Category Archives: Electromagnetics

Feed Two 50 Ohm Antennas from One Transmitter

Wes Cardone presented at the July 2024 meeting of the Chelsea Amateur Radio Club the principles of directed energy by means of multiple antennas. The principle is that you rob from the rich and give to the poor. We decide on a pattern that we want our dual-antenna configuration to produce and then place the two antennas a defined distance… Read more »

Antenna Feedline Optimal Length for Resonance

Updated 4-18-2024 I recently discovered a YouTube video that shows how to cut an antenna’s feedline length to achieve resonance (See below). I then discovered that there are many such erroneous YouTube videos telling you that you can use “jumpers” to improve your antenna performance. There are no benefits to these practices! But this begs the question… Why? On the… Read more »

April Meeting: EZNEC Antenna Segments Made Easy

More on EZNEC at the April 2024 club meeting. Have you dabbled with EZNEC antenna modeling software (or any of the other free NEC derived antenna modeling software applications) and found it just did not work out for you? Join the crowd. At the April meeting of the Chelsea Amateur Radio Club, Wesley Cardone (N8QM) will give a third presentation… Read more »

EZNEC J-Pole Modeling (and Deep-Dive)

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A Qualitative Presentation At last month’s meeting (February 2024), we introduced the free EZNEC antenna modeling software. It was a very introduction-oriented presentation that explained what it was all about. For the March 2024 meeting (Tuesday, March 12th), we will be presenting concepts relating to what EZNEC software demands from you, the user. That is, what ratios in wire lengths… Read more »

Introducing The Rail-Pole Antenna

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Chelsea Amateur Radio Club member Wesley Cardone (N8QM) has devised an antenna topology he is calling the “Rail-Pole Antenna.” The reader may already be aware that Wes has consistently maintained that all antennas are merely dipole antennas in disguise and this one is no exception. Wes is willing to give a series of presentations to the Chelsea Amateur Radio Club… Read more »

Utility Pole Interference

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The Chelsea repeater (WD8IEL), since this trustee assumed its maintenance responsibilities in 2022, has demonstrated an attribute of performance suggesting desensitization. That is, the background RF noise has a magnitude greater than the receiver’s sensitivity. The effect is that the repeater can be heard at a much greater distance than it can be worked. BACKGROUND ELECTRO-MAGNETIC FIELD QUANTIFIED The collective… Read more »