In my opinion, this was one of the most successful rounds of the OM Activity Contest. Thanks to the SO2V mode, I was able to keep up with stations using 100W of power. Števo OM7KW decided, somewhat unusually, to start on a different frequency, and before the contest and at its start, I had a longer contact with František OM7WA, which likely ensured that the frequency or its vicinity wasn’t occupied by a station that couldn’t hear me. Franta has an excellent signal on 80m.
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How to Achieve an Excellent Signal in the OM Activity Contest?
Inverted Vee Antenna
Two decades of my observations show that horizontal loop antennas are among the best NVIS antennas. It’s no coincidence that they’re also called “cloud burners.” I consider the center-fed dipole and its variation in the form of an inverted V antenna to be the second-best antennas.
Improving the Signal by Selecting the Frequency
No, I’m not talking about tuning the antenna or its SWR within the OM Activity Contest frequency range. I’m talking about choosing a frequency so that the strongest stations aren’t near it. For example, if I choose a frequency like this for my call, it won’t be very successful. Why? Even if the signal from this station doesn’t cause me any trouble, it will cause problems for transceivers that aren’t as resilient. Therefore, it may be better to “squeeze in” to a narrower space between weaker stations than to try a spot a little farther from a strong station.
Improving the Signal by Adjusting Modulation
Frequency Response of the Behringer XM8500
Much has already been written about a high-quality SSB signal. It all starts with choosing a microphone. Don’t underestimate the importance of this choice. I’ve had good results with the Behringer XM8500 vocal microphone. This dynamic microphone has lower sensitivity, a cardioid polar pattern, and a rolled-off, narrower frequency response. It naturally suppresses low frequencies that aren’t necessary for communication over a radio, while emphasizing the spectrum above 1 kHz, thereby helping to balance the frequency response of the transmitted signal. The resulting frequency response is further modified by the radio’s circuits, primarily the equalizer, compressor, and the shape of the IF filters.
June Round of the OM Activity Contest 2024
I already mentioned that the first contact was with Frant OK7WA. Immediately after that, several more stations called. However, sometimes there would be long minutes when no one called. This gave me time to scan on my second FT-1000MP receiver. Using SO2V, I made as many as a quarter of my contacts on it!
OK7WA’s signal from the 2023 OM Activity Contest:
However, it’s impossible to stay on the frequency the entire time, and it might not even be practical. This time, luck was on my side, and I managed to make multipliers like E, thanks to Vlado OM3TLE. I also heard Slava OM0AS, but by the time I managed to call him, he had moved off the frequency, and I couldn’t find him again later. Still, a final tally of 54 contacts with 23 multipliers at QRP power is quite satisfying.