[CQ-Contest] Switching Power Supplies

[charlie at thegallos.com]

I never had an issue with my Samlex, even the older one, and of course my linear Astron works fine, but is  bit on the heavy side

If you want to get a really quiet supply, look for one that is rated for Hospital Medical Equipment – there is a EMC requirement that is very strict

 

From: Barry W2UP <w2up.co at gmail.com> 
Sent: Tuesday, November 12, 2024 8:28 AM
To: Charles Gallo <charlie at thegallos.com>
Cc: cq-contest at contesting.com
Subject: Re: [CQ-Contest] Switching Power Supplies

 

Thanks for all the comments.  To summarize the responses, both to the list and private, the two top recommendations were the Samlex and Astron.  FWIW, I just ordered the Samlex 1235P-M, which is a newer version of the 1235-M, which hopefully incorporates some of the newer designs that Charlie alludes to.

 

Barry W2UP

 

On Mon, Nov 11, 2024 at 8:22 PM Charles Gallo <charlie at thegallos.com <mailto:charlie at thegallos.com> > wrote:

No,
My comment was more along the lines that in the quarter century since that article, I’m sure there are many new models of supply, that it is entirely possible that internally models have changed. It was really really great information on what existed 25 years ago, but how good is it on what exists today?

Reading a lot of the EE trade bags, particularly over say the last 4-5 years, EMI/RFI has become a big topic for switching power supply folks, and the chip makers that now make chips specifically for power supplies have done work to help eliminate some of the issues, and heck, even the printed circuit board design software folks are putting in features to help eliminate the issues.

So yes, great article on what was the state of the ham radio industry at the turn of the century, but how much it reflects today is up for debate
--  
73 de KG2V
Charlie

> On Nov 11, 2024, at 8:04 PM, Barry Jacobson <bdj at alum.mit.edu <mailto:bdj at alum.mit.edu> > wrote:
> 
> Hi Charles, wasn't sure if you were addressing my comment. But thanks
> for the very informative QST article. Wasn't sure what feature you
> were focusing on, but if you look at the spectral plots, all but one
> or two have noise issues in the ham bands. That review is from 2000.
> Maybe things have improved since then, and you could post a more
> recent article. I would be curious. Personally, my hearing is very
> poor so I wouldn't want to take a chance unless I knew for sure the
> model is noise free. Others may not mind for the convenience of better
> portability.
> 
> Best of luck.
> 
> Barry WA2VIU
> --
> Barry Jacobson
> WA2VIU
> bdj at alum.mit.edu <mailto:bdj at alum.mit.edu> 
> @bdj_phd
> 
>> On Mon, Nov 11, 2024 at 10:17 AM Charles Gallo <charlie at thegallos.com <mailto:charlie at thegallos.com> > wrote:
>> 
>> You think that maybe, just maybe, there are new things, and things have changed in nearly a quarter of a century?
>> --
>> 73 de KG2V
>> Charlie
>> 
>>>> On Nov 11, 2024, at 7:57 AM, Ed Goss <ed.n3cw at gmail.com <mailto:ed.n3cw at gmail.com> > wrote:
>>> 
>>> Barry:
>>> 
>>> See:
>>> 
>>> http://www.radiomanual.info/schemi/ACC_powersupply/Power_supplies_review_QST_2000.pdf
>>> 
>>> --Ed, N3CW--
>>> 
>>> 
>>>> Message: 2
>>>> Date: Sat, 9 Nov 2024 18:44:49 -0700
>>>> From: Barry W2UP <w2up.co at gmail.com <mailto:w2up.co at gmail.com> >
>>>> To: CQ-Contest Reflector <cq-contest at contesting.com <mailto:cq-contest at contesting.com> >
>>>> Subject: [CQ-Contest] 12V 30A Switching Power supply recommendation?
>>>> Message-ID:
>>>>   <CACUWneMbC3gksLzOC4Yn3XoEsbKagd-D07Cy94G7B43oaninTw at mail.gmail.com <mailto:CACUWneMbC3gksLzOC4Yn3XoEsbKagd-D07Cy94G7B43oaninTw at mail.gmail.com> >
>>>> Content-Type: text/plain; charset="UTF-8"
>>>> 
>>>> Looking for a recommendation for a 30A 12VDC switcher.  No RFI is very
>>>> important as my antenna is only about 15-20 ft away from the station.
>>>> 
>>>> Tnx,
>>>> Barry W2UP
>>>> 
>>>> 
>>>> 
>>> 
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