Ham Radio: Workbench-3 Power Supplies

In this episode of The Workbench, George @KJ6VU and Jeremy @KF7IJZ take a look at power supplies for working on radios and electronic projects.

They breakdown the different types of power supplies, what to look for and make some shopping suggestions.

Segment 1 – News and Updates

HARA Arena closes.  Dayton Hamvention looking for a new venue.

Welcome our new sponsor – MCM Electronics and use the promo code RADIO5 to get 5% off your next order.


Check out our listener, Tim, KE4KE’s nice blog site with lots of great pictures and articles on portable operating at www.ke4ke.com

Our listener, Vance N3VEM, is hitting the road to do a NAPOTA-Thon – 12 national park activations in a 24 hour period.  Great blog site:  Projects and musings about ham radio from a new operator at http://www.n3vem.com

Our friend John, VE3IPS, makes a great video review showing how he sets up his PackTenna Mini antenna.   https://www.youtube.com/watch?v=z4RONXiPnkE&feature=share

What’s on George’s bench?
Shipped off the repeater and control system to Cale.  It’s a pair of Motorola CDM1550 radios and a Sierra Radio Systems repeater controller www.sierraradio.net

Sneak preview announcement … The first HamRadio 360 Workbench build project will be an antenna analyzer.  The design was created by Beric, K6BEZ.  You can see Beric’s prototype pictures and article on the project here…


The official build project is redesigned and updated on a single 3”x4” PCB.  You can build the whole thing yourself from your own junkbox of parts or you can get a full or partial kit.  The details are still being worked out.  Stay tuned for more.

What’s on Jeremy’s bench?
Battery Testing – comparing AGM, A123, and Bioenno – https://www.bioennopower.com/collections/12v-series-lifepo4-batteries/products/12v-8ah-lfp-battery-abs-sealed-black-case?variant=1014198656

Raspberry Pi Clock – from N0BEL – http://n0bel.net/v1/index.php/projects/raspberry-pi-clock

Repair Tytera MD-380 charging cradle



2 Categories

  • “Ham” 13.8 volt radio power supply
  • Bench / Lab power supplies

Ham “High Current” power supply considerations and tradeoffs

Linear vs Switching?

Variable Voltage vs Fixed Voltage?

Meters vs no meters?

What do you add as you go up in price?

  • Precision
  • Linearity
  • Low Noise/Low Ripple
  • More current/power
  • Computer connectivity/programmability

Linear 12V High Current Power Supply: Astron RS-35A – $180 – http://www.hamradio.com/detail.cfm?pid=H0-004434

Switching 12V with Analog Meters: Samlex 1235M – $130 – http://www.mcmelectronics.com/product/SAMLEX-AMERICA-SEC-1235M-/72-12820

Switching Variable Voltage with Meters: Powerwerx SPS-30DM – $160 – http://www.hamradio.com/detail.cfm?pid=H0-011684

Switching 12V: Powerwerx SPS 30DV – $110 – http://www.hamradio.com/detail.cfm?pid=H0-010662

Switching 12V Variable Voltage: Alinco DM-330MVT – $160 – http://www.hamradio.com/detail.cfm?pid=H0-003728


Key specs to look for

  • 0-20v or more
    • Single ended 0-20v – voltage reference to ground
    • Maybe Dual ended +/- 15 volts
  • Low ripple (<1mv p/p) – what is ripple?
  • EEVBlog Ripple and Noise https://www.youtube.com/watch?v=Edel3eduRj4
  • 2-5 amps
  • Meters for Volts and Current (digital or analog)
  • Current limiting adjustment
  • Resettable output breaker
  • Short circuit protection

What do you add as you go up in price?

  • Precision
  • Low Noise/Low Ripple
  • More current/power
  • Computer connectivity/programmability

EEVBlog – earth ground vs ground referenced circuit:  https://www.youtube.com/watch?v=xaELqAo4kkQ

George’s old favorite:  used  B+K Dynascan 1601  0-30v 0-2A resettable breaker  ($60-$100)

Product Recommendations

Tenma 72-8345A 1-36V 3A Power Supply – $150 – http://www.mcmelectronics.com/product/TENMA-72-8345A-/72-8345A

Tenma 72-8350 1-20V 5A Power Supply – $160 – http://www.mcmelectronics.com/product/TENMA-72-8350A-/72-8350

Tenma 72-9465 1-36V 5A USB Controllable – $200 – http://www.mcmelectronics.com/product/TENMA-72-9465-/72-9465

GW Instek GPS-1850D – $200 – http://www.mcmelectronics.com/product/GW-INSTEK-GPS-1850D-/72-12100

Common mode choke reference:  http://www.karinya.net/g3txq/chokes/

One comment

  1. I worked in the power supply industry for almost 30 years and have a lot of experience with linear and switchmode supplies. In general the linear supplies are lower noise and more robust, the switchmode units can have hash on the output and can fail in spectacular fashion but they do save on weight and cost for low voltage high current units.

    If you need an adjustable power supply for circuit development you can get lab grade linear units for very little cash on ebay. I picked up a PXI three output + / – 0-32v and a 0-7v 7a power supply for little more than the cost of shipping. This was built in the 60’s and is far better built than anything your going to buy new, I replaced a cap and a switch and it works great. The year before i picked up a 0-50v 2.5a unit that looks like it went through a war but works fine, both units are fully metered for voltage and current.

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