[hpsdr] Pandora Update and Question

[Ben Hall]

Hi Chris and gang!

Chris Albertson wrote:
> I looked at the 3D model on the wiki.  I occurred to me that the only
> truly custom part is the pack panel.

By design.  :)  One of my goals was that we use an off-the-shelf box 
(cheap!), keep the custom parts to a minimum, and then make the custom 
parts usable on their own.

> Any proper size case could
> work as long as the slots on the back matched the cards that are
> plugged into Atlas. 

Another option is to use your own box, buy the custom slotted end panel, 
and fit the end panel to your box.

> Perhaps a cheap way to get this back panel made
> with international distribution is to not make the back panel out
> of sheet metal but from PCB material (coper clad fiberglass.)
> 
> Any of a dozen of the overnight PCB fabricators can make a custom
> board with holes routed the exact shape of the connectors on the
> backs of the various HPSDR cards. The coper cladding makes as good
> a shield or ground as does aluminum sheet.  The real difference is
> that for sheet metal you need a high volume production run to make
> stamping out custom prts economical but PCB makers are setup for
> low volume custom work.  There could be a half dozen design files
> on the web, one panel design for a specific mix of HDSDR cards.

It's an option, that's for sure.  I'm not optimistic that small-run 
circuit boards will be cheaper than small-run metal pieces - I've bought 
small-run boards of my own design from SparkFun (www.batchpcb.com) and 
they've been pretty expensive - like $20 for a 2" by 3" board?  Now, 
I'll admit, I have little pricing data for small-run metal pieces, but 
front-panel express quoted an early prototype slotted end panel at 
around $40 for the whole 9" by 5" (more or less) panel.

I also don't know if the board edges are made to the same tolerances as 
the traces, nor do I know if they can do rectangular punched-out sections.

But, here's one of the wonders of open source.  Once Pandora is more 
mature and has passed some sort of HPSDR design-review, what is to stop 
us from making all the solid models and drawings available to all under 
the open-source license HPSDR uses?  Is there anything to stop anyone 
from taking them, mod'ing them, and producing a custom board of any 
material for their own use?

> I'm thinking of using this technique myself for the front pannels
> of some equipment I'm building for myself.  I occured to me a
> while back that I could etch traces to _much_ closer toleraces
> than I can cut aluminum sheet so why not use my PCB layout 
> software for front panel design?   So if I can do front panels
> why not rear panels with connector cutouts?

I'll admit, I've done something like this.  I made a PCB to hold 
switches that also has vias to act as pilot-holes for drilling the front 
panel.  It's both a PCB for mounting the switches and a high-precision 
drilling template!

thanks much,
ben
-- 
Thanks and 73,
Ben, KD5BYB


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