[eagle] Re: CAN-Do Suggestions from Juan
juan-rivera at sbcglobal.net
Tue Jul 17 16:28:44 PDT 2007
You could be correct although I wouldn't call it butchered. I enlarged the
holes using my milling machine, a few thousandths of an inch at a time. But
aside from the altered state of this base plate I think there are other
issues to address. It may come to pass that two compartments are required
to deal with the radiated EMI from the CAN-Do module. I think it will be
very hard to partition this enclosure into two RF-tight compartments using
sheet metal. I also think the AVX guide specifying no more than 0.0038"
flex in any one-inch segment of the PCB might be hard to meet with this
enclosure. AVX is one of the largest manufacturers of ceramic chip
capacitors in the world so I believe they know what they are talking about.
If anyone disagrees and wants to put out another argument for maximum SMT
PCB flex I'd be interested to see it.
Anyway my opinions are just that. Once the dust settles and there is an EMI
requirement and a PCB flex requirement, a determination can be made to see
if the existing enclosure meets the requirements. If it does then there is
no need to change it. That removes all the subjective opinions out of the
decision loop. You hold everything up to the peer-reviewed requirements,
run some peer-reviewed tests, and either it passes of it fails. The same
goes for the CAN-Do module and the Receiver. At least that's the way I'm
used to doing things at work.
From: Dick Jansson-rr [mailto:rjansson at cfl.rr.com]
Sent: Tuesday, July 17, 2007 11:36 AM
To: 'Juan Rivera'; 'Chuck Green'
Cc: 'David Smith'; 'Dave Black ((Work))'; 'Dave Black ((Home))'; 'Louis
McFadin'; 'AMSAT Eagle'; 'Samsonoff at Mac. Com'; 'Juan.Rivera ((Work))'
Subject: RE: [eagle] Re: CAN-Do Suggestions from Juan
You keep commenting on the flexure of the PCB and relate it to the module
hardware that you have in hand. It is my very greatly considered opinion
that the baseplate that you have has been modified (butchered) to allow for
the soldering of the CAN 40pin connector and this has created not only
reduced sections in this plate, but probably has also distorted the plate
considerable. Such distortions in all likelihood have created a non-normal
flexure condition in that particular plate. As such, your opinion of the
design has been biased, and that is unfortunate. It seems to me that you
should try to acquire an E05 21 base plate that is in "stock" condition. I
don't have any in hand here in Florida, or I would have sent it to you some
time ago. These parts, unfortunately are in a limited supply at this time.
Dick Jansson, KD1K
kd1k at amsat.org
kd1k at arrl.net
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