At ED1R we use industrial ball bearings on our towers to turn the antennas. The ball bearings are reliable IF you protect them properly. We learned this lesson the hard way. After almost three years in service, I feel confident sharing our solution for adequately protecting the SKF bearings on antenna towers.

Continue reading

Sometimes household appliances cause (significant) electromagnetic interferences in our receivers. Unfortunately, replacing them isn’t always an option. Fortunately, adding common-mode chokes to the input and/or output cables can drastically reduce the emitted interferences. Choosing the right ferrite material is probably the most important success factor. In this post, I compare three different materials and show how you can measure and evaluate (random) ferrite cores by yourself!

Continue reading

The year 2020 started with outstanding tropospheric VHF propagation here in southern Germany. For the first time, I was able to copy the VHF beacon GB3NGI from Northern Irland at a stunning distance of 1300km. Read more about this great opening and listen to the audio recording I made.

Continue reading

The ST-Link/v2 is an in-circuit debugger and programmer for the STM32 and STM8 microcontroller families. Due to its capabilities, it is an extremely popular device and clones are available from your preferred Chinese trading platform for less than 5 euros. I recently ordered a few of these cheap ST-Link/v2 clones for a new project. However, making them work was pretty frustrating. Read on to learn about the problem, the symptoms, and the (super) easy fix.

Continue reading

Both ICOM radios, the IC7300 and the IC9700 allow a variable transmission (TX) delay. This comes in handy if external peripherals like amplifiers and/or pre-amplifiers are used. These devices often have slow mechanical relays. It is good practice to wait until the complete transmission chain is ready before RF is applied. Out of curiosity, I measured and verified the adjustable tx delay on both radios.

Continue reading

Author's picture

Tobias Wellnitz, DH1TW


Software Engineer

Germany