[Elecraft] power supply

Fri Nov 1 12:12:04 2002

Hi

Linear supplies are better in that they do not generate any RF. The probl=
em is they are large, heavy, not very efficient and they are getting expe=
nsive. All that iron and copper and large pass transistors that are requi=
red for a good linear supply costs a lot of money. With the computer indu=
stry using millions of switchers the cost has come down on them and gone =
up on linear supplies. Early switchers were terrible in the RF area but t=
he newer ones use sine wave switching circuits that do not generate all o=
f the harmonics that the early square wave switchers had. Most of the swi=
tcher specifically made for ham radio are quite good with little or no ha=
sh. However they will never be as good as a linear or a large battery, af=
ter all they are nothing but a low frequency transmitter with a rectifier=
 and a lot of filtering.  =20

Don Brown
KD5NDB
----- Original Message -----
From: Mike McCoy
Sent: Friday, November 01, 2002 10:21 AM
To: Elecraft Reflector
Subject: Re: [Elecraft] power supply

All my supplies are of the linear variety. What is it that makes switchin=
g
supplies so attractive and/or preferable to a linear design?

Wouldn't using a (decent) linear supply solve any/all concerns about hash=
?

Mike - K5PU

----- Original Message -----
From: "Kenneth E. Harker" <[email protected]>
To: "Elecraft Reflector" <[email protected]>
Sent: Friday, November 01, 2002 9:29 AM
Subject: Re: [Elecraft] power supply

> On Thu, Oct 31, 2002 at 10:46:53PM -0500, Jeff Burns wrote:
> > I am comparing the MFJ 4125 power supply to the Samlex SEC-1223 and t=
he
> > Astrom SS-25. Any helpful comments would be appreciated. This will be
used
> > to power a K2/100 eventually.
>
> There was a Product review article in QST in Jan 2000 that reviewed (I
think
> these very same models of) switching power supplies.  The Astron and MF=
J
> supplies performed well.  The Samlex supply did not.
>
> http://www.arrl.org/members-only/prodrev/pdf/pr0001.pdf
>
>

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