14 Mar 19 – Arduino Update by Martin, M0XMP

The evening began with a YouTube video by Randy, K7AGE who gave part one of his introduction to Arduino.

Martin then followed with an explanation of what he wanted to achieve and how he went about it.

On display was a large Mag-loop aerial and it was pointed out that tuning by hand wasn’t an option, not only because it’s not healthy to be near a transmitting loop, but that the tuning changes when the operator moves away from the aerial. Martin produced an ordinary TV remote handset and explained how he used the Arduino to decode the output from each button. That output was then used by the Arduino to control a stepper motor which turned the tuning capacitor and thereby achieved a degree of remote control. Martin explained the programming needed to achieve this outcome. However, he felt the tuning didn’t have the feedback necessary for fine tuning as he listened to the background noise rising and falling on his rig. He did admit to have previously tried using a servo to turn the tuning capacitor and felt that offered a better feel to achieve resonance since using a knob for tuning in place of the TV remote offered better feedback.

Martin felt that both methods had led to considerable scope for experimentation in mechanical and computer science.

7 Mar 2019 – Making your antennas work

This evening’s discussion was all about how members choose and maintain their antennas. A variety were talked about. Most members are using wires, either dipoles, doublets or untuned and tuned lengths, but there was one notable inclusion of two verticals which were home brewed by spiral winding wire around  the vertical support and feeding above ground level and having sloping radials. This has proved to be a very successful arraignment for working real DX with low power.

For maintenance, various products were suggested for anti-corrosion connections and protection against moisture ingress.

Discussions continued through the tea break before members headed for home.

28 Feb 2019 – Background Noise, a discussion

It seems that most amateur radio operators experience noise or QRM at some time or another. Fortunately, most is short lived and can be tolerated, however, some interference can be more destructive and blocks out all transmissions. Those need to be found and dealt with, if possible.

Members took turns describing their problems and, at times, playing sound samples. Methods used to minimise noise and interference were discussed. This discussion has resulted in more input and participation from members than any subject so far.

Next week’s subject is almost a follow on from this, when we will discuss how to Make Antennas Work.