SYS: ONLINE|UTC --:--:--|BAND: Station infrastructure
SWR: 1.2PWR: 100WQTH: EN52
Power & Grounding

Power Supply

Clean regulated DC for the station, sized for the current the radio actually draws.

HIGH VOLTAGE — DISCONNECT BEFORE SERVICING. Antennas, feedlines and power supplies can hold dangerous voltages and carry RF at full transmitter power.
Power Supply engineering reference drawing
Specification summary
Output voltage13.8 V DC nominal, adjustable on better units
Continuous currentTypically 20-30 A for a 100 W HF station
Ripple and noiseBelow 5 mV RMS for a linear supply; switching supplies vary
RegulationLoad regulation better than 2 percent
ProtectionOver-current, over-voltage and thermal shutdown
MeteringVoltmeter and ammeter, or a combined display
CoolingConvection for linear, fan for switching and high current
Stage: Power
V: 13.8 VI: 30 Aripple: <5 mVreg: 2%

Overview

Amateur transceivers are built to run from a nominal 13.8 V DC supply, which is the voltage of a charged 12 V lead-acid battery. A mains supply converts AC to that voltage and holds it steady as the load changes.

Two numbers matter. The continuous current rating must exceed the radio current at full transmit power — typically 20 to 22 A for a 100 W HF transceiver — with headroom. And the ripple must be low, because a noisy supply puts hum and hash on your transmitted signal that no amount of DSP can remove.

Bands and modes

Band coverage

Station infrastructure

Modes

All modes

Safety note

A mains supply contains voltages that can kill, and its reservoir capacitors stay charged after the mains is removed. Never open a supply that is plugged in, and never assume a supply is safe because the switch is off.

Using it well

  • Size the supply for continuous transmit current, not average current.
  • Measure the voltage at the radio terminals under load, not at the supply.
  • Keep the supply ventilated and clear of the radio stack.
  • Bond the supply chassis to the station earth bus.
Reference material for educational use. Nothing on this page is a recommendation to buy a particular product, and no communication distance or performance is promised. Confirm figures against the equipment you actually have and against the regulations that apply where you operate.
Related

References that go with this one

Battery Bank engineering reference drawing
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Stored energy for portable work, field days and when the mains fails.

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HF Transceiver engineering reference drawing
Setup

HF Transceiver

The main station radio: 160 through 10 metres, all-mode, 100 W class.

f: 1.8-30 MHzP: 100 W
Transceivers→
Ground Rod engineering reference drawing
Power

Ground Rod

The station earth electrode — the reference everything else bonds to.

L: 2.4 mR: <5 ohm
Power→
Multimeter engineering reference drawing
Test

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The first instrument anyone should own. Voltage, current, resistance and continuity.

Vdc: 600 VI: 10 A
Test Gear→

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