12v DC power supply question


Woody Schlom <woody@...>
 

Recently somebody (I think it was Roland) suggested that what we want is
a good quality regulated SWITCHING power supply.

Why a SWITCHING PS instead of an old-fashioned transformer PS? I
thought that even though transformers are much much heavier and larger,
they were in general cleaner.

The 12v PS I used to use with my Mach1 and camera was made by Pyramid --
with a very heavy transformer inside. A couple of years ago I put that
one in my mobile observatory -- where it is now. And I bought a second
one just like it for portable use with my Mach1 and camera.

But that "new" PS has a serious problem (I mentioned in another post
this evening). So I bought a new switching PS. I like the new one
because it's so much smaller and lighter and has built-in PP
connections. But it has a "noise adjuster" knob to hopefully minimize
noise for HAM radio use. The fact that it even has such an adjustment
tells me there's a problem with noise in at least this switching PS.

Any comments?

Woody


Dean Jacobsen
 

Woody, 

I don't know about the "noise adjuster" knob on a communications grade switching power supply.  I haven't ever seen one in any of the power supplies I have used but I have used Astron brand switching power supplies and Astron linear power supplies for decades with my ham radio gear and my astro gear without any problem.  I use the switching power supplies for the portable astronomy gear that I take out to the club's site because they are easier to lift in and out of the truck.  My 20 amp switching power supply is quite a bit lighter than my linear power supply.  

There is an outfit here in San Diego called Ham Radio Outlet.  They could set you up with a nice linear or switching power supply... whichever you prefer.

Dean Jacobsen


Christopher Erickson
 

Modern switching power supplies use a frequency of about 20Khz to 2Mhz
instead of the old-school 60hz to change voltages from one level to another.
The higher the frequency, the smaller the transformer and filter components
can be. This saves in weight and cost and can increase conversion
efficiency, resulting in less heat generation (energy loss).

The down side is that the switcher frequency range is in the medium-wave &
shortwave radio spectrum bands and can cause primary and harmonic
interference for ham gear at certain frequencies placed close to the
switcher. Having a switcher with an adjustable frequency is sort of a cool
feature that would really appeal to ham radio enthusiasts and shortwave
listeners.


-Christopher Erickson
Observatory engineer
Summit Kinetics
Waikoloa, HI 96738
www.summitkinetics.com

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
Sent: Thursday, October 19, 2017 5:34 PM
To: A-P GOTO Mounts Yahoo Group
Subject: [ap-gto] 12v DC power supply question

Recently somebody (I think it was Roland) suggested that what we want is a
good quality regulated SWITCHING power supply.

Why a SWITCHING PS instead of an old-fashioned transformer PS? I thought
that even though transformers are much much heavier and larger, they were in
general cleaner.

The 12v PS I used to use with my Mach1 and camera was made by Pyramid --
with a very heavy transformer inside. A couple of years ago I put that one
in my mobile observatory -- where it is now. And I bought a second one just
like it for portable use with my Mach1 and camera.

But that "new" PS has a serious problem (I mentioned in another post this
evening). So I bought a new switching PS. I like the new one because it's
so much smaller and lighter and has built-in PP connections. But it has a
"noise adjuster" knob to hopefully minimize noise for HAM radio use. The
fact that it even has such an adjustment tells me there's a problem with
noise in at least this switching PS.

Any comments?

Woody



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Posted by: "Woody Schlom" <woody_is@...>
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