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Test equipment — edited Aug 31, 2026 by Unknown editor
This is the first recorded version, so every line is shown as added. Note: Imported from content/wiki
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You can build a working station with no test gear at all, and diagnose almost nothing. A short list
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of inexpensive instruments turns guesswork into measurement.
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## Buy first
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- **Digital multimeter.** Any $30 meter with continuity, DC volts and resistance. Most station faults
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are a bad connection, and continuity finds them.
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- **Vector network analyzer.** A NanoVNA-class analyzer costs less than a length of good coax and
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measures SWR and impedance across a whole band, so you can see whether an antenna is short, long or
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simply not resonant where you thought. It also measures cable loss and finds the length of an
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unknown coax run.
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- **Dummy load.** Lets you test, tune and measure without radiating. A 100 W load is enough for
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anything short of an amplifier.
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- **Directional wattmeter.** A meter that reads forward and reflected power separately, so you know
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whether a high SWR reading is the antenna or the meter. Cross-needle types show both at once.
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## Buy later
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- **Antenna analyzer with a built-in display** if you prefer to work up a tower without a laptop.
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- **Oscilloscope.** A cheap digital scope is for audio, interfacing and power supply ripple, not RF —
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useful for building and repairing, unnecessary for operating.
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- **RF current clamp.** Shows common-mode current flowing on the outside of your coax, which is the
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real cause of most "RF in the shack" and computer-interference complaints.
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- **Signal generator and step attenuator.** For receiver comparisons and direction-finding
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practice.
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- **Power supply with current limiting** for bench work, so a wiring mistake blows nothing.
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## Common measurements
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- **Is my antenna resonant?** Sweep SWR across the band with the VNA. The dip tells you the resonant
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frequency; an antenna too long dips low, too short dips high.
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- **Is my coax bad?** Terminate the far end in a dummy load and measure loss. Compare with the
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manufacturer's figure for that length and frequency; more than about 1 dB extra usually means water
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ingress or a failed connector.
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- **Is that noise mine?** Kill the house breakers one at a time while listening. Half of all "band
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noise" is inside the building.
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- **Is the radio putting out?** Into a dummy load, measure power on each band. A single dead band
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usually means a relay or filter, not a final.
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## Borrow rather than buy
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Clubs are a better source of test equipment than a credit card. Spectrum analyzers, service monitors,
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tower-mounted analyzers and calibrated loads are exactly the things a club should own and members
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should share; a "test equipment night" is also one of the better meeting programs going. See
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[starting a club](/wiki/clubs/starting-a-club) and
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[club resources](https://usnara.org/clubs/resources).