Best Ham Radio Power Supplies: How Many Amps Do You Need? (2026)
For one 100 W radio, get the Samlex SEC-1235M. Choose Astron for fanless linear power, or Powerwerx for compact Powerpole convenience.
Quick picks
Samlex SEC-1235M
A communications-focused 13.8 V / 30 A switching supply with meters, useful protection and enough capacity for typical 100 W-class transceivers.
- 13.8 V / 30 A manufacturer output rating with front volt and amp meters
- RFI filtering plus overload, short, thermal and over-voltage protection
- Limitation: AC input is not automatic universal input; changing between 120 V and 230 V requires the specified internal setting
Astron RS-35M-AP
Choose this when eliminating switch-mode conversion and fan noise matters more than weight or efficiency.
- 25 A continuous / 35 A ICS with less than 5 mV published ripple
- Fanless linear design with meters and Anderson Powerpole connections
- Limitation: weighs about 27 lb — almost nine times as much as the compact switching supplies here
Powerwerx SS-30DV
The cleanest choice when you want a small desktop supply with two Powerpole outputs ready on the front panel.
- 25 A continuous / 30 A surge at a fixed 14.1 V output
- Two front Powerpole outputs plus rear binding posts in a roughly 3 lb chassis
- Limitation: no built-in volt/amp meters, and 25 A continuous gives little expansion room around a 21–23 A HF transmitter
Compare the three power-supply paths
Swipe → to see the full comparison
| Supply | Design | Current rating | Meters | Front DC access | Best for | Check |
|---|---|---|---|---|---|---|
| Samlex SEC-1235M | Switching | 30 A output rating | Volt + amp |
Metered front panel DC output terminals |
One 100 W-class radio | Current price → |
| Astron RS-35M-AP | Linear |
25 A continuous 35 A ICS |
Volt + amp | Powerpoles | Fanless / noise-sensitive shack | Current price → |
| Powerwerx SS-30DV | Switching |
25 A continuous 30 A surge |
No |
2 × Powerpole + rear binding posts |
Compact / quick-connect station | Current price → |
Do not size a ham-radio power supply by the number on the front
The radio’s manual gives you the load. The power-supply specification tells you whether the supply can support that load continuously.
Those two numbers — not the marketing name — belong in the comparison.
A current 100 W radio illustrates the scale. The Icom IC-7300MK2 specifies 21 A while transmitting at its maximum rated power. A supply capable of exactly 21 A would technically match that number but would leave no useful capacity for tolerances, accessories or future changes.
That is why I prefer meaningful headroom instead of buying the smallest supply whose specification just reaches the radio’s maximum.
Power-supply sizing helper
This is a planning aid, not a manufacturer requirement. It adds user-selectable headroom to the loads you expect to operate simultaneously. Always follow the radio and supply manuals.
21 A radio + 2 A accessories with 20% planning headroom = about 27.6 A.
The power-supply choices in detail
1. Samlex SEC-1235M
The SEC-1235M is my default recommendation because it is designed specifically around communications equipment rather than being a generic adjustable laboratory supply that happens to reach 13.8 volts.
Samlex specifies a regulated 13.8 V DC output at 30 A and explicitly describes the supply as intended for land-mobile-radio and communications applications. The front panel gives you both current and voltage meters, which is useful when you are building a station and want to see what the connected radio is actually doing under receive and transmit load.
More importantly for HF, Samlex says the design is highly filtered to suppress RFI and complies with FCC Part 15(B) Class B. It also includes overload, short-circuit, over-temperature and over-voltage protection.
All of that fits into a 3.4 lb enclosure. That weight difference is why good modern switchers have become so attractive for ordinary 100 W stations: compare it with 27 lb for the Astron linear supply below.
The main inconvenience is AC input. The SEC-1235M can be configured for 120 or 230 V operation, but the change requires the manufacturer’s specified internal jumper setting. If you need automatic worldwide 100–240 V input, look instead at Samlex’s newer SEC-P series.
Best for: a single 100 W HF/6 m transceiver or a substantial VHF/UHF base station where meters and useful current headroom matter.
Skip it if: fanless linear operation is the priority or you regularly travel between different mains-voltage regions and want automatic universal input.
2. Astron RS-35M-AP
A linear power supply solves a different problem. It is not automatically “better power,” but it avoids using the high-frequency switch-mode conversion stage that can become an RFI source in a poorly designed switching supply.
Astron specifies the RS-35M-AP at 25 A continuous with a larger 35 A ICS rating, 13.8 V DC output and less than 5 mV peak-to-peak ripple. The M version adds backlit voltage/current meters, while the AP version adds Anderson Powerpole connections.
It also runs without a cooling fan. That is useful in a quiet operating room where fan noise from a supply sitting next to the receiver would be annoying.
The price you pay is physical rather than hidden: the RS-35M-AP weighs about 27 lb and Astron specifies roughly 77% efficiency for this linear family. It is something you place in a permanent shack, not something you casually throw into a field bag.
Also notice the current specification: RS-35 does not mean 35 A continuous. The continuous figure is 25 A. That will run many 100 W-class radios whose manufacturer specifies around 20–23 A, but there is much less spare capacity than the model number can make a beginner assume.
Best for: a permanent HF shack where fanless operation and avoiding switch-mode conversion are worth substantial extra weight.
Skip it if: portability, efficiency or plenty of current headroom above a 23 A-class transmitter matters more.
3. Powerwerx SS-30DV
The SS-30DV makes sense when the station is already standardized around Anderson Powerpole connectors or you simply want a very small supply that can sit unobtrusively behind the radio.
Powerwerx specifies 25 A continuous and a 30 A surge capability for up to five minutes. Output is fixed at 14.1 V DC. Two Powerpole pairs are mounted directly on the front, while the rear binding posts accept banana plugs, ring terminals or bare/compression connections.
The whole enclosure is only around 6.1 × 5 × 2.5 inches and weighs about 3 lb. It includes over-current and thermal protection and uses a temperature-controlled cooling fan rather than running the fan continuously at maximum speed.
Powerwerx also publishes FCC Part 15 Class B and other EMC compliance for the unit. That is the kind of documentation I want to see before placing a switching supply immediately beside an HF receiver.
The limitation is again hidden in the model name: although it is called the SS-30DV, its normal continuous rating is 25 A. For a radio that can draw 21–23 A at full transmit power, it works close enough to its continuous ceiling that I would not also build a large accessory distribution system around the same supply.
Best for: a compact radio bench, Powerpole-based station, VHF/UHF mobile used at home, or a single transceiver whose current requirement leaves suitable margin.
Skip it if: you want built-in meters or intend to run several significant loads from one supply.
Need more than 30 A? Buy real continuous capacity.
If one supply will power multiple transceivers, a radio plus a significant accessory bus, or another setup whose actual simultaneous load goes beyond the supplies above, step up by the continuous-duty rating.
For example, Astron’s current SS-50M-AP switching model is specified at 40 A continuous / 50 A ICS. It also includes built-in Class B EMI filtering, over-voltage, over-current and thermal protection.
That is a much more useful distinction than replacing a “30 A” supply with a “35 A” product that still turns out to deliver only 25 A continuously.
Before sizing for multiple radios, calculate what can genuinely operate at the same time. Two connected radios do not necessarily require two transmitter peak currents if station procedure or interlocking means only one ever transmits — but accessories and receiving radios still consume power.
See Astron’s Current Continuous Ratings →Linear vs switching power supplies: which is better for ham radio?
Switching supply
A switch-mode supply converts power at a much higher switching frequency, allowing a much smaller and lighter transformer and chassis.
Advantages: light weight, compact size, generally higher efficiency and substantial current from a small enclosure.
Risk: poor switch-mode design or filtering can create RF interference. Buy communications-grade equipment with documented filtering rather than a generic bargain supply.
Linear supply
A traditional linear supply uses a large low-frequency transformer and linear regulation instead of high-frequency switching conversion.
Advantages: electrically simple, very low published ripple in quality units, and large fanless designs are available.
Tradeoff: much heavier and generally less efficient. The 27 lb Astron here is a perfect example.
My rule: I would not reject a properly filtered communications-grade switching supply merely because it switches. I would choose linear when the extra size and weight are acceptable and removing one possible local switch-mode noise source is valuable.
How to choose a ham radio power supply
1. Read the radio’s maximum current specification first
Do not start by deciding whether you want a 20 A, 30 A or 35 A supply. Start with the transceiver manual.
Look for the maximum current consumption at the required DC voltage. A modern 100 W HF radio commonly lands around the low-20-amp range; the current IC-7300MK2, for example, specifies 21 A during transmit.
Your exact radio’s number is the one that matters.
2. Size against continuous output — not the biggest printed number
This is the most common purchasing mistake in the category. Power supplies often advertise an intermittent, surge, peak or other short-term number more prominently than their continuous capability.
The Powerwerx SS-30DV is a useful example: 30 A appears in the name, but Powerwerx specifies 25 A continuous and 30 A surge.
Astron’s RS-35M-AP similarly specifies 25 A continuous and a larger 35 A ICS rating.
3. Leave useful headroom
I would not deliberately buy a supply whose continuous limit is exactly the radio’s maximum published current.
That leaves nowhere for additional receivers, control electronics, lighting or DC distribution — and it requires the supply to live at its ceiling whenever the transmitter reaches maximum demand.
There is no universal “20% law.” The calculator above uses headroom as a planning tool so you can see the effect. Follow the equipment manufacturers’ ratings first.
4. Match the voltage the radio actually specifies
Many mobile and HF amateur transceivers are designed around approximately 13.8 V DC, but allowed voltage ranges differ by radio.
Do not turn an adjustable bench supply up simply because a higher voltage appears to produce slightly more RF output. Stay inside the manufacturer’s DC-input specification.
Likewise, check polarity before connecting equipment. Reversing a high-current DC supply can damage electronics very quickly.
5. Keep the radio’s specified DC fuses
The supply’s own over-current protection protects the supply and overall circuit. It does not mean the radio’s manufacturer-specified inline fuses should be removed.
Use the supplied DC cable and fuse values unless the radio manufacturer instructs otherwise. If you add a fused DC distribution system, size each branch for the equipment and wiring connected to that branch.
6. Heavy current needs sensible DC wiring
Twenty or thirty amps is enough current for poor connectors and undersized wire to create meaningful voltage drop and heat.
Keep high-current DC leads reasonably short, use properly sized wire and connectors, and make mechanically secure connections. Do not route a 100 W HF station through a tiny accessory lead intended for a low-current gadget.
7. If you choose a switcher, test it across the HF bands
A properly designed switching supply can work very well in a ham shack. A badly filtered one can put repeating carriers, combs or broadband noise across the receiver.
With the antenna disconnected or terminated appropriately, listen to the receiver while turning suspect equipment on and off. If a new pattern appears when the supply is energized, troubleshoot before assuming weak-band conditions are to blame.
ARRL’s RFI resources are useful when tracking down a noisy station.
8. Fan noise is different from RF noise
A supply can be electrically quiet while its cooling fan is acoustically annoying during long receive sessions.
The Powerwerx uses a temperature-controlled fan. The Astron linear model recommended here is fanless. If the supply will sit two feet from your operating chair, this small ergonomic detail can matter every day.
9. Meters are useful, but they do not replace correct sizing
A built-in ammeter is convenient for seeing the station load under transmit and a voltmeter can reveal unexpected voltage sag.
But meters do not give an undersized supply more current capacity. Choose the correct electrical rating first; treat the display as a useful diagnostic feature afterward.
10. Powerpole connectors are convenient — not mandatory
Powerpoles make it easy to move radios between a shack, vehicle, battery box and portable setup when the rest of your equipment uses the same connector system.
That is why the Powerwerx and Astron AP models are convenient choices, but a secure ring-terminal or binding-post connection can be equally valid when installed correctly.
Never defeat the AC safety ground to cure radio noise or hum
A three-wire mains safety ground exists to protect you if an internal fault places hazardous voltage on the equipment chassis.
Do not use a cheater plug or remove the protective-earth connection as an RFI or ground-loop “fix.” Correct the station’s bonding, audio, RF or equipment problem instead.
Our grounding and lightning guide separates AC safety grounding, RF bonding and lightning protection so they are not confused with one another.
See these supplies in a complete first ham station
Our 2026 “Ham Radio Setup Under $500” video includes both the TekPower TP30SWII budget supply and the Powerwerx SS-30DV while showing where the supply fits into a complete VHF/UHF base station.
Important: that video is a complete-station guide, not a dedicated power-supply test. A 100 W HF transceiver can require more DC current than the VHF/UHF radio used there, so size your supply from your own radio’s manual rather than copying the setup blindly.
What to avoid
Do not buy a power supply rated exactly at your radio’s maximum draw.
I would also avoid choosing by model number rather than continuous rating, using a cheap generic switcher with no meaningful EMC/RFI documentation beside an HF receiver, removing inline radio fuses, or lifting the mains safety ground to make a noise problem disappear.
And do not buy 50 or 70 amps merely because “more is safer.” Size for the station you can realistically operate simultaneously and put the remaining budget toward the antenna, coax or test equipment that actually improves the station.
Where the power supply fits into your station
HF base station
Match the radio, DC supply, antenna and daily operating setup as one permanent station.
HF base station guide →Best HF radios
Check the exact current requirement of the transceiver before deciding how much supply you need.
Best HF radios →Budget HF radios
Lower-power HF radios can reduce both power-supply and portable battery requirements.
Budget HF radios →Mobile radio at home
A 25–55 W VHF/UHF mobile makes an excellent base radio when paired with the right AC-to-DC supply.
Best mobile ham radios →First HF antenna
Do not consume the whole station budget on the transceiver and power supply before planning the antenna.
Choose your first HF antenna →Coax & connectors
The DC side gets the radio powered; the feedline determines how much RF reaches the antenna.
Coax and connector guide →Grounding & lightning
Learn the difference between protective earth, station bonding, RF-current control and lightning protection.
Grounding & lightning protection →Portable operating
Away from mains power, the decision changes from an AC supply to batteries, charging and field energy use.
Portable ham radio gear →Accessories & DC distribution
Add distribution, adapters and other station accessories after the main current requirement is known.
Ham radio accessories →Ham radio power supply FAQ
How many amps do I need for a 100 watt ham radio?
Check the exact radio manual. Many modern 100 W HF radios draw somewhere in the low-20-amp range at maximum transmit power; for example, the IC-7300MK2 specifies 21 A.
I prefer a supply with useful capacity above the radio’s maximum rather than buying one whose continuous rating exactly equals the radio’s specified draw.
Is a 30 amp power supply enough for a 100 watt HF radio?
Usually when it is genuinely rated to provide the required current, but check what “30 amp” means for that specific supply. Some products advertise 30 A as surge output while their continuous rating is 25 A.
Is a linear power supply better for ham radio?
Not automatically. A good linear supply avoids switch-mode conversion and can have very low ripple, but it is much heavier and less efficient. A properly filtered communications-grade switching supply can also be an excellent shack supply.
Do switching power supplies cause HF interference?
Poorly designed or faulty switch-mode supplies can generate RFI. That is why I prefer products designed for communications use with documented filtering or EMC compliance rather than generic bargain supplies.
Switching technology itself does not guarantee that a supply will be noisy in your station.
Can I use a 50 amp power supply with a radio that only needs 20 amps?
Yes, provided the voltage and other specifications are correct. The radio draws the current it requires; the supply’s larger current capacity does not force 50 A through the radio.
You still need the correct radio-side fusing and wiring.
Can I power two ham radios from one supply?
Yes when the supply and DC distribution can safely support the maximum simultaneous load. Add the loads that can actually occur at the same time and include the connected accessories rather than simply counting radios.
Should I run my ham radio at 12 volts or 13.8 volts?
Use the voltage range specified by the radio manufacturer. Many mobile and HF amateur radios are specified around 13.8 V DC, but allowed tolerances vary by model.
Do not increase the voltage outside the specification in an attempt to get more transmitter power.
Do I need a metered power supply?
No. The radio can operate perfectly well from an appropriately regulated, protected supply with no front display. Meters are useful for seeing current draw and voltage sag, but they are a convenience rather than the reason a supply is electrically suitable.
Useful station-power resources
- ARRL — Your First Station — overview of station power supplies and switching-supply operation.
- ARRL — Radio Frequency Interference — useful if a supply or other household device appears to be raising your receiver noise floor.
- ARRL — Grounding — distinguishes AC electrical safety grounding from other station grounding requirements.
- Samlex SEC-1235M Specifications
- Astron Linear Supply Ratings
- Powerwerx SS-30DV Specifications
Licence and electrical-safety note: You do not need an amateur-radio licence to own or power radio equipment. Transmitting requires the appropriate licence and operation within your privileges. AC mains power can cause serious injury or death. Do not open or modify mains-powered power supplies unless you are qualified to do so, and never defeat the protective-earth connection. Follow the radio and power-supply manufacturers’ wiring, fuse, ventilation and voltage instructions. Wholly Outdoor is not affiliated with the FCC, NCVEC, ARRL, Samlex, Astron or Powerwerx.