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Ham/CB/other transmitter radios... linear vs switching PSU?

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    Ham/CB/other transmitter radios... linear vs switching PSU?

    Now I don't own any HF gear other than CB, but there still seems to be some arguments against switching PSUs.

    Do people still have a good reason to use a linear PSU?

    Or is it fully possible to clean up a switching PSU so that it won't interfere a radio?

    Now that it seems Yaesu even doles out switching PSUs, is this a sign to start getting rid of linear PSUs?

    #2
    Re: Ham/CB/other transmitter radios... linear vs switching PSU?

    switchers must be well filtered - cheap ones arent.
    and they need LOTS of output capacitance to keep them stable between RX that is probably only a couple of watts and TX which sure as hell isnt.

    Comment


      #3
      Re: Ham/CB/other transmitter radios... linear vs switching PSU?

      cheap smps always litter the hf spectrum with their wandering birdies.
      a surprise is that an xbox 360 supply does well for running 100w hf rigs.
      they dont like cap charging inrush so connect then power on.
      i have one at the shop running a kenwood ts50 over 3 years.
      even with their weight and poor efficiency i prefer an old linear astron.
      but if you need something to get on the air with an xbox 360 brick can be free from a dead game.
      the older ones are rated for up to 18a.

      Comment


        #4
        Re: Ham/CB/other transmitter radios... linear vs switching PSU?

        I was more wondering about people deathly afraid of using SMPS with HF - heard someone mentioned it recently. Yes it's worth experimenting/testing but definitely don't preclude it.

        Then there's also the VHF/UHF radios, which seem to be more tolerant of SMPS?

        Comment


          #5
          Re: Ham/CB/other transmitter radios... linear vs switching PSU?

          ^ I run my rigs on a pair of Dell Poweredge 2500 PSUs. Works well.
          Last edited by goontron; 07-20-2018, 09:38 AM.
          Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

          "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

          Excuse me while i do something dangerous


          You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

          Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

          Follow the white rabbit.

          Comment


            #6
            Re: Ham/CB/other transmitter radios... linear vs switching PSU?

            Currently I only have 70cm LMRS radios tuned to ham bands, and using SMPS just fine. Almost seems just getting enough watts is sufficient, I'm using a random 12V 40W SMPS PSU that I adjusted to 13.8V on one of my radios - can't seem to hear PSU noise.

            That PSU is being shared with the ancient 2m radio... which isn't being used, yet...

            My 35W LMRS radio makes the 40W SMPS die on transmit. Well, that figures, so much for radio efficiency

            Comment


              #7
              Re: Ham/CB/other transmitter radios... linear vs switching PSU?

              well most ps run at 30-80KHz so they are going to be more of a problem for people running in the sw area.

              Comment


                #8
                Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                A linear PSU is the quietest, great for DX and 6-8 digit multimeters.
                But your noise floor is always limited by other interference, usually the neighbor's cheap computer gear.

                Any SMPS that passed EMC regulatory like FCC part 15 or EN550xx will have decent filtering and low emissions, i.e. Meanwell 50W PSU.
                SMPS wall adapters are ungrounded and less room for filtering components, so not good for radios, I find.

                The cheap Ali or eBay PSU's that have never been tested or certified for EMC- they are a crap shoot.
                Some have the filter components just jumpered out. You can add a line filter and CM choke on the output though.
                The really cheap chinese PSU's I find unstable and make tons more EMC.

                Comment


                  #9
                  Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                  Here we go... I got an 175W Xbox PSU, time to up it to ~13.8V and use it to charge the backup battery and power the shack. Then I can stop using the little 40W switcher...

                  I wonder if I'll need to add any noise elimination hacks to it... hopefully not.

                  Comment


                    #10
                    Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                    keep it clean,
                    they contain a fan and pull air from one end to the other across a huge heatsink.

                    Comment


                      #11
                      Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                      oh weird, I thought it was passively cooled, strange... did not see any fanlike vents. Grr. Oh well.

                      Comment


                        #12
                        Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                        Oh this sucks. I have to trick the supervisor circuit too? This thing has OVP/UVP with an internal reference! Grr!!! I guess no battery charging with this...

                        Comment


                          #13
                          Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                          I have used switching PSU's on 100 watt radios in the past, and I have tried the Xbox 360 gig. I don't know while they do seem to work I just don't feel comfortable unless I am using a heavy linear supply of which I have no shortages of. Also I have float charged a bank of lead acid batteries in the past to power my radio equipment, I suppose if I had a real need to use smps then I might get around to feeling differently and I do have a couple of surplus corsair 1200 watt supplies.

                          That said I know several local radio amateurs who use 50 volt smps supplies for their high power solid state amplifier's either 400 watt or 1 kw amps and they seem to get away with it.

                          Comment


                            #14
                            Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                            It may be hard to find in specifications, but frequency jittering (helps reduce EMI) is a good feature to look for in a switching power supply for this application.
                            My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

                            Comment


                              #15
                              Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                              that's called "spread spectrum", pc motherboards usually use it too.

                              Comment


                                #16
                                Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                                Problem with a 12.0V power supply is that the voltage isn't high enough to charge...

                                I also have a half-made homemade linear using the parts I had on hand. I had it working well with one series pass transistor, alas I wanted to parallel two so it can safely pass 10A+ total. Just don't have enough of the right parts to implement foldback for two transistors.

                                Yes it was kind of scary shorting the output to test foldback, but it worked when it was just one pass transistor!

                                Comment


                                  #17
                                  Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                                  AHA! I think I found the parts that I need to change to adjust the voltage on the xbox PSU... though the %#&*!@$ stupid @*()$#@(% chip manufacturer of the #($(#@%*#^ supervisory chip did not *(#%$@% clearly specify the %*(%# specifications of the OVP input...GRRR... However it minimally won't cut out under 13.4V so I probably can get it to 13V without modifying the OVP, above that might get into the risky zone depending on how lucky I got with the chip.

                                  The other possibility is to remove the chip, but OCP is also handled by this circuit.
                                  Last edited by eccerr0r; 12-26-2018, 09:35 PM.

                                  Comment


                                    #18
                                    Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                                    SUCCESS! With some risk of the OVP failing... at least it worked for me luckily!

                                    I have: Microsoft XBox PSU Model HP-AW175EF3 (HiPro made in China)

                                    Noting that the resistors on the board are all glued and soldered, I figured the best way is to parallel a resistor.

                                    I paralleled a 36K resistor (it's what I had in my junk box...) to the existing R318 on the board. I got a resultant voltage of ...

                                    13.73 volts (unloaded)!

                                    Close enough! This should be excellent for a car battery eliminator. Now I need to have a connector on the output that's actually usable...

                                    I need to work on my SMT rework skills... or actually have some good flux or something.

                                    BTW: Yes, my noise floor in my house for 2m/70cm is pretty awful... all my computer gear it appears *sigh* In fact it seems when I have BCN loaded one of my monitors, it causes tremendous noise picked up on 70cm. It's kind of hilarious, I can hear it when I move a window off one display to the other...

                                    Tradeoffs...
                                    Attached Files
                                    Last edited by eccerr0r; 12-27-2018, 01:07 AM.

                                    Comment


                                      #19
                                      Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                                      XBox HP-AW175EF3
                                      Output: 13.73V DC
                                      Test device: car headlamp
                                      Amperes: 4.27A
                                      Watts: 58.63W
                                      Measured wattage at wall: 75W
                                      Efficiency: 78%
                                      PF: 0.69

                                      Standby power: below resolution of measurement
                                      Power on, no load: 6.5W
                                      Last edited by eccerr0r; 12-27-2018, 04:18 AM.

                                      Comment


                                        #20
                                        Re: Ham/CB/other transmitter radios... linear vs switching PSU?

                                        Originally posted by eccerr0r View Post
                                        XBox HP-AW175EF3
                                        Output: 13.73V DC
                                        Test device: car headlamp
                                        Amperes: 4.27A
                                        Watts: 58.63W
                                        Measured wattage at wall: 75W
                                        Efficiency: 78%
                                        PF: 0.69

                                        Standby power: below resolution of measurement
                                        Power on, no load: 6.5W
                                        Could you please post exactly what you changed to make work
                                        Reference number that are on the board

                                        Thanks
                                        9 PC LCD Monitor
                                        6 LCD Flat Screen TV
                                        30 Desk Top Switching Power Supply
                                        10 Battery Charger Switching Power Supply for Power Tool
                                        6 18v Lithium Battery Power Boards for Tool Battery Packs
                                        1 XBox 360 Switching Power Supply and M Board
                                        25 Servo Drives 220/460 3 Phase
                                        6 De-soldering Station Switching Power Supply 1 Power Supply
                                        1 Dell Mother Board
                                        15 Computer Power Supply
                                        1 HP Printer Supply & Control Board * lighting finished it *


                                        These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                        1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                        2 Hem Saw Computer Stack Board

                                        All of these had CAPs POOF
                                        All of the mosfet that are taken out by bad caps

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