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
It’s been a while since I posted because I keep getting into the mindset that I need to make all the posts highly detailed. But, I’m going to try to post smaller things more often.
With such low solar fluxes this year, activity above 20 meters has been fairly limited. While working the second day of the Texas QSO Party, I saw on the DX spotting sites that 15 meters was open across the Atlantic from the eastern US. The better news was that the opening was actually extending out West.
For this episode, I shot about 2 hours of video of me casually working the 20-meter band on a Saturday with a contest and two state QSO parties in progress, editing the video down to under 30 minutes. I comment on what I’m hearing, make a few domestic QSOs, one QSO with France, and unsuccessfully work Italy. All with 80 watts into a homebrew magnetic loop antenna. 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
I’ve been spending a lot of time coming up with a good way of motorizing the tuning shaft of the vacuum variable capacitor, and make the whole assembly modular so I can move it from one loop antenna to another to optimize a particular band. I only ended up using one antenna during the 12-hour NA QSO Party on Saturday, but it generally went pretty well. 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.