Section · Antennas

📶 Antennas

DIY antennas and measurements: ground plane, collinear, balcony mount, SWR.

Antennas

DIY 1/4λ ground-plane antenna for 70 cm: calculation, soldering, tuning by SWR

A cheap and honest antenna for a hotspot or base station: the length formula, four radials, and tuning the SWR down to 1.1.

⏱ 9 min★★☆
Antennas

Balcony and rooftop antenna for 70 cm: J-pole, collinear, mounting and lightning protection

Getting the antenna up higher = dramatically more coverage: J-pole/collinear, choosing the cable, mounting, and the lightning protection you can't skip.

⏱ 11 min★★★
Antennas

NanoVNA: how to measure SWR and tune an antenna

A cheap vector network analyzer: calibration, measuring SWR and resonance, finding a cable break — and how not to fry the device by transmitting into it.

⏱ 9 min★★☆
Antennas

Collinear antenna for 70 cm: calculation and build from coax

A high-gain antenna made from sections of coax: in-phase segments, length calculation with the velocity factor, and tuning by SWR.

⏱ 11 min★★★
Antennas

SWR and antenna matching: how to read the graph and what to do about high SWR

SWR in plain words: reflected power and why a high SWR heats things up and can burn out the final stage. How to read the graph, the causes of high SWR, and what to do — trimming, connector, cable, radials.

⏱ 9 min★★★
Antennas

Stock antenna or Nagoya NA-771: is it worth swapping

The stock “stubby” versus the long Nagoya NA-771: does the swap give a real gain, how to avoid buying a fake, and when the antenna matters more than power.

⏱ 7 min★☆☆
Antennas

Coax for 70 cm: RG-58, RG-213 or LMR-400

Where the signal is lost on the way to the antenna: losses in RG-58, RG-213 and LMR-400 at 433 MHz, feedline length and connectors. Which cable to choose for a remote antenna.

⏱ 9 min★★☆
Antennas

SMA, BNC, PL-259 and N connectors: what goes where and how not to mix them up

Antenna connectors explained plainly: SMA male/female (watch out for Baofeng!), BNC, PL-259/SO-239 and N-type. Where each one belongs and what's wrong with adapters.

⏱ 8 min★★☆
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