Tag: antenna theory
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Building a 49:1 Transformer for a 40m End-Fed Half-Wave Antenna
The end-fed half-wave presents a nasty impedance to match. Here’s how to wind the 49:1 transformer that tames it, and build the 40m wire to go with it.
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Choosing Coax for HF: Efficiency, Length, and Cost
Coax is not just a wire that connects your radio to your antenna. The type and length you choose affects efficiency, cost, and your whole operating experience. Here is how to think about it.
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NVIS vs. Vertical DX Antennas: Two Completely Different Jobs on the Same Bands
Same bands, opposite goals. Here’s how NVIS and vertical DX antennas actually differ, and how a low-mounted 40m EFHW can blanket a state like Arizona.
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GMRS Antennas: What Actually Improves Your Range
More watts get all the attention, but antenna height and gain do more for your GMRS range than a bigger radio ever will. Here’s what’s actually worth upgrading.
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The Random Wire Antenna: Magic Lengths, Lengths to Avoid, and the Right Transformer
A random wire antenna is one of the simplest, cheapest ways onto HF, but the length you cut it matters more than most people realize. Here is what actually makes one work well.
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Stealth Antennas for HOA Neighborhoods: What Actually Works
An HOA restriction does not have to mean giving up on a real home HF antenna. It means getting more creative about what a real antenna is allowed to look like. Here is what actually holds up.
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How to Tune a Vertical Whip Antenna for HF
Verticals live and die by their ground system, not just their length. Here’s the actual process for getting a whip resonant on the band you want.
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Permanent Wire Antenna Installs: Lessons From My Backyard
Everything I built for portable use eventually taught me something different once I tried to leave it up permanently. Here is what actually held up in my own backyard, and what I would do differently.
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What I’d Buy Instead of the Chameleon MPAS 2.0
A modular HF portable antenna kit that beats the $625 Chameleon MPAS 2.0 on both performance and price, built around the CaHR Hydra and a Spooltenna EFHW.
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Building a 1:1 Common-Mode Choke for HF
RF in the shack, unstable SWR, mystery noise: a lot of it traces back to common-mode current on your coax. A choke is a cheap, quick fix.