[hpsdr] Pandora: Enclosure and Power Supply

[Chris Albertson]

You can fold and bend aluminum sheet metal without expensive
tools.  People used to build airplanes with just hand tools so
surely one could build a box.  It's very labor intensive.  For example
to make the typical three sided cover you first make a hardwood form
then clamp the sheet metal to the top of the form using a
second hardwood block the same size as the top.  You then force the
side down
a little at a time using a hardwood block and mallet.

Many people have built airplanes this way, using hardwood forms
C clamps and a mallet.   A couple weeks ago I made a bracket for an
antenna
from 1/8th inch think T9 aluminum alloy.  Had to use a 5 pound hammer
That stuff is tuff but you can make aluminum parts by hand.  The
trick is to make wooden forms and use clamps

One more thing:  Be sure and radius the edges of the form.
Sheet metal has finite thickness and so has a minium bend radius.



--- Ben Hall <kd5byb at bellsouth.net> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hi Henry and gang!
> 
> Henry Vredegoor wrote:
> > Reading and thinking about power supplies for HPSDR and been still
> busy 
> > with my search for an appropriate enclosure I have come to the 
> > conclusion that I give up on finding a commercial stock enclosure
> that 
> > would fulfill all my wishes/requirements.
> 
> I totally understand - I've been looking and looking and looking at 
> enclosures and the only one I've found so far that stays around the
> $50 
> US target is the Ten-Tec BK-959.  Everything else blows that $50
> target 
> completely out of the water.
> 
> Even the BK-959, which so far is the best cost/performance box in a
> size 
> close to what we need is imperfect:
> 
> 1)  It has shielding issues.  Top and bottom clamshells don't ground
> to 
> the insides of the box.  Ten-Ten suggested a pair of coax braid and 
> lugs; I plan to experiment with a thin strip of metal to make this 
> connection.
> 
> 2)  It's not quite long enough.  If you install six 220mm length
> cards, 
> there is no depth available for front panel controls.
> 
> > Instead I will construct my own enclosure from aluminum angle
> stock.
> > One of the reasons is, that I intend to use linear power supplies
> and 
> > the required heatsinks (with low height fins of 15 mm.) will be
> forming 
> > the sidewalls of the enclosure.
> 
> One of the European tube, I mean valve audio books I have suggests 
> exactly this method, noting that the aluminum angle itself makes a
> good 
> heatsink.
> 
> > It will probably go over my target budget of ˆ 50 for one enclosure
> (I 
> > will build 3 pcs.: TX/RX desktop/portable use 12 Volts, Desktop-RX
> and 
> > -PSU 240 Volts) , but then "I'll have it my way".....
> 
> I've been thinking about separate enclosures too - maybe one for the 
> cards and another for the front panel?  Still incubating ideas.
> 
> > I am now going to try to learn to use AutoCAD to make some nice 
> > drawings.....
> 
> AutoCAD can be hard.  I've got a watered-down 2D version here called 
> AutoSketch (which is somewhat AutoCAD compatible) that is much easier
> to 
> learn...
> 
> thanks,
> b
> -- 
> Thanks and 73,
> Ben, KD5BYB
> 
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Chris Albertson
  Home:   310-376-1029  chrisalbertson90278 at yahoo.com
  Office: 310-336-5189  Christopher.J.Albertson at aero.org

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