Dick,
Following up on my reply, here's a shot of a right angle SMA connected to the type of PCB mount connectors we're using:
This happens to be a straight cable-mount SMA connected to a right angle adapter, but the size is the same either way. It looks like we'll need about 25 mm of space on the side of the module to get the four RF signals in and out.
73,
Juan - WA6HTP
-----Original Message----- From: eagle-bounces@amsat.org [mailto:eagle-bounces@amsat.org] On Behalf Of rjansson@cfl.rr.com Sent: Saturday, June 30, 2007 6:33 AM To: eagle@amsat.org Subject: [eagle] Mocule Connectors
John & Juan:
Your EMI problems certainly do present considerable difficulties. Your
suggestions of placing connectors on multiple faces of a module run
counter to the whole module mounting plan for Eagle. The modules are
mounted with only about 1.5mm clearance at the flanges and only about
16mm clearance on the sides. The "rear end" of the module is also
difficult as there is just not that much space for cabling and
connector access. Mechanical designers in the past have been raked over
the coals for not providing sufficient connector access. The curren
plan allows about 100mm (I don't have the drawings with me at the
moment) of space between facing columns of modules for the cabling and
connector access. This is a plan that is pretty basic to the whole
wiring plan for Eagle, and it is a result of a lot of experience with
P3D.
While the basic module design for Eagle, unlike P3D, does not provide
for the stacking of modules, a small CAN module placed on top of the
URx, could be considered. Wiring to this sub-module would be by means
of jumper leads from its connector face into the URx.
I caution that there currently is not planned for much space above the
rows of modules as the current spaceframe plan has the modules placed
fairly closely under the solar panels. This concept is part of the need
to keep the mass moment of inertia, Izz, high. This is NOT just a
desirable feature, but a necessary, MUST need for the spin stability of
the spacecraft. So any top-mounted sub-module would have to not be very
thick.
All of these issues arise from the practical considerations of the
overall mission of the spacecraft. Unfortunately for the EMI and
other "local" issues, we cannot design the spaceframe only for EMI, but
must solve other mission requirements, too.
I am not trying to be unmovable on the design if the URx, but I am
trying to explain how we can have a successful mission.
'73,
Dick, KD1K
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