Part of our Building Your First Ham Radio Station guide.
Every base station radio needs a 12-13.8 volt DC supply, and the choice between switching and linear power supplies is one of those decisions that seems trivial until you are dealing with mystery RF noise across your entire HF spectrum and realize your power supply is the culprit.
Linear Power Supplies: The Old Reliable
Linear supplies, like the Astron RS series I run, use a transformer-based design that is inherently quiet from an RF perspective. They are heavy, sometimes genuinely heavy for higher current models, and less efficient than switching designs, generating more waste heat for the same output power. But that same simple, old-school design is exactly why they remain the gold standard for RF-sensitive shack use. A well-built linear supply essentially never introduces its own noise into your receiver.
Switching Power Supplies: Lighter, Cheaper, Riskier
Switching supplies are dramatically lighter and more efficient than linear designs for the same current output, and they are usually cheaper too. The tradeoff is that switching supplies work by rapidly switching current on and off at high frequency, and a poorly designed or poorly filtered unit can inject exactly that kind of switching noise directly into your HF receiver as a buzzing or hash-like interference that shows up across a wide swath of spectrum. Quality varies enormously in this category. A well-engineered, properly shielded switching supply from a reputable radio-focused manufacturer can be nearly as quiet as a linear supply, while a cheap generic unit can make your receiver nearly unusable.
How to Actually Decide
- Home base station with a fixed location and no weight concerns: a linear supply is the safer bet if RF noise is a priority, and it usually is.
- Portable or semi-portable setups where weight actually matters: a quality switching supply from a radio-specific manufacturer is worth the tradeoff, especially since many are specifically engineered and marketed for RF-quiet operation.
- Tight budget: a well-reviewed switching supply from a company with a track record in the ham radio market beats a generic linear supply of unknown quality every time.
- Already dealing with mystery HF noise: if you are running a switching supply and hearing unexplained hash across bands, testing with the supply unplugged (running briefly on battery) is the fastest way to confirm or rule it out as the source.
What I Actually Run
My Astron RS-50M linear supply has been rock solid and completely silent from an RF standpoint, and that reliability is a big part of why I keep recommending linear supplies for a fixed home station where weight is not a concern. If I were building a lighter go-kit or a setup where portability mattered more, I would look at a quality switching supply specifically marketed to the ham radio community rather than a generic bench supply, since the radio-specific units tend to have noise suppression built in from the start.