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Mean Well OWA-120E-20, power supply for 50W amp #pa

Ben
 

Hi all,

Just want to let you know my experience with this Mean Well OWA-120E-20 PSU. The output is 20V, 6A. The PSU has protections for short circuit, overload, over voltage and over temperature.

First I tried a cheap Korad KD3005D linear power supply, but that one was humming/buzzing along with my morse code. This one is completely silent.

I connected the QCX via a USB-C PD trigger @12V, the output was just a bit more than 3 Watt. Connected the QCX PA with this PSU (see attached photo). I was listening to a close by on-line SDR receiver, and with the PA the signal went up by 10dB. When I have an SWR meter, I will measure it. At the moment i only have a QRP SWR meter ^_^


73, Ben
PA2ST

Ben Bangerter, K0IKR
 

On Mon, Jul 13, 2020 at 02:14 PM, Ben wrote:
— a USB-C PD trigger @12V —
What on earth is that?

73, Ben  K0IKR

Dirk Räder
 

I suppose that's a step-up converter from 5V USB-C Power Delivery, which supplies around 100W. With a decent converter, that's more than enough power for QRP.

73, Dirk DB6EDR

Am Di., 14. Juli 2020 um 14:30 Uhr schrieb Ben Bangerter, K0IKR via groups.io <bwbangerter=yahoo.com@groups.io>:

On Mon, Jul 13, 2020 at 02:14 PM, Ben wrote:
— a USB-C PD trigger @12V —
What on earth is that?

73, Ben  K0IKR



--
Dirk Räder DB6EDR
Morissestr. 7
26180 Rastede
M: +49-176-60835036

Shirley Dulcey KE1L
 

A USB-PD trigger is not actually a power supply. It's a small board that you plug into a USB-C power source (AC adapter or battery power bank) that pretends to be a device that is requesting power delivery at the specified voltage and current. You then plug your non-USB device (like a radio) into it to get power. USB-PD power adapters are becoming more common, so I expect them to become a popular way to power low power ham radio equipment; the spec is limited to 100W so 50W transmitters are probably about the limit, and at that power level you're going to need an efficient transmitter. (Not your typical mainstream 100W transceiver, which uses 250W or so from the power supply to produce its 100W output and would probably be even less efficient at 50W out.)

USB Power Delivery version 1 offered three fixed voltages: 5V, 12V, and 20V. Version 2 offered four: 5V, 9V, 15V, and 20V. (12V was dropped for some reason, though a device designed for USB-PD 2.0 might also have backward compatibility with USB-PD 1.0 and offer that voltage.) The current version 3 allows the device that requests power to ask for any voltage between 5V and 20V in 20mV steps. Not all power sources implement that, and a source can reply that it is incapable of supplying the voltage and current that have been requested. Small adapters for phones and tablets, for example, usually don't go all the way up to 20V.

If you want to use a USB-C power source to run your radio, you'll need to test it to determine whether it can supply your power demands, in addition to the usual checks for RF noise and voltage regulation under big swings in load such as keying a transmitter. Most uses of those adapters don't have such large rapid swings in power draw so they may not handle them gracefully.

On Tue, Jul 14, 2020 at 9:02 AM Dirk Räder <dirk@...> wrote:
I suppose that's a step-up converter from 5V USB-C Power Delivery, which supplies around 100W. With a decent converter, that's more than enough power for QRP.

73, Dirk DB6EDR

Am Di., 14. Juli 2020 um 14:30 Uhr schrieb Ben Bangerter, K0IKR via groups.io <bwbangerter=yahoo.com@groups.io>:
On Mon, Jul 13, 2020 at 02:14 PM, Ben wrote:
— a USB-C PD trigger @12V —
What on earth is that?

73, Ben  K0IKR



--
Dirk Räder DB6EDR
Morissestr. 7
26180 Rastede
M: +49-176-60835036

Armin, DJ2AG
 

USB-C Power supplies or powerbanks can deliver up to 20V. Devices negotiate with the power supply what max. voltage they can handle. If you want to use these power supplies with other devices not capable of communicating their power needs you can use  a USB-C PD trigger module, which is plugged between power supply and e.g. a QCX.

But I don’t see how such a module will be of use with the Meanwell PS. Maybe Ben uses a Powerbank for the QCX.

Armin, DJ2AG

Ben
 

I was using a RAVPower PD Pioneer 20000mAh powerbank to power the QCX @ 12V. This powerbank can deliver 5, 9, 12, 15 and 20V at 3A. Really neat. I have made a cable with a PD-trigger for 12v and one for 15v, so I can swap them easily. I now also have an Aukey PA-D4 charger that supports the same range of voltages also at 3A. They can even power a KX2 at 12W output with no problem.

I you want to read more about USB-C PD, i recommend this blog from Gwen N3GP: https://www.ng3p.com/2020/05/a-different-power-source-for-field-ham.html

The Meanwell PS is for the QCX 50W PA. Yesterday I made 3 contacts on 40mtr with it (G, EA and OK). The 50W PA was warm, but not too hot. The Meanwell PSU was feeling like room temperature. It was not dropping out, not getting hot and not buzzing along ;-)