Over the last few years, I spent a lot of time simulating antennas. One annoyance I encountered over and over was the unavailability of values for ground conductivity and the relative permittivity. Two figures have quite an impact on the antenna performance, especially on vertical antennas. This finally led to the conclusion that both figures need to be measured. In early 2012 I built a measurement kit and finally determined ground conductivity and relative permittivity at our contest station.
Where ever I operate contest in a multi transceiver environment interferences between the 40m and 20m are guaranteed. An easy and inexpensive way to reduce interferences is to add coax stub filters. Dave, K1TTT has a great website with a lot of useful technical resources. One of them is dedicated to coax stub filters. After building up two sets of stub filters (one in Namibia at V55V and the other one in Spain at ED1R) it’s time to document it.
In preparation for the upcoming CQWW 160m Contests, my friend Hannes, DK1NO was so kind to give me one of his W7IUV broadband, high IP3 preamplifier. Thanks, Hannes! Without knowing the exact performance data, I ran a few measurements with my Network Analyzer on the amplifier to determine the Gain and its operational fitness. Read on for measurement results and additional notes on how to measure active components.
It finally happened… After a decade of reliable service, my Alpha91b amplifier broke. Most likely on its way to Spain one of the tubes broke. During the commissioning at ED1R, fire & smoke shot out of a chimney. The first shock was big, but a few measurements confirmed that just the tubes were broken. In this blog post, I will share the knowledge I gained during debugging, commissioning, and breathing new life into the amplifier.
This year we wanted to seriously compete in CQWW CW from the ED1R contest station. While the station is equipped reasonably on all bands with Yagis and verticals, there were no dedicated receiving antennas available - yet. Out of my former contest participation from other stations, I know that when it comes down to winning a CQWW, dedicated receiving antennas are a must-have. Beverages provide great directivity and reduce the EU clutter significantly.
Today, I could measure the performance of the well-known ICE bandpass filters. Read more about the measurement results.
Lately, I needed a 3dB splitter for an HF (1…30MHz) measurement project. Instead of buying myself a splitter, I decided to build it on my own. After measuring the performance I am satisfied with the result.
