benchmarking of Linux filesystem performance. I think I used bonnie in the last century, so I gave bonnie++ a spin for this. I have little idea of what 'good' or 'bad' numbers are from bonnie++. I could only compare a "local" filesystem with an NFS filesystem. I use local in quotes because this was in a virtual machine, so it's SSD storage in raid-1, with LVM on top of it, with a logical volume assigned to a KVM-based virtual machine, which uses the virtio disk driver for an ext4 filesystem. The numbers for the "local" filesystem:Version 1.98 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Name:Size etc /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP gosper 32G 809k 98 440m 38 215m 22 1590k 99 410m 30 4639 135 Latency 25688us 317ms 143ms 9332us 39208us 2089us Version 1.98 ------Sequential Create------ --------Random Create-------- gosper -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ Latency 488us 684us 762us 236us 87us 262us 1.98,1.98,gosper,1,1691401899,32G,,8192,5,809,98,450230,38,220385,22,1590,99,419827,30,4639,135,16,,,,,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,25688us,317ms,143ms,9332us,39208us,2089us,488us,684us,762us,236us,87us,262usAnd for NFS, a Synology NAS with spinning disks in raid-5:Version 1.98 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Name:Size etc /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP gosper 32G 1054k 98 78.7m 7 68.4m 13 1483k 99 109m 10 432.2 12 Latency 11138us 408ms 13261ms 16434us 212ms 274ms Version 1.98 ------Sequential Create------ --------Random Create-------- gosper -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 16384 10 16384 16 16384 15 16384 9 16384 18 16384 15 Latency 69194us 53194us 98927us 69144us 1240us 94317us 1.98,1.98,gosper,1,1691398200,32G,,8192,5,1054,98,80605,7,70058,13,1483,99,111574,10,432.2,12,16,,,,,705,10,16184,16,2800,15,693,9,3703,18,2226,15,11138us,408ms,13261ms,16434us,212ms,274ms,69194us,53194us,98927us,69144us,1240us,94317usNow I am somewhat confused. Sequential write to NFS is slightly faster.
Update 2023-08-08At work I got different but comparable numbers for iscsi attached storage versus vmware storage (and the layers in between). Those numbers helped make decisions about the storage.
2023-07-26 New countries confirmed in morse
Thanks to my participation in the IARU HF Contest 2023 and my participation in the preparation period just before the CQ WPX CW Contest I now have two new countries confirmed in morse: San Marino and Argentina. This brings me to 90 countries confirmed in morse. This proves again that contests are a way to get more countries in morse in the log and confirmed.
2023-07-09 I participated in the IARU HF Contest 2023
This weekend was the IARU HF World Championship contest and I was planning to participate. This is one of my favourite contests. I made sure the software was all set up correctly before the weekend. This year the IARU-HF contest is also the World Radiosport Team Championship, this edition in Bologna, Italy. I see 58 stations active in the WRTC, I have 41 in my log. I participated on the 10, 20 and 40 meter bands, I had no access to 15 meter this time. In total I made 212 contacts, all in Morse. The results according to my contestlogger:Band 160 80 40 20 15 10 QSO 0 0 18 170 0 24 Mult 0 0 14 33 0 9 Pts: 654 Mul: 56 Score: 36624Only a few contacts were outside Europe, not a lot of DX this time. Local interference on 20 and 40 meters limited me to stronger stations. I called CQ on the 10 meter band for a while since I was able to hear returning signals in the noise, that only gave me one contact, but with a station at the World Radiosport Team Championship, so that was cool. The log submission website gives the calculated score as Raw Score: 566 Qpts x 56 Mults = 31,696 (212 QSOs) so just like last year I still have to look at the calculations.
2023-07-07 I will participate in the IARU HF contest this weekend
This weekend is the IARU HF contest and I will participate. This year it is extra special because the IARU HF contest is also the World Radiosport Team Championship which is in Italy this year. I will try to get the WRTC calls in the log, but I'm also looking forward to getting contacts all over the world. I will concentrate on morse and maybe get some phone contacts too.
2023-07-05 Writing to new Mifare Ultralight tags
My earlier failure with an RFID T5577 tag that came with the proxmark3 made me order a bunch of new ones via 10 Pcs T5577 writable RFID tag and while I was browsing that store I found 100 pcs ntag213 NFC sticker and I had some ideas for Mifare Ultralight tags, starting with failing to convert used public transport tickets to NDEF tags. Today the package came in and the first thing I wanted to do was set up an Mifare Ultralight as NDEF tag. The fun part is the tag was already set up that way, so with NXP tagwriter for Android it was really easy to put a data set with an URL on a tag. Full log below. The downside is that the tag can't be reset to use for other things than NDEF tag, since the NDEF identifier is in the one-time-programmable bits. An attempt to zero out these bits on a tag indeed failed. Reading the NT2H1311G0DU datasheet makes me realize this is as intended and matches the 'ntag213' in the description. The fun part is that scanning the tag with my samsung phone opens the url, no questions asked. This behavior inspired me to set up a tag to link to the 2023 version of the Rickroll. I see security implications from just opening a URL without letting the user decide whether this is a good idea.Read the rest of Writing to new Mifare Ultralight tags
2023-07-01 New entities in the log: Vietnam, Ducie Island and Cayman Islands
I'm always looking for new entities in amateur radio to contact. Sometimes they happen because I knew amateur radio activity was going to happen from that location, and sometimes it's just because I notice a new country when looking for contacts on the radio. The recent contacts to Vietnam and Cayman Islands were of the latter category, just checking for available contacts in FT8 and noticing a callsign from a rare (for me) entity. Ducie Island was clearly of the former category and I checked for a time when I could get them in the log. When I got the contact, it went easier than I expected! Ducie Island is of the very rare category, and a special kind of activation as described in VP6A – Ducie Island - DX-World. The minimal amount of equipment was set up on the island in waterproof boxes with radio's and connected antennas. It was powered with a generator and a few operators retreated to a boat nearby so they did not have to camp on the island or clean up. The other operators weren't even nearby but operated the equipment remotely via satellite Internet. This may seem 'cheating' but the radio and antenna making the contact are in the DX location, the person operating it is just somewhere else, limiting impact on the location. Especially with islands that are nature reserves and have really strict rules about people visiting the island can benefit from this approach.
2023-06-30 Trying to recycle mifare ultralight cards as NDEF tags.. and failing
While working with the other NFC tags I had a crazy idea: what if I can 'recycle' used one-time public transport tickets as NDEF tags. The one-time public transport tickets are mifare ultralight tags just like the touchatag tag.Read the rest of Trying to recycle mifare ultralight cards as NDEF tags.. and failing
2023-06-29 RFID cards and the proxmark3: skidata ski card from Geilo Norway 2015Items with tag english before 2023-06-29
In March 2015 we went on a ski trip to Geilo ski area in Norway. And I kept two ski cards. Time to analyze them with the proxmark3.Read the rest of RFID cards and the proxmark3: skidata ski card from Geilo Norway 2015[usb] pm3 --> hf search 🕖 Searching for ISO15693 tag... [+] UID: E0 16 24 66 07 50 CE 09 [+] TYPE: EM-Marin SA (Skidata); EM4233 [IC id = 09] 23,5pF CustomerID-102 [+] Valid ISO 15693 tag found [usb] pm3 --> hf 15 info [+] UID: E0 16 24 66 07 50 CE 09 [+] TYPE: EM-Marin SA (Skidata); EM4233 [IC id = 09] 23,5pF CustomerID-102 [+] Using UID... E0 16 24 66 07 50 CE 09 [=] --- Tag Information --------------------------- [=] ------------------------------------------------------------- [+] TYPE: EM-Marin SA (Skidata); EM4233 [IC id = 09] 23,5pF CustomerID-102 [+] UID: E0 16 24 66 07 50 CE 09 [+] SYSINFO: 00 0F 09 CE 50 07 66 24 16 E0 02 00 33 03 02 [+] - DSFID supported [0x02] [+] - AFI supported [0x00] [+] - IC reference supported [0x02] [+] - Tag provides info on memory layout (vendor dependent) [+] 4 (or 3) bytes/blocks x 52 blocks