Chelsea Theory Presentations

Characteristic Impedance

What the heck is characteristic impedance, anyhow? We know that, for example, a typical coax feed line has a 50 Ohm “characteristic impedance,” but you won’t get that measurement with a DMM.

You will be amazed at what you can grasp once you understand what a characteristic impedance represents and how it does it.

Why Coax and Not Hookup Wire

Did you ever wonder what the magic formula was for when to use coax and when ordinary, everyday hookup wire is okay to use? Join the crowd. But look in here for a little clarification.

The Near Field” What’s That?

We all know about an antenna’s electromagnetic radiation to the four corners of the globe. But few realize that the radiation is made of two components: 1. the far-field; and 2. the near-field. Read here how those two fields are distinguished.

Phasing Vertical 1/4 Wave Antennas for Directivity

This web page looks at the phasing of vertical pairs for electromagnetic directional control.

QEX Publication: LTSpice Diode Characterization

One of Chelsea’s very own, Wesley Cardone (N8QM), has been published by the ARRL May 2023 QEX journal.

Wes is considered an industry expert regarding conserved analog conservation and has extensive knowledge and many years of experience to that end. This includes:

Wes has agreed to give a presentation at the 2023 Chelsea Radio Club swap meet coming up on the first Sunday of June this year.

Your comments are warmly accepted. Wes will try to respond to what he can.

Modeling the J-Pole Antenna for Computer Simulation

Two approaches are given. The first will be introductory in nature, covering the topic from a qualitative perspective. The second will be a deep dive where a basic understanding of electromagnetics is required.

Qualitative Presentation

Deep Dive (coming soon, 3-12-2024)