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Linear Or Switching Power Supply?

Discussion in 'General Technical Questions and Answers' started by KT4JX, Mar 29, 2008.

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  1. KT4JX

    KT4JX Ham Member QRZ Page

    That's good advice, and no, I don't truly need 35 amps. I was just going that route to give myself a little breathing room. It's good to hear that it doesn't use a fan. That's one less thing to worry about.

    It looks like I'm gonna go with the RS-35M based on everyone's advise. I plan on using it at home so the extra weight is no problem, and really, at 27 pounds, it doesn't seem that bad. The low noise is the main thing, because even if many switchers are designed for low noise in the ham bands, I also wanna use it for SWL'ing, CB, and AM broadcast.

    HRO should be hearing from me shortly. :D
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    One advantage to switch mode power supplies besides the lower weight is that they can normally operate over a very wide range of input voltages (AC line), like from 90 to 260Vac without even needing a line voltage switch. So, it's much easier to make a "plug & play" switching power supply that will work anywhere in the world without having to make variations of the supply.

    Linear power supplies at 12-14 Vdc output probably won't be made by anybody in another ten or fifteen years. However the Astrons are good, and my RS-70M (70A version) has been powering a lot of my "shack" for 20 years now. I never turn it off.

  3. N9XR

    N9XR Ham Member QRZ Page

    I have had good luck with my Austron power supply. This one is a linear design.
  4. N2RJ

    N2RJ Ham Member QRZ Page

    Same with mine, and it has been subjected to generator and 3rd world power, and never skipped a beat.
  5. N2RJ

    N2RJ Ham Member QRZ Page

    Which model did you have?
  6. N9XR

    N9XR Ham Member QRZ Page

    I have the model JTPS28M and have attached that thing to the spectrum analyzer and it looks clean to me. I looked at the ham bands and there was no measurable noise or birdies at -110 dBm.
  7. N6YG

    N6YG Ham Member QRZ Page

    When you tested it was it under full peak load or was it just loafing along. I'm assuming that it was under idle conditions, because if you tested it under load I'm sure you would have said so. Anyhow I'm sure the newer models have improved. The problem is in the base technology, without extensive well designed filtering can and does cause problems.. Unfortunately most hams wouldn't recognize it when they heard it or just don't know how the heck to test for it. For the most part I'm sure that for the average ham with a high noise floor they would never notice any interference from their power supply. But ham's who have gone out of their way to build efficient receiving station or hams living in areas with low noise floor would more then likely notice it.

    Maybe I'll pick one up for my son. He is using a IC-725 with the matching Icom PS-55 and AT-150 antenna tuner. He is talking about selling the whole kit so he can buy an FT-847
  8. N9XR

    N9XR Ham Member QRZ Page

    No. Not at peak load. I was dumping about an amp throgh the radio on receive. Receive is where I am most concerned anyway. I used a high impedance FET scope probe on the PS output.

    What will a few hundred micro volts do to me on transmit?
  9. N9XR

    N9XR Ham Member QRZ Page

    I have an Austron power supply I need to work on and get it going again. It is much more robust anyway even if it is a gut buster.
  10. AC0FP

    AC0FP Ham Member QRZ Page

    I purchased a Samlex brand switcher when I bought my IC-718. I had reservations about getting a switching supply for HF use but the guy at the local amateur radio store assured me that they had tested the SEC1223 for RFI and found none, nor had they ever had a complaint from a customer. I of course checked it out for myself and found no noise difference between it and a linear (Astron) supply.


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