[hpsdr] JANUS Updated (again)

[Alex]

The only problem with the drawings is the orientation of the card. PCI cards have thie main component side facing AWAY from the ATX connector. ISA cards have the main component side facing the AT power connector. (I just opened the hood on a couple of my computers to verify). So that bracket isn't going to work.

If we want to keep the component side facing the power connector (ISA) we should use a bracket format like this
http://www.bracketsource.com/ME-507-2AT-B.htm

If we want to reverse the orientation and make the component side face away from the power connector (PCI), then we need a bracket like this
http://www.bracketsource.com/ME-440-2AT-BB.htm (BACKSIDE BRACKET MOUNTING)
or this
http://www.bracketsource.com/ME-390-2AH-B.htm (FRONTSIDE BRACKET MOUNTING)

Alex, N3NP

----- Original Message ----
From: Philip Covington <p.covington at gmail.com>
To: Lyle Johnson <kk7p at wavecable.com>
Cc: hpsdr at hpsdr.org
Sent: Friday, May 26, 2006 9:55:10 AM
Subject: Re: [hpsdr] JANUS Updated (again)

***** High Performance Software Defined Radio Discussion List *****

On 5/26/06, Lyle Johnson <kk7p at wavecable.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Well, phooey.
>
> Looks like I have Janus backwards, for ATLAS to be arranged like Phil's
> drawing suggests!  This is based on Steve's latest drawing and my closer
> examination of ATLAS.
>
> The PCB layout is looking at the board from the *top* (component) side.
>   Phil's drawing actually looks at the board from the *bottom* side.
> Thus, the PCB layout should have the IO connectors on the right as you
> look at the layout, not on the left as shown in Phil's plan view.
>
> My apologies to the group.
>
> Nonetheless, I'd like some feedback on the design just completed.  Not
> about choice of IO connectors, but on noise considerations, ground path,
> signal flow, etc.
>
> And, if anyone knows where you can get blank PCI bus brackets, it would
> be useful to have a detailed drawing showing where default mounting
> holes should be.  I see a nice bracket at SIIG
> <http://onlinestore.siig.com/shopexd.asp?id=543> but no dimensions.
> This bracket <http://www.bracketsource.com/ME-391-2AH-B.htm> has
> dimensions but not indication where the PCB fits in relation to it.
>
> Steve, I'll take a closer look at things and try to match your DIN
> connector location vis-a-vis the PCB outline, mirror imaged, of course,
> to take into account the left-right foo-pah.
>
> Depressed in Mt Vernon

Hi Lyle,

Yep, I have already eaten half a bottle of Excedrin today... LOL...

IF the DIN41612 is mounted on the component (top) side of the board
AND we orient the ATLAS in the ATX case so the ATX power connector is
in the recommended place (near the power supply) THEN the board is
like an EISA/ISA board as the mounting bracket is concerned.

The other thing we need to think about is how we are going to handle
mounting the external connectors in the brackets.  Keystone (Mouser
carries a lot of them) has a lot of different cutouts, but using
standard ISA bracket cutouts will dictate where those connectors are
placed.

I was trying to do a fast drawing of the 100x120 card with exact
locations of the DIN41612 this morning but keep getting interrupted by
work items (I hate when that happens) and I am leaving for Canada at
11.00 AM EST.  Probably won't get it done...

Steve's drawing looks correct as far as the DIN connector offset from
the external connector area, but the DIN41612 is reversed (a1 b1 c1
should be towards the external connector area).  If the board is
oriented so the external connector area is on the left side of the
board and the DIN41812 is on the bottom edge of the board, you are
looking at the BOTTOM side of the board not the component (top) side.

73 de Phil N8VB
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