Dave:
I'd like to create a page like the U-RX page for this stuff. Couldn't
figure out how to create a noew page; can you? I'd like it to be
reachable both from Requirements and from Mechanical categories.
On that page, I'd like a link to a table where people can EASILY enter
their comments, and then Bob can EASILY enter his resolution thereof.
Can you do this for us? I tried & failed.
(Dick Jansson also sent comments that I'd like to get included)
Thanks & 73,
jim
[email protected]
-------- Original Message --------
All:
Comments from my first quick look:
1. There are many references cited herein. It may be useful to
collect these in a single section titled "References" to which you can
than refer.
2. 6.5: cites machining requirements using MKS units. A year or two
ago, there was an intense discussion about this on the Eagle list, with
many complaining that CNC machines want inches and feet. At that time,
a proposal was made that DESIGNERS be responsible for specifying both
MKS and inches/feet, so that any machinist could fabricate. Request
consider making this a requirement.
3. 6.6: Can we include a link to the reference?
4. 6.10: I don't understand what this is demanding, particularly the
interior chip piece of it. While the need to prevent chips inside is
obvious, it would appear that there is more to this story than is
obvious. Please explain to me, and consider elaborating the
requirement.
5. 6.11: Requests "consideration" of certain factors. This is vague
and unenforceable. Please explicitly state requirements which must be
met and "features" which are desireable.
6. 7.4: Uses the word "generic" but generic WHAT? It appears that a
word or words are missing.
7. 7.5 et seq: What does "TBC" mean??
8. 7.7: If possible, please include a link to the references. This
is valuable information which many should read, and might, if they can
get to it easily. You've obviously done a lot of homework, please
share.
9. 7.8: Please elaborate on what is intended by requiring "access"
for assembly. It is not clear to me what I must do if I am building
one of these things.
10. 7.9: This looks good, but I have one question: Is this
requirement consistent with what Juan Rivera found as a requirement for
board stiffness with SMD devices? If so, please state the
reason/reference. IF there's a discrepancy, let's get it resolved and
publish a common requirement.
11. 7.10: What is "arbitrary stiffness"????
12. 7.12 and 7.13: Should we consider flexibility at one end?
Rationale: Boilers and steam generators which are exposed to
temperatures ranging from 70F to 950F are rigidly mounted at one end,
and have "sliding feet" at the other, which allows for thermal
expansion. In our application, should we consider rigidly mounting one
end of the PCB and allowing the other to move a bit, to prevent stress
buildup which will manifest itself as a bending moment on the PCB,
breaking SMD components? I'm open to better ideas, but based on what
Juan has reported regarding stresses and bending of boards, this seems
like a reasonable idea, given the temperature ranges our boards and
enclosures might see.
13. 8.4: Please define the "standard bolting pattern."
14. 9.1: Please devine "TML" and "CVCM".
15. 9.2, 9.3: Please provide links to the references.
16. 9.5: This requirement is ambiguous. Please elaborate on what is
meant by "solutions." I see the examples, but still don't understand
what I must do if I'm a provider.
17. 9.7 & 9.9: Please define "MS" and "FS".
18. 9.10: Please define "GEVS" and "ASD".
19. Figure 3: Please define "G2/Hz". Hz is understandable, but what
is "G2", and what is the significance of normalizing it to Hz?
20. 10.4: This appears excessively restrictive. What is magic about
the dimensions provided? Is this assuming a 1, 2, or 4-layer board?
Is this assuming a particular dielectric? what happens if a microwave
circuit requires an exotic dielectric and a thinner material to control
impedances and losses. Please provide a rationale for being so
restrictive, or provide guidelines to allow variation in materials and
thickness based on board functions.
21. 10.7: Please explain the rationale for not allowing components on
the side opposite the connector face. (Prohibiting mounting on the lid
is fairly obvious, the back wall is not.)
22. 10.8: Please explain the reason for the 12.55 mm requirement.
23. 10.10: This appears to indicate rigid mounting of connectors at
one end of the module and also to the board. What will we do to
eliminate stress to components and the board
from temperature change?
Bob, this is very good work, and the above is merely questions.
Tomorrow night, I'll attempt to create in EaglePedia a page for this
and a table like for the UHF RX where comments, commentor, and
resolution can all be consolidated in one location.
Thank you for all your hard work.
73,
Jim
[email protected]
Robert Davis wrote:
I'm specifically hoping for comments from this group.
Thanks,
bob
---------- Forwarded message ----------
From: Robert
Davis <[email protected]>
Date: Oct 8, 2007 3:16 PM
Subject: New doc: Eagle Module Mechanical Requirements
To: AMSAT Eagle <[email protected]>
All,
I've posted an initial draft of requirements for Eagle module
mechanical design. Looking for comments. Be gentle since it's my frist
crack at it and there's TBDs.
Thanks,
bob
Robert Davis
KF4KSS