See that faint line on the waterfall in the video? It's coming from this power supply. And when I turn a knob on the front, it moves. That's exactly what the Noise Offset control on the Radioddity PS30 is supposed to do, and it's the most interesting thing about this supply.
The PS30 is a compact switching power supply built specifically for radio use. Producing 13.8 volts is not the hard part. Any supply on the shelf can do that. The real question with a switching supply in a ham shack is whether it can do it without becoming a source of noise in your receiver.
So that's what I went looking for. I powered a radio from it the way I would any other supply, then got progressively pickier about how hard I looked for interference. Here's what I found, and what that Noise Offset knob is actually doing.
PS30 Overview: What You Get
The PS30 is rated for 20 amps continuous and 30 amps peak. That puts it right in the range for powering a typical 100 watt HF radio, and it's more than enough for mobile VHF/UHF rigs, a QRP radio, or a desk full of accessories.
There are two voltage modes. Fixed mode gives you a steady 13.8 volts, which is what most radios are designed to run on. Switch it to adjustable mode and you can vary the output from 8 to 15 volts. That's handy for gear that wants something other than 13.8, or for seeing how a radio behaves when the voltage sags like a battery would in the field.
- Front panel: two Anderson Powerpole compatible outputs, plus separate backlit meters for voltage and current, so you can watch your draw while you transmit.
- Rear panel: the heavier screw-type binding posts, the cooling fan, and the AC input.
- Noise Offset knob: the unusual one. More on that below.
- Protection: Radioddity lists short-circuit and overload protection.
It's a fairly straightforward power supply, but the layout makes sense for a radio desk. Powerpoles up front for the radios you plug and unplug, binding posts in the back for the permanent connections.
First Test: Powering the Xiegu G90
I started by connecting the PS30 to my Xiegu G90 and using it exactly as I would any other power supply. On receive, there was nothing unusual. The voltage stayed stable, the meters were easy to read, and the supply wasn't doing anything to draw attention to itself.
That's a good start, but it isn't a noise test. The PS30 is a switching supply, and switching supplies have a reputation for noise. Sometimes it's earned. A poorly filtered one can scatter birdies and broadband hash across your receiver, and then every weak signal you chase has to fight your own shack first.
So I went looking on purpose. I scanned around the bands, watched the waterfall, and turned the Noise Offset control from one end of its travel to the other, watching for anything that moved with it. I couldn't find anything obvious coming from the supply.
That was a good result, but I didn't want to stop there. The G90 has a relatively small display, and faint, narrow signals aren't always easy to pick out on it. If the PS30 was putting out anything, I wanted a better tool to find it.
Hunting for Birdies with the Hermes Lite
Next I moved over to the Hermes Lite SDR. The larger spectrum display made it much easier to inspect a wide section of the band at once and watch for anything that shifted when I adjusted the supply.
Making It Unrealistically Quiet
I also terminated the receiver input with a dummy load instead of an antenna. That removes normal signals and atmospheric noise from the picture, creating an unrealistically quiet environment where very faint interference becomes much easier to see. It's not how anyone operates. It's how you find things that would otherwise hide.
Finding the Line
Around 1.8 MHz, I finally found it: a very faint line on the display. On its own, a faint line could be anything. So I turned the Noise Offset knob.
Confirming the Source
When I rotated the control, the line moved. That confirmed two things at once. First, that faint birdie really was coming from the PS30. Second, the Noise Offset control is not a decorative knob. It does something you can see.
How the Noise Offset Control Works
This is the part that's easy to misunderstand from the name. The Noise Offset knob does not turn the noise level up or down. It's not a filter and it's not a noise blanker.
A switching supply works by switching its power circuitry on and off at a high rate. That switching frequency, and its harmonics, is where birdies come from. The Noise Offset control slightly changes that switching frequency. When the switching frequency moves, the interference the supply generates moves right along with it.
So in practice: if a birdie from the supply happened to land right on a frequency you wanted to use, you'd turn this knob and slide the birdie out of the way. A frequency that was unusable becomes usable again. That matters most on narrow modes, especially CW, where a steady carrier sitting on top of a weak signal is exactly the thing that ruins a contact.
The Noise Offset knob doesn't turn the noise down. It moves it out of the way, and it actually works.
So, Is the PS30 Quiet Enough for Ham Radio?
Here's the part that matters. Those birdies were faint. Very faint. To see one at all, I had to terminate the receiver input with a dummy load, use a large SDR display, and deliberately go searching for it. When I switched back to an antenna, they were down in the noise and not noticeable.
On the G90, in normal use, I couldn't find anything obvious at all. That's a good result, and the Noise Offset knob is there as a backup plan if your station ever puts a birdie somewhere inconvenient.
To keep it honest: this was a receive-side noise hunt on two receivers in my shack. Your results will depend on your radios, your antenna, and everything else plugged in nearby.
Radioddity PS30 Key Specs
Output Current
20 amps continuous and 30 amps peak, enough for a typical 100 watt HF transceiver.
Output Voltage
Fixed 13.8 volts DC, or adjustable from 8.0 to 15.0 volts DC. Radioddity rates output voltage regulation at less than 2 percent.
Noise
Ripple noise rated at less than 80 mV peak to peak at rated load, plus the adjustable Noise Offset knob for moving the switching frequency.
Connections and Meters
Anderson Powerpole compatible outputs on the front, screw-type binding posts on the back, and dual backlit meters for voltage and current.
Input and Protection
110V AC input, short-circuit and overload protection, and a 5 amp internal fuse per Radioddity's spec sheet.
Size and Weight
6.1 x 3.0 x 8.1 inches and approximately 3.3 pounds. The box includes the PS30 and a power cable.
Frequently Asked Questions
What is the Radioddity PS30?
It's a compact switching DC power supply made for radio use. It runs from 110V AC, gives you a fixed 13.8 volts or an adjustable 8 to 15 volts, and is rated at 20 amps continuous and 30 amps peak. It has dual voltage and current meters, Powerpole compatible outputs, binding posts, and a Noise Offset control. Radioddity lists it at around $120.
Can it power a 100 watt HF radio?
The 20 amp continuous and 30 amp peak rating puts it in the range for a typical 100 watt HF transceiver. Check your radio's manual for its maximum transmit current draw and make sure it fits the way you operate.
What does the Noise Offset knob do?
It doesn't turn the noise up or down. It slightly shifts the supply's switching frequency, and any birdie the supply produces moves with it. If one lands on a frequency you want, turn the knob and move it out of the way. In my test, a very faint birdie near 1.8 MHz moved when I turned it.
Is the PS30 noisy on HF?
Not in my testing. I found nothing obvious on the G90. Only with a Hermes Lite SDR, a dummy load on the input, and a big spectrum display did a very faint birdie show up near 1.8 MHz, and on an antenna it was down in the noise. Radioddity rates ripple at less than 80 mV peak to peak at rated load.
What connections does it have?
Two Powerpole compatible outputs and the voltage and current meters are on the front. The heavier binding posts are on the back, along with the cooling fan and the AC input.
Should I use fixed 13.8V or adjustable mode?
For most radios, fixed 13.8 volts is the simple, safe choice. Adjustable mode covers 8 to 15 volts for gear that needs something different or for testing at lower voltages. Always stay inside the range your equipment's manual specifies.
Conclusion: The Best Compliment for a Power Supply
A power supply is one of those pieces of equipment you only notice when it causes a problem. Noise in the receiver, voltage dropping under load, an annoying fan, something that keeps reminding you it's there. I went out of my way to make the PS30 cause a problem, and the best I could do was a very faint birdie that needed a dummy load and an SDR display to see, and that I could move with a knob anyway.
Add in the 20 amp continuous rating, the fixed and adjustable modes, Powerpoles up front, and meters you can actually read, and it's a sensible supply for a radio desk.
So far, the PS30 hasn't given me any reason to notice it. It just sits there and powers the radio. For a power supply, that's probably the best compliment I can give it.
Get the Radioddity PS30
A compact 20 amp continuous switching supply with fixed and adjustable output, Powerpole compatible connections, and a Noise Offset control for moving birdies out of your way.
Shop the Radioddity PS30 at Radioddity