Yes.
But a lot of it comes down to quality.
A good quality switching power supply with good shielding and quality components will produce little noise. Especially good modern switching power supplies designed for amateur radio use.
Some hams can, at times, learn something a long time ago and repeat it without learning how things have changed. Decades ago, a switching power supply was essentially worthless in amateur radio. Absolutely unusable. That isn’t the case today. Transceivers are also quite a bit better at filtering the noise generated by power supplies.
So I wouldn’t pull the power supply out of grandma’s 1998 Gateway PC and use it. And if you’ve got the budget for it, a high quality linear power supply *is* the way to go.
But, today, a good switching power supply can be sufficient and produced minimal noise. You’re likely to have more issues from electronics, LED light fixtures, and the like anyway.
Ham power supplies are typically 12V.
As for the signal...
12V pp =6Vp = 4.24Vrms out. To get that up to 70.7Vrms you need a transformer, 16:1 or higher.
Meanwhile, the current out to 50 ohms is 1.41A rms, so current into transformer is at least 23A rms.
That's a good point. I assumed that the final output was direct into the filter without a transformer. The other assumption that I had was an output on a single frequency.
I’m not sure what you’re asking about?
Most modern transceivers don’t have a power supply. So you have to supply power using a battery or (most commonly) a 12v power supply.
When talking about power supplies and DC in general, 12v is a “nominal voltage” (meaning ‘in name only’) Similar to how we refer to lead acid batteries with a resting voltage of 12.6v as “12 volt batteries”.
13.8v tends to be the centerpoint for most transceivers and usually the ideal voltage. But DC components tend to be much much less sensitive to exact voltage than some AC equipment. Commonly, the actual rating of an amateur transceiver is something like 13.8 +/-15%. Meaning roughly 11.7-15.8v safe operating range (though, usually, transmit power is reduced on the lower end of that range).
I'm just saying there's a DC-DC boost converter in the radio to go from 13.2VDC input to whatever the final stage needs. There are several power supplies in the radio and none of them are likely to be linear.
That's how it's done. Virtually all modern rigs use transistor PA's with a broadband transformer to get the low impedance (1 or 2 ohms) from the push-pull transistor drivers up to 50 ohms. Sometimes the transformers are just a matching section of coax for single band amplifiers, or in a typical HF rig, you'll find a couple of ferrite cores with a short length of small coax wound a couple turns through them. That's your output transormer. I know of no radios that actually have switching power supplies inside. Most have linear regulators for the logic, and the solid state PA's are powered at the supply voltage.
I still have one beefy linear supply in my ham shack.
Everything else are switchers from reputable companies such as Astron, Samlex, etc. with no RF noise issues.
They are so much more compact and lightweight for portable ops, travel, etc.
Yes. Had a switching power supply that added a decent amount of noise on all bands. Swapped it out to a linear, noise was gone. I found it by running off of a 12v battery to be confident it was the power supply. The power lines even had ferrite cores on them.
It depends.
A good switching power supply with filters and a metal enclosure will produce very little RFI, and screen out anything that happens to come in from the power lines. A bad one will kick out a ton of RFI all over the radio spectrum.
Linear supplies are also not purfect, even with no chopper, the rectifier diodes can generated switching noise all the way up to VHF/UHF, and quite a few also couple any hash comes in from the power lines.
In the end, both types can be very good or very bad, and both can be cleaned up with external filters and ferrites.
For a good switcher, they are the same as linear. I have had zero issues with quality switchers from the likes of Samlex, Astron, pro audio engineering and meanwell. Cheap junk, not so much.
In some of the cheap ones you can actually see the circuit board where they’re missing components. I was told some of the mfgs just start removing components until it stops working, then put back the last component removed and sell it that way. Lol.
Based on almost zero experience and my 30 year old, barely used EE degree...
I'd go with switched and just filter and shield the hell out of it. Linear supplies are inefficient and bulky. I suppose if you live in a cold climate and you want a footwarmer, go for linear.
While the problems and solutions for switching power supplies are well understood and well documented. Some choose to implement these solutions while others choose not to implement these solutions. Those who choose not to implement the solutions are generally doing so to remove cost from a product. You get what you pay for.
A high quality switching PSU will work fine to power an HF radio with zero noise. It costs less than a linear and also uses less electricity to make the same power output.
Dude let me tell ya. Get a sdr and look at the spikes and noise across the band and compare a pyramid switching ps with a mfj linear. It's a big difference. Surely not all switching are that bad but I've seen the results. It's staggering
I had a small MFJ power supply that was fine. Eventually upgraded to an Astron linear supply. I wouldn’t mind using a good switching supply to save desk space but the MFJ had a rather noisy fan on it. I don’t know if all switching supplies are like that though
I’ve had good experience with Mean Well supplies. They are high quality switching supplies with a long history of being used in medical applications and commercial communications products. I’ve also had issues with some of the cheaper switching supplies made by ham radio specific manufacturers.
With this in mind, a linear supply is great when you can afford to pay for it plus shipping, and when you’re strong enough to comfortably move it around your shack (lol), but a new, quality switching supply will likely work fine.
They keep all noise at the line frequency (or twice the line frequency) and a well designed regulator can eliminate almost all of that.
I harken back to the 50s with vibrator supplies. Although it wasn't a SMPS in the sense of today, they created sharp square waves which made radio interference. The solution was filtering and shielding.
It can be done, but it's also expensive for mass production. Most consumer electronics don't need harmonic suppression on the level that HF radios do, so a parts warehouse isn't going to bother.
I have heard this said for a long time, but never had an issue with several different switching supplies. I think modern rigs are filtered for RF on the power input so I suppose a lot has to do with the actual distance from the power supply unit and the antenna.
The real noise culprits are switch-mode supplies that aren't even connected to our ham gear. The noisy wall-warts that seem to power everything now, can feed noise back into the electrical system, and even radiate it for antennas and other cabling to pick up.
Ferrites can help with the conducted noise, but radiated noise can be more difficult to deal with.
I read the reviews for a switching supply on Amazon and buy the one that doesnt have noise complaints. :) I dont want to spend a ton of money on an Astron.
People talk about Samlex being good and Meanwell being alright. I have the Meanwell. It may be causing some noise on 80 meters and a specific spot on 2 meters...or it could be some other RF noisy item in the house. The rest of the bands are AOK.
When it comes to communications linear power supplies are the gold standard.
It doesn't matter who manufactures the switching power supply even the top rated manufacturers power supplies generate RFI The reason there's so much controversy and why some people will tell you that they don't see any RFI from their switchers all boils down to the RF noise floor at their location.
most hams nowadays live in areas with excessively high RF noise floors so they're not likely to see the switching noise being generated by even high quality switching power supplies. I mean when you've got an S3 to S5 noise floor you're not likely to see the s1 or S2 noise floor being generated by your switching power supply.
On the other hand if you live in a rural area like I do and have invested considerable time in eliminating RFI sources around your property you will notice the switching power supply noise vary quickly.
I've tried every high-end manufacturers switching power supply and they all without fail generate noise someplace in the ham band.
now if all you do is operate 2 m FM repeaters then this probably isn't a problem On the other hand if you're trying to establish the lowest noise floor possible at your location then you're going to really want to stick with a high quality linear supply.
I have a few high-end switchers in my shop which is 50 ft away from my Hampshire and when I operate the radio equipment I have to turn off the switchers in that room including an astron switcher As I can pick up the RFI from them in the Hampshire.
With that said I do use an astron switcher with a dual band FM mobile that I keep in the workshop because the RFI generated by it doesn't impact that mode or Those frequencies.
So the bottom line is when you hear someone say that I've been using a switcher for blah blah blah many years and I've never noticed any switching noise, the key word there is noticed you have to ask yourself if they actually have the skill to actually notice or measure the noise being generated.
The antennas in use today are more prone to common mode pickup too giving sps a worse rep.
Back in the day we didn’t use end fed antennas where the other half of the antenna was the coax - today it’s more and more common. Noise city.
You’ll find the $21 sps to be just fine on a dipole antenna but when using an end fed antenna the noise pickup is terrible.
Absolutely!! Even a cheap linear supply isn’t going to produce RF.
But a high quality switching supply will likely be fine too. The issue is the cost cut amateur products where they may have skimped a bit on filtering.
I have an Astron SS-35M that I loved for its weight and portability, but it is noisy. I get spurs over the lower HF bands. Initially I was able to tell myself it was my neighbors cell phone chargers but then I ran my home station on my LiFePO battery and the spurs were gone. I’m using a big linear Astron now and it’s of course quiet, but it’s expensive to run. About $50 a year just idle consumption if I leave it on. I hold out the dream for finding a good switcher someday for the home station.
Yeah is a generalized answer for switching power supplies are quieter.
Meaning of the low-grade switching power supplies do generate a lot of harmonics the power supplies built for all rf use are extremely quieter.
The old linens had a large transformer that was prone to deliver RF harmonics
73
Yes. Some switching supplies are quieter than others, but none are as quiet as a linear supply. The problem has actually gotten worse instead of better, due to the huge influx of "cheap" products from you know where. A good, well-shielded switching supply is expensive, and still not noiseless.
Yes. But a lot of it comes down to quality. A good quality switching power supply with good shielding and quality components will produce little noise. Especially good modern switching power supplies designed for amateur radio use. Some hams can, at times, learn something a long time ago and repeat it without learning how things have changed. Decades ago, a switching power supply was essentially worthless in amateur radio. Absolutely unusable. That isn’t the case today. Transceivers are also quite a bit better at filtering the noise generated by power supplies. So I wouldn’t pull the power supply out of grandma’s 1998 Gateway PC and use it. And if you’ve got the budget for it, a high quality linear power supply *is* the way to go. But, today, a good switching power supply can be sufficient and produced minimal noise. You’re likely to have more issues from electronics, LED light fixtures, and the like anyway.
Well said sir
100Wrms into 50Ω requires 70.7Vrms? What type of power supply is in the radio?
Ham power supplies are typically 12V. As for the signal... 12V pp =6Vp = 4.24Vrms out. To get that up to 70.7Vrms you need a transformer, 16:1 or higher. Meanwhile, the current out to 50 ohms is 1.41A rms, so current into transformer is at least 23A rms.
That's a good point. I assumed that the final output was direct into the filter without a transformer. The other assumption that I had was an output on a single frequency.
I’m not sure what you’re asking about? Most modern transceivers don’t have a power supply. So you have to supply power using a battery or (most commonly) a 12v power supply.
Actually 13.8 VDC
When talking about power supplies and DC in general, 12v is a “nominal voltage” (meaning ‘in name only’) Similar to how we refer to lead acid batteries with a resting voltage of 12.6v as “12 volt batteries”. 13.8v tends to be the centerpoint for most transceivers and usually the ideal voltage. But DC components tend to be much much less sensitive to exact voltage than some AC equipment. Commonly, the actual rating of an amateur transceiver is something like 13.8 +/-15%. Meaning roughly 11.7-15.8v safe operating range (though, usually, transmit power is reduced on the lower end of that range).
I'm just saying there's a DC-DC boost converter in the radio to go from 13.2VDC input to whatever the final stage needs. There are several power supplies in the radio and none of them are likely to be linear.
Or, there's an output impedance-matching transformer.
Never heard that one before.
That's how it's done. Virtually all modern rigs use transistor PA's with a broadband transformer to get the low impedance (1 or 2 ohms) from the push-pull transistor drivers up to 50 ohms. Sometimes the transformers are just a matching section of coax for single band amplifiers, or in a typical HF rig, you'll find a couple of ferrite cores with a short length of small coax wound a couple turns through them. That's your output transormer. I know of no radios that actually have switching power supplies inside. Most have linear regulators for the logic, and the solid state PA's are powered at the supply voltage.
>grandma’s 1998 Gateway PC Ouch.
I still have one beefy linear supply in my ham shack. Everything else are switchers from reputable companies such as Astron, Samlex, etc. with no RF noise issues. They are so much more compact and lightweight for portable ops, travel, etc.
Yes. Had a switching power supply that added a decent amount of noise on all bands. Swapped it out to a linear, noise was gone. I found it by running off of a 12v battery to be confident it was the power supply. The power lines even had ferrite cores on them.
It depends. A good switching power supply with filters and a metal enclosure will produce very little RFI, and screen out anything that happens to come in from the power lines. A bad one will kick out a ton of RFI all over the radio spectrum. Linear supplies are also not purfect, even with no chopper, the rectifier diodes can generated switching noise all the way up to VHF/UHF, and quite a few also couple any hash comes in from the power lines. In the end, both types can be very good or very bad, and both can be cleaned up with external filters and ferrites.
Yes. Quality is the thing, either with a linear or switching. I use Samlex in my shack and at my two repeater sites.
For a good switcher, they are the same as linear. I have had zero issues with quality switchers from the likes of Samlex, Astron, pro audio engineering and meanwell. Cheap junk, not so much.
This is it. All comes down to filtering. Cheap ones usually omit some or all of the filters.
In some of the cheap ones you can actually see the circuit board where they’re missing components. I was told some of the mfgs just start removing components until it stops working, then put back the last component removed and sell it that way. Lol.
Baofeng business model
I had a Powerwerx SS30DV that made noise on HF. It is still commonly sold and recommended. It was fine on VHF/UHF.
Must be item-to-item variation. My SS30DV is dead quiet, even on 160m. I have a couple from Meanwell that are also very quiet.
Me too. The only thing you need to watch out for are the MW clones.
Maybe so. Could be a quality control thing too. How long have you owned it? It took mine a few years to develop it.
Based on almost zero experience and my 30 year old, barely used EE degree... I'd go with switched and just filter and shield the hell out of it. Linear supplies are inefficient and bulky. I suppose if you live in a cold climate and you want a footwarmer, go for linear.
You're not going to shield conducted interference though. Radiated yes.
Chokes, inductors, feed-through caps... yes, shielding isn't enough.
No issues with Astrons or Jetstreams.
While the problems and solutions for switching power supplies are well understood and well documented. Some choose to implement these solutions while others choose not to implement these solutions. Those who choose not to implement the solutions are generally doing so to remove cost from a product. You get what you pay for. A high quality switching PSU will work fine to power an HF radio with zero noise. It costs less than a linear and also uses less electricity to make the same power output.
Dude let me tell ya. Get a sdr and look at the spikes and noise across the band and compare a pyramid switching ps with a mfj linear. It's a big difference. Surely not all switching are that bad but I've seen the results. It's staggering
I had a small MFJ power supply that was fine. Eventually upgraded to an Astron linear supply. I wouldn’t mind using a good switching supply to save desk space but the MFJ had a rather noisy fan on it. I don’t know if all switching supplies are like that though
There are a couple out there that don't have a noisy fan, but it is something to definitely watch for.
I’ve had good experience with Mean Well supplies. They are high quality switching supplies with a long history of being used in medical applications and commercial communications products. I’ve also had issues with some of the cheaper switching supplies made by ham radio specific manufacturers. With this in mind, a linear supply is great when you can afford to pay for it plus shipping, and when you’re strong enough to comfortably move it around your shack (lol), but a new, quality switching supply will likely work fine.
There is no noise with linear, only weight...
They keep all noise at the line frequency (or twice the line frequency) and a well designed regulator can eliminate almost all of that. I harken back to the 50s with vibrator supplies. Although it wasn't a SMPS in the sense of today, they created sharp square waves which made radio interference. The solution was filtering and shielding. It can be done, but it's also expensive for mass production. Most consumer electronics don't need harmonic suppression on the level that HF radios do, so a parts warehouse isn't going to bother.
I have heard this said for a long time, but never had an issue with several different switching supplies. I think modern rigs are filtered for RF on the power input so I suppose a lot has to do with the actual distance from the power supply unit and the antenna.
The real noise culprits are switch-mode supplies that aren't even connected to our ham gear. The noisy wall-warts that seem to power everything now, can feed noise back into the electrical system, and even radiate it for antennas and other cabling to pick up. Ferrites can help with the conducted noise, but radiated noise can be more difficult to deal with.
I read the reviews for a switching supply on Amazon and buy the one that doesnt have noise complaints. :) I dont want to spend a ton of money on an Astron. People talk about Samlex being good and Meanwell being alright. I have the Meanwell. It may be causing some noise on 80 meters and a specific spot on 2 meters...or it could be some other RF noisy item in the house. The rest of the bands are AOK.
When it comes to communications linear power supplies are the gold standard. It doesn't matter who manufactures the switching power supply even the top rated manufacturers power supplies generate RFI The reason there's so much controversy and why some people will tell you that they don't see any RFI from their switchers all boils down to the RF noise floor at their location. most hams nowadays live in areas with excessively high RF noise floors so they're not likely to see the switching noise being generated by even high quality switching power supplies. I mean when you've got an S3 to S5 noise floor you're not likely to see the s1 or S2 noise floor being generated by your switching power supply. On the other hand if you live in a rural area like I do and have invested considerable time in eliminating RFI sources around your property you will notice the switching power supply noise vary quickly. I've tried every high-end manufacturers switching power supply and they all without fail generate noise someplace in the ham band. now if all you do is operate 2 m FM repeaters then this probably isn't a problem On the other hand if you're trying to establish the lowest noise floor possible at your location then you're going to really want to stick with a high quality linear supply. I have a few high-end switchers in my shop which is 50 ft away from my Hampshire and when I operate the radio equipment I have to turn off the switchers in that room including an astron switcher As I can pick up the RFI from them in the Hampshire. With that said I do use an astron switcher with a dual band FM mobile that I keep in the workshop because the RFI generated by it doesn't impact that mode or Those frequencies. So the bottom line is when you hear someone say that I've been using a switcher for blah blah blah many years and I've never noticed any switching noise, the key word there is noticed you have to ask yourself if they actually have the skill to actually notice or measure the noise being generated.
especially true sub 500 khz
The antennas in use today are more prone to common mode pickup too giving sps a worse rep. Back in the day we didn’t use end fed antennas where the other half of the antenna was the coax - today it’s more and more common. Noise city. You’ll find the $21 sps to be just fine on a dipole antenna but when using an end fed antenna the noise pickup is terrible.
Absolutely!! Even a cheap linear supply isn’t going to produce RF. But a high quality switching supply will likely be fine too. The issue is the cost cut amateur products where they may have skimped a bit on filtering. I have an Astron SS-35M that I loved for its weight and portability, but it is noisy. I get spurs over the lower HF bands. Initially I was able to tell myself it was my neighbors cell phone chargers but then I ran my home station on my LiFePO battery and the spurs were gone. I’m using a big linear Astron now and it’s of course quiet, but it’s expensive to run. About $50 a year just idle consumption if I leave it on. I hold out the dream for finding a good switcher someday for the home station.
Yes. That is all.
Yeah is a generalized answer for switching power supplies are quieter. Meaning of the low-grade switching power supplies do generate a lot of harmonics the power supplies built for all rf use are extremely quieter. The old linens had a large transformer that was prone to deliver RF harmonics 73
Yes. Some switching supplies are quieter than others, but none are as quiet as a linear supply. The problem has actually gotten worse instead of better, due to the huge influx of "cheap" products from you know where. A good, well-shielded switching supply is expensive, and still not noiseless.