Electronics – Geronimo/370

Cleaning mixer

Posted on2021-08-282021-09-17

I have an old audio mixer (Behringer Eurorack MX 802A) laying around. It’s been gathering dust for quite a while. In the pictures you probably can’t properly see it, but it had a lot of dust on it. Today I decided to give it some TLC and clean it up.… Read the rest

Antenna Matching Unit

Posted on2021-05-012021-05-03

1. Today I came across a second hand manual antenna matching unit (an MFJ-971). It can alter the inductive and capacitive impedance of antenna’s so they match impedance of the transmitter. For a description, see this page.… Read the rest

Silencing my signal generator (2)

Posted on2021-04-182021-04-18

A while ago I lowered the voltage of the fan in my to silence my signal generator. It was better, but over time I still found it rather noisy. So today I came up with a simple solution to silence it some more. Floorboard insulation I took a small piece… Read the rest

First satellite image!

Posted on2021-03-262021-03-26

Today I captured my first satellite image with my SDR. It is a picture that was scanned by the NOAA 19 satellite (ch 1-4, northbound 10E) at 2021-3 -26 14:39 UTC. The pass took about 20 minutes. Granted, the quality is not yet very good, but when you look carefully,… Read the rest

Radio & satellite tracking

Posted on2021-03-212021-03-22

With my new SDR (Software Defined Radio) I am able to listen to radio transmission ranging from 1KHz to 2GHz. This includes most amateur bands, long wave, short wave, HF, VHF and UHF. That’s a lot of options! The radio is a RSPdx from SDRplay: I started out simple by… Read the rest

Silencing my signal generator

Posted on2020-08-302021-04-18

Waveform generator My RIGOL DG1022Z waveform generator made a lot of noise when I first switched it on. There’s a little fan in there, operating on 12 Volts. Having opened up the device, I took out the fan and tried to operate it on 9 Volts. That still worked adequately,… Read the rest

‘Datacenter’

Posted on2018-12-142019-03-23

Today I built my ‘datacenter’… Three Raspberry Pi’s that will form a stack of ‘power’ to run System/370 Operating Systems… For a full photo report see this link. Datacenter connected… Read the rest

PC to bench power supply

Posted on2018-11-30

PC to bench power supply This post describes how I made a power supply for my workbench. It delivers 3,3V, 5V, 12V and -12V. Do these voltages sound familiar to you? Read on… Power supply Color chart Connections Indicators Labels Power BOB … Read the rest

Totem – Robotic arm

Posted on2018-08-04

Totem – Robotic arm The guys at Totem sent me a sample of their robotic arm to review (link points to the mechanical version without the electronics). The version I received contains several Totem Bus modules to drive the arm. It is described on their web page as an “easy… Read the rest

Totem – Side Panel One Libraries

Posted on2018-02-21

Totem – Side Panel One Libraries Together with the guys from Totem, I’m developing libraries and classes to make use of the Side Panel 1 components. We decided, for educational purposes, to make one library per component. At Github, you can find the libraries and an example program (still under… Read the rest

Totem Mini Lab – New review

Posted on2017-12-21

Totem Mini Lab – New review As I wrote yesterday, I received a replacement Lab Board. Today I’m testing it by repeating the tests I did for the first full review. First I will give you the conclusion, the details are below the conclusion. Conclusion Improvements The idle voltage and… Read the rest

Totem Mini Lab – replacement Lab Board

Posted on2017-12-20

Totem Mini Lab – replacement Lab Board Today I received a replacement Lab Board in which the guys of the Totem team made improvements, amongst others, based upon my tests and suggestions. Here’s the contents of the package. A new test will follow: SaveSave SaveSave… Read the rest

Totem Rotary encoder – explained

Posted on2017-12-18

Totem Rotary encoder – explained How does it work? I was fumbling around with the Totem Mini Lab’s Side Panel 1, especially with the rotary encoder that s mounted on this side board. At first, I could not make heads or tails from it, but, using my oscilloscope, I’ve figured… Read the rest

TotemDuino connected to MacBook!

Posted on2017-12-14

TotemDuino connected to MacBook! After some mailing back and forth with the Totem team, they found a solution. Oddly enough, it’s a solution I tried, but it did not work the first time. It appears one has to install the Prolific USB-to-Serial drivers. Installation log Here’s what I did now:… Read the rest

Totem Side Panel 1 – rotary Encoder

Posted on2017-12-08

Totem Side Panel 1 – rotary Encoder I did some further investigation into the working of the rotary encode in the Side Panel 1. At first, I could not make heads or tails from it, but I think I’ve figured it out now. It appears that both connections – labeled… Read the rest