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[TenTec] Switching Power Supplies

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Subject: [TenTec] Switching Power Supplies
From: "John Ferrell" <jferrell13@triad.rr.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 15 Mar 2010 11:36:15 -0400
List-post: <mailto:tentec@contesting.com>
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 I think that is an outdated rumor.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
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Sent: Sunday, March 14, 2010 3:00 PM
Subject: TenTec Digest, Vol 87, Issue 14


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Today's Topics:

  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@gmail.com>
Subject: [TenTec] power supplies
To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Message-ID:
<5e898ae11003131355q11bc0b7cq69e0890f78852f78@mail.gmail.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


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Message: 2
Date: Sat, 13 Mar 2010 17:31:05 -0500
From: Phil Sussman <psussman@pactor.com>
Subject: Re: [TenTec] power supplies
To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Message-ID: <1268519465.4b9c1229e9990@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@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




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Message: 3
Date: Sun, 14 Mar 2010 11:35:27 -0500
From: "Lyle Dunlap" <qskqrq@grics.net>
Subject: Re: [TenTec] power supplies
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Message-ID: <52850AA63A42405FB446C4B989917635@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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