Just for the record... After Jim pointed out the noise in my system the power supply was making, I immediately ordered a linear power supply. Noise is now GONE! Thanks Jim for another great tip. The next cup of coffee is on me. 73, Cal AI6MC
Thank you, Jim. Some of those pulse modulated or switching power supplies are so noisy that even local AM and FM stations are difficult to listen to. We are in a remote area, but still these PWMPS are in major violation of FCC regs! N0QFT
Thanks Jim for the explanation. A few years ago, I ordered a small receiver kit from a well known and respected ham radio US Manufacturer that was making me crazy as it was so noisy; all the tests went well so I couldn't find the problem till I tested with a 12 Volt UPS battery. The receiver went quiet and was working nicely. The culprit was the wall transformer it came with. I couldn't believe that the unit came with a cheap weightless switching power supply!!! So went to a local electronics parts store an bought a small multi voltage wall little transformer but the type that still comes with filtering and real transformer. No more problems. On the other side, now that I have learned more, bought a SEC-1223 from Samlex which is a switching power supply, for my portable setup with a Yaesu FT-857 and that thing had to be professionally heavily modified by adding filtering everywhere inside. It works fine but not an easy job. Better stay with the old trusty type of heavy power supplies for your station at home.
Good video Jim. As an old EE i designed supplies many years ago, nothing matches or outlasts a good power supply with a strong transformer, full-wave bridge rectifier, filtering system etc. They last forever and produce little noise.
I have the same supply in my home shack. I picked it up cheap but in near new condition. My thinking was to do with the power efficiency of the switching supply over my old Watson 30 amp linear. I ended up using it for about ten minutes before going back to my old Watson. Makes a nice high power bench supply for testing purposes but I agree with you with regards to day to day Ham usage. Linear supplies will always be the first choice. Karl, M0KRL.
That's good to know. I keep reading that the modern good quality type of switching power supplies are just as quiet as the transformer types, but now I'm suspecting they're probably referring to use with VHF & UHF bands, not HF bands. I've had mobile HF, VHF, and UHF radios for a few years now, and I've been thinking of putting together a portable base station with the purchase of a ICOM 7300, and a magnetic loop antenna.
Oldhogleg It is possible to make a quiet switching power supply, but it means designing added filtering to both the AC input side as well as the DC output side in order to to remove the unwanted emissions at LF, MF and HF frequencies. I am also a big fan of linear supplies for fixed base stations and also love that they are electrically easy to understand and repair for anyone with even basic electronics knowledge (unlike switching supplies). However, when I converted my home station to operate with an integral battery backup (*everything* station related runs from the battery rails) that meant I needed to make use of DC-DC converters (essentially the same as switching power supplies) to get the voltages I need to operate radios, lighting, computer, and monitors all from flooded lead acid batteries whose rail voltages could range anywhere between 10.5-14.4VDC, or a bit less at the equipment due to voltage drop along the way, depending upon their state of charge. Some of the DC-DC Converters were fine as-is, barely emitting anything at a distance of just 6" over the span of 500KHz to 1GHz while others were very strong emitters straight out of the box and required heavy filtering to remove the noise, reducing such to below background levels. At this point I can honestly say the biggest emitters at my station are the two 27" monitors due largely to the PWM modulation of the backlights, fortunately my antennas are well away from station at home and perpendicular the the monitors so such is not a concern. But it is possible to have a quiet switching supply, it just requires added engineering and attention to detail, which also drives up cost a bit. --KW4EK
The real problem is that linear power supplies these days are getting _really_ hard to come by. I searched for power supplies on one ham shop's website, and every single one of them was a switching supply.
years ago I got an older icom ps-30 which I believe is a switching supply. it has an Icom style HF DC power connection hardwired, so I used it with an iC-737 from that same era. Why would the big 3 radio manufacturers put their name of HF switching power supplies if they were so bad? I don't disagree that the linear transformer type are a safer bet, but there are so many switching supplies marketed for hams, this is surprising.
I have used switching wall packs with cctv cams in the past and has degraded the picture quality severely. I thought about purchasing an Alinco or Jetstream switcher very similar to the p.s. in your video, now i will think twice. Thanks for posting! KC5NGX
Thanks Jim a Little Heads Up Goes A Long Way ,Some Where The Word About These Power Supply's Was Most Likely Posted In One Of The You Tube Sites I Watch So I Was Never Out Side The Lope On Switching Power Supply's And Will Never Buy One ,Old School No Switches I Hope The New Hams Pay Close Attention To What You Have Put Into The Content Of This Vidoe. n2wjs Charlie.
Thanks Charlie. Some guys have written to say that their switching power supply does not generate noise. I have not seen that, but they may very well be correct. Maybe with enough filtering it can be clean. Nice to hear from you again Charlie. 73, Jim
As of Oct/15/2002 SMPS are made really well and are quite. Best ones are from Samlex SML-1235M or Powerwerx SPS-30DM or ASTRON SS-30M-AP are all quite supply's.
Good afternoon Jim. I'm just a RU-vid browser. I heard the term "ham radio" in regards to "prepping". The search led me to your video about calling CQ. In the video you gave us a demonstration about calling CQ and we're connected with a man outside of Dallas. I found the conversation incredibly interesting! Is there any way possible you could upload a few videos of radio conversations in their entirety? I hope you're feeling better! -thanks
This is really interesting as I just spent a couple days camping with my new SDR radio and a long wire. I was getting lots of These tones and did not know where they were coming from. Since my SDR radio is powered by the laptop, power supply for the laptop that is causing these tones and did not know where they were coming from. Since my SDR radio is powered by the laptop, power supply for the laptop that is causing these tones?
My PSU is a Watson 45 NF and is as clean as a whistle. I also have A Watson linear PSU that hates 6m, though its fine now I have decoupled the regulator chip
I have been told that noise can also be generated by anything and everything plugged into one of those power strips that are so popular. Can even those federally mandated smart meters do the same thing?
Noise! NOISE?!! I have -60dbm here caused by Virgin Media network problem and they are not happy to come out to fix the bloody thing. I'm ready with my parrot-beak cutters to force the issue. 18-months I've suffered this and have to have a shack out in the boonies to hear anything.
Gday Jim could you please help me find the raincoat tape ? I am keen to buy it for my new Hf installation. Thanks Jim for your time and help. 73z Richard vk2ual
Just interested to know what people think about the power supply that Icom sell with their transceivers (IC-7410 with a PS-126 switch-mode power supply) - Have they been well designed electonicly to minimise noise etc 73 - Leon
By the way, my noise is from 500:kHz through 50mHz.... Anyone beat that? Network engineers are not what they used to be. I'm going to stand over them with a bazooka and make sure they fix the job once and for all, otherwise.......
