I had my 10-foot magnetic loop antenna ready to go for this weekend’s ARRL SSB contest, but realizing that it would only work one band (20 meters) for that contest, at the last minute I decided to build a new loop to finally go on the air as K7HKR. I used this on-line calculator to figure out something optimized for both the 20- and 40-meter bands with the high-voltage variable capacitor I have on hand. This ended up being a 15-foot circumference loop made out of 1/4″ copper coil pipe, which is much easier to bend than the 1/2″ pipe I used for the 10-foot loop.
I’ll write up a more detailed report later, but since I hadn’t tested either loop at more than 5 watts, I decided to stick with that and do the contest in their single-operator QRP category. Since this was my first contest (and first time operating on HF), I spent a lot of time just listening. However, I was enormously pleased at the successful contacts I made. In 4 hours on 40 meters during the overnight, I worked Michigan (twice), Kansas, and Maryland! Then, in the 4 hours leading up to lunchtime on 20 meters, I worked Texas (three times), South Dakota, Maryland, Montana, and Washington state. I was only responding to strong CQ calls (around S8 or better), and I failed to be heard by a bunch more east coast stations. Given that the contest is dominated by higher power stations, I knew that I would have to hear a station well for them to hear me at all (I usually had to repeat something, and I may have botched one of the QSOs), but I was surprised to make 4 successful QSOs east of the Mississippi River. The Maryland QSOs were approximately 2000 miles away, and based on the calculated antenna efficiency, I was likely radiating less than 1 watt for the 40-meter one!