Electronics – Page 2 – Geronimo/370

Resonance frequencies

Posted on2021-12-042021-12-041 Comment

In the HAM course I am following to become a licensed radio amateur, the topic of resonance frequencies came along. To wrap my head around it I did some experimenting. You can find the result below. I have an assortment of capacitors and coils that I can use for these… Read the rest

HAM-gadget (6) – adjustment & enclosure

Posted on2021-11-132021-11-13

In this version I built in the possibility to adjust the summer and wintertime offset from UTC. It’s a very crude offset, I just add or subtract the offset from the UTC hour. Have to think of a better way to do this… Enclosure I built in the gadget in… Read the rest

HAM-gadget (5) – menu structure

Posted on2021-11-072021-11-08

This weekend I built in a menu structure into the HAM-gadget. Also I created a possibility to store and retrieve settings to the ATMEGA328P’s EEPROM, so they are saved for the next time you switch on the device. For now, you have to retrieve them manually, but that’s quicker then… Read the rest

HAM-gadget (4) – keyboard added

Posted on2021-11-052021-11-06

After a lot of fiddling, trial and errors, I finally got the matrix keyboard to work. Also, as the project has passed the prototype stage, I threw together everything on a PCB in preparation for mounting it in a casing. Note to self:next time first cut the PCB to size… Read the rest

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