[TenTec] Switching Power Supplies

[John Ferrell]

I keep hearing that switchers are noisy. I think that is an outdated rumor. 
I have had an MFJ-4245 switcher for about ten years now. I have never 
encountered any noise with my Pegasus or the Jupiter that followed it. I run 
the whole station from it with no problems. It is light enough to hold out 
at arm's length with one hand.

I have never loaded it beyond about 20 amps though.
John Ferrell  W8CCW

"A nation of sheep will beget a government of wolves."
-Edward R. Murrow
----- Original Message ----- 
From: <tentec-request at contesting.com>
To: <tentec at contesting.com>
Sent: Sunday, March 14, 2010 3:00 PM
Subject: TenTec Digest, Vol 87, Issue 14


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> Today's Topics:
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>   1. power supplies (Michael Goins)
>   2. Re: power supplies (Phil Sussman)
>   3. Re: power supplies (Lyle Dunlap)
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> Message: 1
> Date: Sat, 13 Mar 2010 15:55:22 -0600
> From: Michael Goins <wmgoins at gmail.com>
> Subject: [TenTec] power supplies
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
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> I'm looking for a 35 amp supply for the Jupiters and leaning heavily
> toward old-time transformer supplies (probably an Astron). Bought one,
> but it turned up dead when it arrived, so looking for another until I
> have time to do the needed repairs  I know some of the TenTec supplies
> are switchers - but worried about noise as I have a really low noise
> floor here. Opinions, please?
>
> Michael Goins, k5wmg
> Professor, Writing
> University of Texas at San Antonio
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 13 Mar 2010 17:31:05 -0500
> From: Phil Sussman <psussman at pactor.com>
> Subject: Re: [TenTec] power supplies
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Message-ID: <1268519465.4b9c1229e9990 at webmail.pactor.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Typically switching power supplies are much cheaper to produce and
> weigh less (due to the lack of that heavy transformer). Unfortunately,
> the 'switchers' actually produce more noise (including harmonics), but
> are easier to filter.
>
> Older supplies (in my opinion) are less immune to fluctuations in input
> with respect to surges and spikes. However, the older units tend to
> pull more current and are less efficient than their newer cousins. Also,
> their regulation can be sluggish and prone to output transistor overload
> failures.
>
>>From the noise point of view, filtering older units is a lower frequency
> problem whereas newer switchers have higher harmonic output.
>
> In reality; however, both should work without problems unless abused or
> overloaded.
>
> Good luck!
>
> 73 de Phil - N8PS
>
> -----------
>
> Quoting Michael Goins <wmgoins at gmail.com>:
>
>> I'm looking for a 35 amp supply for the Jupiters and leaning heavily
>> toward old-time transformer supplies (probably an Astron). Bought one,
>> but it turned up dead when it arrived, so looking for another until I
>> have time to do the needed repairs  I know some of the TenTec supplies
>> are switchers - but worried about noise as I have a really low noise
>> floor here. Opinions, please?
>>
>> Michael Goins, k5wmg
>> Professor, Writing
>> University of Texas at San Antonio
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 14 Mar 2010 11:35:27 -0500
> From: "Lyle Dunlap" <qskqrq at grics.net>
> Subject: Re: [TenTec] power supplies
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <52850AA63A42405FB446C4B989917635 at your4dacd0ea75>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Good analogy Phil, I use several of both.
>
> Lyle W9FCX
>
>
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> End of TenTec Digest, Vol 87, Issue 14
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