Posted on

20200429

Oh.. What a weird and wonderful night. I was exited about assembling the walky-talky modules and went on imagining of scenarios I could use them in. An idea gloomed.. What if the module would work in FM domain? I’ve been making radio experiments with my raspi (see Hammeradio) and the itch to send wireless signals is an old one. The question led me on a frantic internet search stream and eventually I run into a website I visited years ago: Polimorphous Space by Tetsuo Kogawa. I learned about the site from Diego Cruz Martinez an activist/engineer who worked for/with Radio Oaxaca. I interviewed him when I was working for M2Hz and the interview in available Finnish: Ääni intiaanikylille (2009).

Kogawas site is fascinating. There are texts and interviews dealing with the work of Félix Guattari (whom Kogawa met in 1981), manifestos and poetry, bundled with technical notes and schematics. The radio art guides he offers are thorough and the radio transmitter builds seem very robust. Here is a quote from his Micro Radio Manifesto (2006).

Today, our microscopic space is under technologically control and surveillance. Our potentially diverse, multiple nad polymorphous space is almost homogenizee into a mass. Therefore we need permanent effort to deconstruct this situation. In order to do this, to use a very low-power transmitter is worth trying. Small transmitter can be easily made by your own hands. [SIC]

This is a direct call for action and aligned with the texts he offers, this sets a clear trajectory for critical radiophonic work! The looks of his builds are wonderful. He uses an adaptation of “Manhattan style” method in his circuit construction (some notes on the style on Parasit Studio blog). The name Manhattan style reflects the street grid and urban planning of Manhattan, New York and I guess it links to the era of the Manhattan project too.

I’m now dreaming of building an eurorack unit of “the standard model” transmitter in Manhattan style. Some components are rare (2SC2001 transistor) but he also offers plans with alternative components (BC337 transistor). I imagine that in a rack the transmission would cause a lot of noise and interference but the build is conceptually firm. I think that as a module it reflects and is a call for the “responsibility of speech”. I’ve come to believe we have a responsibility to make sound, to voice opinions so that we do not collide to each other. This idea is well drafted in a boating story I heard from Topi Äikäs. In short: “If everybody is silently looking for the truth, nobody is safe!”. I could etch this story on the PCB.

After an exiting couple of hours in the world of Kogawa, I realized that the module should also include a receiver: Whats would be the point in making noise if no-one can listen to it. After some search I found this Simple FM Radio build (credited to Charles Kitchin) which is simple and runs on the same voltage as the transmitter (the unit in the photo is also build in Manhattan style). This means both builds could be powered from the same supply! I’ll have to experiment if this will cause too much interference but the idea is clear. The module could have one input for transmitting and one for receiving. With two modules, two (or more) racks can be made to work in unison.

An additional bonus in the transmitter build is that I could use DIY mineral water capacitors (which I experimented with on the Simple EQ build) for setting the transmission frequency (it needs a variable capacitor between the values of 10 to 20pf). This is perfect because when working on the walky-talkies I felt horrible remorse for not continuing to develop/build modules I’m planning to use in upcoming mineral water performances. Suddenly a side quest to radio transmission domain proofs meaningful and everything makes sense for a while.

Posted on

20200428

Build a set of walky-talky eurorack modules which accept modular level signals trough their electret microphone inputs. To accomplish this I assembled a line level signal to microphone input adapter (following this guide: 20 dB PAD for line to electret microphone input) and included a 47k resistor before the 10uf capacitor. The walky-talky speaker output is routed to a tl071 based line level to eurorack level amplifier (I followed the TrAniModule line1-lineout design). The push-to-talk button is routed to a switch which is mounted on the panel. At first I powered the walky-talkies using 7805 chips (build heat sinks from salvaged aluminum) but they run quite hot so I replaced them with LM2596 buck converters. This also dropped the consumption from 200mA to around 80mA (~2mA on the negative rail) but this is dependent on the amount of signal amplification the units uses (which seems to be a automated process, based on some kind of feedback between the devices). The power supplies have reverse-polarity protection. I got the idea for building them from a youtube video.

The sound is interesting, like in megaphones but they are still unstable. One feature of the unstable behavior is that in some tests, some frequencies of sine waves would cause the unit to glitch and go silent. Once a different frequency is transmitted the connection is re-established. Very high frequencies cause a morphing glitchy interference space. The units distort sounds in interesting ways, almost like wave folders and I can also pass clock signals trough. Bass drum tones get removed but low frequency clicks pass. I think the glitches are a power-supply issue (my bench power-supply is very noisy), also there are a lot of loose wires and dodgy connections. I’ll rework the connections and set the rattling wires with hot glue, after I receive on-off-(on) switches (I’ll use them for the push-to-talk button). Also had the idea of adding voltage to control the push-to-talk button but it wouldn’t work as the devices make a loud beeb every time they establish a connection. When nothing is inserted to the input the microphone can be used.

The walky-talkies are Exibel FX-27’s, which we got from Kiasma and used with the xxx_group back in 2009. They have been collecting dust for 11 years! They have 8 channels and I’m currently using 446.00625MHz (the same as baby monitors, which I can now use as inputs for my modular!). I’ll have to wait until the libraries open to laser cut pretty faceplates for them and I also want to mount their antennas properly. Currently the PCBs are attached on a dodgy plywood sheets and the antennas are located in the back. They look like bombs. Sending wireless signals has been a longtime fascination. The last time I’ve worked with wireless audio of this type was in 2006 when we established Storijapan with Kristian (a layout of the our wireless setup is still on our server homepage). Transmitting signals from and in a eurorack system feels like a dream I had a long time ago.

Posted on

20200424

Paul Wilson: Pure humour without jokes in 1970s Prague (2014) David Vaughan. The radio show deals mostly with the writing of Václav Havel. Crusaders’ School of Pure Humour Without Joke is mentioned briefly. There are some notes on The Plastic People of the Universe (rock band established in the fall of 68). “They didn’t want to have anything to do with politic, so at the time this became a strong political statement.” Says Wilson, who became a singer of the band, because they wanted to perform their répertoire in English.

Posted on

20200421

The UNIX Operating System (1982) Bell Labs. A clear explanation on now unix computers are structured and organized. Really interesting to see how particular languages and hierarchies are enforced by their design.

Traded my Kastl 1.5 to a A-137-1. My first Doepfer module!

Posted on

20200416

A brilliant initiative for easing the pandemic-art-grant writing pressure: UK Artist Grant Writing Support (2020).

UK Artist Grant Writing Support is a network of artists, curators and producers working in contemporary art organisations, who are coming together to provide in-kind support to artists requiring help with emergency grant applications.

Care in times of Care (2020) Staci Bu Shea. I read this as a critique of liturgical inclusiveness performances. By default all inclusive gestures are good, we are all learning and experimenting how to deal with our privileges. I think the article does a good job in presenting care as dynamic and conflictive process. Caring can and perhaps should lead to change in both parties, which can be really hard.

Do we need another event or text on care without the necessary institutional and organizational change that could really respond to such uncaring times?

For care to be preventive is not to say that conflict would be avoided. Rather it anticipates the experiences and needs of the other as opposed to reactionary care which is a response to uncaring conditions.