Top Band, as 160 meters is called, presents a a challenge because the long wavelength leads to large antennas. One can always play tricks with loading to be able to use a physically shorter length of wire. There are many articles on compact 160 m antennas, but this is not one of them. Rather, I'm [...]
Designing Self Resonant Coils for Antenna Traps and Chokes
A lowly coil of wire can be surprisingly difficult to understand and model correctly. I use coils of wire or coils of coax cable as trap inductors for various antenna designs that I have built. In the low frequency limit, the traditional inductance calculations work okay and can give you a pretty good estimate of [...]
Modeling the J-Pole
When you first meet the J-Pole, you are forgiven if you don't quite grok how it is supposed to work. What is that 'J' for anyhow? When I have questions like this, I get out the 4NEC2 modeling program, and see what it says. Let's start out with the basic model -- the J consisting [...]
A 30 Meter Bamboo Pull-up Hex Beam
The bamboo Moxon I built for the 20 meter band earlier this summer convinced me of the power of compact two element antennas. When I was showing the Moxon to a friend, he pointed up to a nearby tree and said "There's the place to pull from," pointing to the crotch of a tall branching [...]
Performance of a 20 Meter Vertical Collinear Antenna
A couple of years ago I designed this antenna which had the good property of substantial low elevation gain and the model generated consistent and predictable 4NEC2 results. The wire that it would replace was already "pretty good" so it's taken two years to decide to build it. But I always had the feeling that [...]
A Pull-up Bamboo Moxon Antenna for 20m
As much as I love all of the wires up in my trees, I've come to realize that a little real gain and directivity would be nice. However, my trees are really in the way for a a typical tower and a beam antenna, so I am left to consider what resources I have and [...]
Bees, Bears, and a Honey Flow
June 1st is a pretty good date to pick for the beginning of the main honey flow in our area. There are early nectar sources such as Big Leaf Maples, Dandelions, and fruit trees which come earlier, but the weather is not yet cooperative and the hives are not as developed yet. By June 1st [...]
COVID-19 No End in Sight
Oregon is one of the states with the lowest per capita COVID-19 infection rates. However, despite our best efforts, we are still seeing about 50 new cases per day (down only a little from a high of about 70 cases per day five weeks ago). Nothing much has changed for the last two or three [...]
COVID-19 Leadership Matters – A Tale of Two States
The response to the COVID-19 crisis has varied from state to state depending on the perceived need for aggressive action and depending on political considerations in our divided nation. As a result, the United States offers 50 simultaneous experiments in epidemiological response, often with dramatically different initial conditions, such as the high population density and [...]
Quick COVID-19 Math
Due to the scarcity of tests across the country, hospitals usually only test those cases that they need to admit to the hospital. The hospitals are not testing the majority of people complaining of symptoms, nor the many possibly infected asymptomatic people. We need to keep this fact in mind when looking at the statistics [...]
Squash Practice 