Re: [Xylo-SDR] Some design thoughts requested

[KD5NWA <kd5nwa@cox.net>]

I'll second the DIN connectors,they are very reliable, and come in
different sizes, single, and dual connector cards. I have used them in an
industrial environment and they worked flawlessly for years. But I'll go
one more step forward.

The Eurocard standard allows for mix of one 96 pin connector,  two
connectors or even three connectors (not needed). Prototype boards are
cheap, most PCB houses have specials on Eurocard size boards. Card cages
are available for low prices for the Eurocard format

Like Leon said the connectors are expensive but they are self aligning,
and I've seen then for under $3 on the Internet.

Although the PCI is tempting and cheap for the backplane, it's a bus that
is designed for digital logic, all pins are tied to the same pins in all
cards. Prototype cards tend to be large and expensive.

A brief blurb on Eurocards;

<

http://www.yotor.org/wiki/en/eu/Eurocard.htm >

Cheap prototype boards are available for $10 or less, a very important
point, $50 to $60 for a PCI card is very expensive, maybe I'm too cheap,
but the blank board should not cost more than the components.
<

http://www.sbszoo.com/ve6sbs/sale/cct-brds.htm >

Here are some available at Mouse;
<

http://www.mouser.com/index.cfm?handler=data.getPcodes&pcode=BPS%2BPrototype%2BBoards&pcodenumber=85400
 >

Sample enclosure, can be home made from aluminum extrusions.
<

http://www.busboard.net/bps-enc.htm >



At 03:34 AM 1/2/2006, Leon Heller
wrote:

----- Original Message -----

From: Eric Ellison

To: 'Xylo-SDR Discussion'

Sent: Monday, January 02, 2006 5:17 AM

Subject: [Xylo-SDR] Some design thoughts requested

Folks

 

Even since the PIC 4550 days I have been thinking on how we might conduct experiments as well as have a reasonable environment for ?adding? on to the project. The obvious answer is a buss of some sort. I have looked at everything from Simm riser boards to ISA buss stuff. PCI risers might be the way to go since they are inexpensive ($15) for 3 slot extenders. Also in an end product they fit into the L-brackets of a computer case, or 2U mounts. They have ?assigned? power buss? we can use, fairly inexpensive prototyping boards. ($50 - $60), are four layer and designed to minimize intra trace noise. The buss wouldn?t be used for PCI, however it would allow power, (on designated standards based lines), intra board connections, and FPGA, I2C,signals etc.

 

PCI seems to be a little ?large? for what we are proposing, and the product boards would cost more to produce, however, with an established buss we could put a radio on one card, FPGA on another Audio on another etc.

 

$15 Board amongst others:

 

 

http://www.plinkusa.net/riser.htm

 

 

 

 

Am I off the wall here?

 

That's the sort of thing I was thinking of doing. I used to work for Racal and they used to build their military radios from separate screened plug-in modules on a backplane.

 

I favour DIN41612 connectors for this sort of thing. They are expensive, but very reliable, and have pins on 0.1" centres. They can even accomodate co-axial connectors. They are more commonly used in Europe than the USA, but you can get them over there without any problems.

 

73, Leon

--
Leon Heller, G1HSM
leon.heller@bulldoghome.com
http://www.geocities.com/leon_heller
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Cecil Bayona
KD5NWA
www.qrpradio.com

"I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... "