Dick,
The current design has too much
unnecessary hardware and access to the inside of the modules is unnecessarily
restrictive. Why not have a full depth machined chassis with a screw-on top and
front plate? That would eliminate the PEM standoffs and lots of hardware plus it
would allow top only access to PCBs. Tolerances for board mounting could be
more closely managed as could overall chassis stiffness. It would also allow
for maximum flexibility in the use of front panel space. Boards could be
inserted from the top or front as desired. We could choose to use front loading
slots for the PCB with fewer screw-in machined standoffs to maximize usable
board area.
Rick
W2GPS
AMSAT
LM2232
From:
[email protected] [mailto:[email protected]] On Behalf Of
Sent: Wednesday, October 17, 2007
7:29 PM
To: 'Chuck Green'
Cc: 'AMSAT Eagle'
Subject: [eagle] Re: Updated
Module
Chuck:
Indeed the machined baseplate width is just 141mm and
the cavity is 126mm wide. I would NOT recommend any PCB to be that full width,
that it be no wider than 140mm, so theoretically you could have a PCB that is 140x180mm.
Perhaps that can be another iteration. (I did not deal with the PCB at all in
this round.) Not tonight honey, I've slugged at this beast for six hours today,
enough already!
-----Original Message-----
From: Chuck Green [mailto:[email protected]]
Sent: Wednesday, 17 October, 2007 21.46
To:
Cc: Bob Davis; AMSAT Eagle
Subject: Re: [eagle] Updated Module
Hi Dick,
This is a good step forward.
I had in mind making the PCB wider so that it extends
over the entire
length of the base plate on each side. It seems
to me that you could
then make the PCB mounting points less intrusive into
the cavity below
the PCB. It looks like I still have that option
even if you don't
change the mounting points (true?). And I think
that would also better
support the PCB and allow for more thermal contact
between the PCB and
the base.
I see that you have more mounting points per linear
distance for the
cover than for the PCB. Is this based on
vibration modeling?
>
> Also note that the depth of the cavity below the
posts is 6.35mm, save
> for in the very center where there is an
attachment for the connector
> plate that is located 0.75mm below the PCB for a
space in the center
> that is 10mm wide by 6mm deep from the connector
plate. I was loathe
> to locate such a piece here but felt the need for
a third attachment
> for the connector plate.
>
Please reconsider this. It will cause
considerable restriction on where
connectors can be located that are also soldered to
the PCB. Connector
space/flexibility is a *major* issue.
Chuck