Linear vs Switching Power Supply for Ham Radio UK: Which Should You Buy?

TL;DR: For most UK ham shacks in 2026, a well-designed switching (SMPS) 13.8V supply with at least 30A peak headroom is the practical choice — lighter, cooler, and far more affordable than a linear unit of the same rating. Linears still win on absolute RF quietness in sensitive HF setups, but modern SMPS units with noise offset control close much of that gap. If your transceiver draws 20A+ on transmit, do not settle for a 5A laptop brick.

Why This Comparison Matters for UK Operators

Every few weeks on amateur radio forums, someone building their first shack asks whether a cheap AliExpress SMPS is "good enough" or whether they need a heavy linear supply like the classics from the 1980s. The concern is always the same: switching noise on receive. Operators report S-meter readings jumping from S0 to S5–S9 when a poor-quality PSU is connected, even with no one transmitting.

That fear is legitimate. A noisy supply can ruin HF weak-signal work. But the answer is not automatically "buy linear." The real question is whether your chosen supply — linear or switching — is designed for radio use, properly filtered, and sized for your current draw.

Linear Power Supplies: The Traditional Choice

A linear bench supply uses a large mains transformer, rectifier, and linear regulator to produce a stable DC output. Because the regulator drops excess voltage as heat rather than switching it on and off rapidly, the output contains very little high-frequency ripple. That is why linear supplies have a reputation for being RF-quiet.

Advantages of Linear Supplies

• Very low conducted and radiated switching noise — ideal for sensitive HF receivers
• Simple, predictable behaviour under varying loads
• Excellent transient response when load changes suddenly (e.g. SSB peaks)

Disadvantages for UK Shacks

• Heavy and bulky — a 30A linear can weigh 10–15 kg and dominate a small desk
• Runs hot — continuous heat output raises shack temperature and energy bills
• Expensive — quality 30A linears often cost £200–£400+ in the UK
• Poor efficiency — much of the input power becomes waste heat

For a dedicated contest station or a permanent HF-only setup where absolute quietness is paramount, a linear supply from a reputable brand remains a valid choice. But for most UK operators running a mixed HF/VHF/UHF station, the weight, cost, and heat trade-off is harder to justify in 2026.

Switching (SMPS) Power Supplies: Modern and Practical

Switch-mode power supplies use high-frequency switching regulators, smaller transformers, and filter stages to convert mains AC to regulated DC. They are the technology inside your phone charger, LED drivers, and most modern bench units — including purpose-built radio supplies.

The problem is that not all SMPS units are equal. A £15 LED driver or car adapter may raise your S-meter dramatically. A supply engineered for amateur radio — with proper EMI filtering, shielding, and sometimes adjustable noise offset — behaves very differently.

What Forum Operators Actually Test

Experienced operators often bench-test supplies by connecting them to a transceiver, tuning to a quiet HF frequency, and watching the S-meter on receive with no antenna traffic. Cheap adapters frequently show S5–S9 noise. Better switching units drop that to S1–S2 or lower. Some older laptop bricks surprisingly perform well at low current but fail under 20A transmit loads — the exact scenario a 100W HF rig creates.

Advantages of Quality Switching Supplies

• Compact and lightweight — easy to move, ship, and fit in small shacks
• High efficiency — less heat, lower running costs
• Affordable at high current — 30A switching units cost a fraction of equivalent linears
• Adjustable output — many units cover 9–15V DC, useful beyond 13.8V radio work

Where Switching Can Fall Short

• Cheap unfiltered units inject switching hash across HF bands
• Audible fan noise on some models (though thermostatic fans help)
• Perceived reliability concerns with no-name imports — mitigated by UK warranty and returns policies

The 13.8V / 30A Question for Ham Radio

Most amateur transceivers expect a 13.8V DC nominal feed. On transmit, a 100W HF radio can draw 20A or more; manufacturers typically recommend a supply rated to at least 30A to handle peaks, inrush, and accessory loads.

Undersizing is a common mistake. A 5.83A laptop brick may show a clean S-meter at idle but cannot sustain a full-key down transmission. Voltage sags, the radio reduces power, or the supply overheats and shuts down.

The Jaogau PS-30A 13.8V 30A bench power supply is specified at 20A continuous and 30A peak, with 9–15V DC adjustable output (factory-set to 13.8V). At £82.90 inc. VAT with free UK delivery, it targets the "affordable but radio-ready" segment that forum buyers ask about — without the weight penalty of a linear.

RF Noise: How to Decide in Your Shack

Before choosing linear vs switching, run a simple test:

1. Connect the candidate supply to your radio with a proper gauge DC cable
2. Tune to a quiet HF band (e.g. 14.050 MHz) with no signals present
3. Note the S-meter reading on receive
4. Disconnect the supply and compare — or test a known-good unit

If a switching supply shows unacceptable hash, check whether it offers noise offset adjustment. Some radio-specific units let you shift switching frequency away from a problematic band — a feature the Jaogau PS-30A advertises for HF, VHF, and UHF use.

Additional mitigation includes ferrite clamps on DC leads, keeping supply wiring away from coax, and ensuring a solid ground bond. These steps help regardless of supply type.

Linear vs Switching: Quick Comparison Table

Our Recommendation for UK Buyers

Choose linear if you operate mostly HF weak-signal modes, have a permanent station with space and ventilation, and budget allows a premium unit from a trusted brand.

Choose switching if you want 30A capability without the weight, need a supply that works for radio and workshop testing, or are setting up a shack on a realistic UK budget. Prioritise units with radio-specific filtering, adjustable output around 13.8V, and at least 30A peak rating.

For a deeper dive into SMPS technology, see our switch mode power supplies guide.

Frequently Asked Questions

Is a switching power supply OK for ham radio?

Yes — if it is designed or tested for radio use and sized for your transmit current. Cheap generic SMPS units often cause interference; purpose-built 13.8V radio supplies with proper filtering and noise offset features are widely used in UK shacks.

Will a linear supply always be quieter than switching?

Generally, linears produce less high-frequency noise out of the box. However, a well-built switching supply with EMI filtering and noise offset can perform acceptably on HF, VHF, and UHF. Always test in your own shack before committing.

How many amps do I need for a 100W HF transceiver?

Plan for at least 20A on transmit, and choose a supply rated to 30A peak for headroom. The Jaogau PS-30A provides 20A continuous and 30A peak at 13.8V, matching typical base-station requirements.