It’s been a while, but I finally have put together another video. It starts a new series on small transmitting loops (“magnetic loops”), the workhorse type of antenna at my station. These antennas are a great option for working on HF when you have very limited space. Part I of the series gives introductory information and how to do the calculations to design a loop that works for your situation. Later videos will show how to build and use this type of antenna.
I’ve been thinking about ways to get on 160 meters with my very limited space for antennas. I use small transmitting loops (“magnetic loops”) to cover from 80 meters to 10 meters. These loops are tuned by the amount of inductance of the loop and a variable capacitor. The frequency scales as the reciprocal of the square root of the inductance/capacitance product. Thus, the obvious options were to build a larger loop to get more inductance, and/or use more capacitance. Continue reading
I finally finished off the 6-meter Yagi project and got it on the air. I’ve actually been using it for a while, but needed the ARRL VHF contest to get enough activity on the band to shoot video in a reasonable amount of time showing me making QSOs. I was running 50 watts into the 4-element Yagi and worked sporadic-E clouds to 30 different Maidenhead grids, including two in New Hampshire, which were my first double-hop sporadic-E QSOs. Enjoy!
I didn’t do any major stuff over the weekend, just working a couple special event stations that I heard, a couple contacts for the Montana QSO Party, and a few more for Winter Field Day. Continue reading
Now that I’ve been working on ham radio antennas, I have a couple of projects for the video blog. The first one is a 6-meter 4-element Yagi. It is designed to be semi-portable, and for me this is particularly important because it’s not practical for me to leave up an antenna for any significant length of time. Perhaps impudently, I am posting this introduction and design video before I actually have the antenna on the air! However, I have tested the antenna itself (sans 1:1 balun) with a VNA and it seems to behave more or less as expected.
I spend a lot of time talking about various design parameters and the actual modeling procedure, so this may seem a little dry if you’ve done this before. But, I try to keep my speech pace relatively slow on these videos, so there’s always the 1.25x and 1.5x speed options on YouTube. Part II will detail the construction process, and Part III will show testing and hopefully actual on-air performance.
Okay, now for the more extended story concerning the beginning of my true amateur radio operating “career”. Continue reading
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. Continue reading