Switching power supply noises?

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Rred

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If we could try to confine this to the question at hand, please?

I'm about to pick up a clean used radio that I want to use for HF dx listening. It will need a 25A power supply, and I'm used to the plain old fashioned big heavy analog linear supplies that never had any problems. But, the new digital switching supplies certainly are a lot smaller, lighter, cheaper to ship.

Except I keep hearing that any digital supply WILL have problems, will make noise, will always be a bit of a PITA. If I consider something like an Astron (solid name, arguably) or an Alinco (or the Tekpower which seems to be a dead clone of it) with an "offset" noise for the noise they admit will eventually show up....

What's the groupthink on an arguably "good" switching supply versus just spending the extra cash and getting a good old fashioned big heavy analog supply that might break my toes but never will make a peep?

In both cases, models are 30-35A continuous with a meter. The Tekpower is a whole $99 on Amazon and seems to be reviewed (as far as you can trust reviews) as well as anything else.
 

majoco

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HF dx listening. It will need a 25A power supply,

No it won't. 25A if you want to transmit. IMHO no more than a normal receiver, say 2A from 12volts. Just remove the microphone and make sure that you cannot get into transmit mode by any other means. If you have a long wire antenna it probably won't be tuned so even if you did manage to transmit it would probably shut down due to excessive VSWR.

Avoid switch mode power supplies, a regulated transformer to supply just the receiver won't be very expensive.
 

ko6jw_2

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I bought an Alinco many years ago because there was a test in QST of switching power supplies and it came out with the lowest noise. It was a very nice supply and has an adjustment to move the noise bandwidth if necessary. Sadly, it failed after six or eight years, but I might buy another one. It has a cigarette lighter plug and some from panel low current binding posts.

One point, if you are only listening, you don't need 25A. A 5A supply (probably less) will do.
 

N4KVE

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It's a hard question to answer, as a switcher could make noise on one rig, but not another. I have accumulated many switchers. Astron, MFJ, Samlex, & DuraComm. While none of these make any noise, I use them on VHF/UHF mobile radios, & have tested none of them on HF radios. For HF I always use a 19 pound 35 amp Astron.
 

Rred

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Majoco-
"No it won't. " Try taking what I said at face value, I didn't say it would need 25A to receive, I said it would need a 25A supply. You've already figured out one reason why the radio might, at some time with some users, require 25A. Accept, don't assume imaginatively, please.

So on vhf/uhf, no matter. But on HF, where I'm interested...
So far one vote and that's for analog linear. Gary, was your switcher too low an amperage for the HF? Or noisy?

I'd go analog but assembling the parts and finding time to build (properly) could take me a month or two longer than I want to wait right now. Unless I get lucky and find the parts I've long had but simply mislaid somehow.
 

N4KVE

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No. Basically I live in Condo Land now, so I can't use HF. Before I lived here, I used the big heavy Astron, but had no switchers until I moved here. So I never had a HF radio, & switching supply at the same time.
 

Rred

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Condoland, yes, may they all rot in hell, subject to a 2/3 vote on which air conditioning system and vendor to use.(G)

I'm hearing that magnetic loops or quad loops or quagis may provide some relief for that, if you're willing to have a four foot wide pipe sculpture standing someplace. Tried? Or just not worth the effort?
 

N4KVE

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I still have my old antenna. If I can't use it, I'm not willing to compromise, & use something smaller that wouldn't be as good as what I have.
 

K3EP

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Rred - I was wary of buying a switching PS, but wanted one for portable operation (mostly vacation). I did quite a bit of research (including a QST article that rated it and other PS) and decided on the Samlex 1235M, and I have not been disappointed. I have detected no noticeable noise on any of the HF ham bands. My 2 cents.

73
 

prcguy

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I have several Astron switchers like the SS-18, SS-25M and SS-30 and have had no noise issues on HF. I've probably had the SS-18 for at least 15yrs and its my main travel supply for 100w HF. Its only rated at 18A but I've pulled over 20A for very long periods of time and it does't seem to care. I only paid $40 for it on Ebay and it was used when I got it. For awhile Tentec used to sell a rebranded SS-18 for their 100w HF radios.

A 100w HF radio in SSB mode only draws an average current of 6 to 8A depending on how dense the transmit modulation is. I've run 100w radios in SSB from an 8A supply and it works but your on the edge if you have the mic gain up very far.
prcguy
 

Rred

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Thanks, guys. There seem to be a lot of contradictor results, which probably mean "I hate spinach", so to speak. Different uses, users, equipment...lots of room for different results even with the best of design and manufacture.

I'd also heard of Samlex from some folks who used their high power inverters. IIRC a Canadian company importing Chinese electronics that are sold under several brands. I'd heard they were good, but with varying qc in the usual "Chinese best export to the wide eyed barbarians of the lower realm" quality. Of course that's neither the first or last place qc problems come from, we have enough on domestic goods.

Whichever one I roll the dice for...same thought on portability. If a 4# box or a 20# box has to travel with me, I think I can tolerate some issues in order to save carrying 16#.(G)
 

N0IU

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Except I keep hearing that any digital supply WILL have problems, will make noise, will always be a bit of a PITA.

You're listening to the wrong people!

I have a Ten Tec 941 switching power supply (which unfortunately is not made any mode) and it is definitely NOT a PITA in any way. When I sold my Ten Tec radio, I kept the power supply and have been using it with an Icom IC-7410 for almost 3 years.

So the bottom line is to get a quality power supply and it WON'T have problems, WON'T make noise and WON'T be a PITA!
 
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