[eagle] Re: Updated Module

Rick Hambly (W2GPS) w2gps at cnssys.com
Thu Oct 18 04:47:48 PDT 2007



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







From: eagle-bounces at amsat.org [mailto:eagle-bounces at amsat.org] On Behalf Of
Dick Jansson-rr
Sent: Wednesday, October 17, 2007 7:29 PM
To: 'Chuck Green'
Cc: 'AMSAT Eagle'
Subject: [eagle] Re: Updated Module




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!


Dick Jansson, KD1K

kd1k at amsat.org  

kd1k at arrl.net  


-----Original Message-----
From: Chuck Green [mailto:greencl at mindspring.com] 
Sent: Wednesday, 17 October, 2007 21.46
To: Dick Jansson-rr
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.




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