I was not aware, though I should have been, that Rick enacted an org
chart through the BOD before I "returned from the dead". Anyone I have
been calling AVP Eng. (Bob Davis, Jim Sanford, and Lou McFadin) are now
engineering directors. I like it better myself now that I think about
it more carefully. I just wanted to be prickly and argue about it for
the sake of arguing since it is different from what was done before I
went into the cold!
Bob
--
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
“An optimist may see a light where there is none, but why
must the pessimist always run to blow it out?” Descartes
Eagle team members:
Bob Davis, Jim Sanford, and I met in Pittsburgh as the engineering
executive team and we made some changes. Bob and Jim are Asst. VP
Engineering and continue to remain in those offices until such time as
they do not wish to hold them or another AMSAT opportunity interests them.
The office of project manager does not exist as of the annual meeting. I
do NOT want this read the wrong way. There are some delicate
negotiations that are about to take place with multiple entities. For
all sorts of reasons, none of them having a single solitary thing to do
with ego, performance, etc. require the person speaking on behalf of
the project, for its budget, and direction must reside in the VPE.
As of the annual meeting and the budget passed by the AMSAT BOD, the
only projects receiving funds in 2008 are RF payloads, antennas, SDX,
ACP, and the Eagle structure. The Eagle structure is going forward
because it serves multiple purposes. No funds will be expended on any
of those systems that are unique to Phase 3 satellite systems since our
goal, to put RF payloads on Intelsat, does not need solar panels,
attitude sensors, attitude control mechanisms, etc. We are going to
need to hold some meetings soon. I will call for them shortly.
As much as some of you disliked either the tone or approach of
functional requirements and specifications, we are without choices now.
We are going to have to talk to and work with some fairly serious
engineering firms or offices about getting payloads built that will last
for 15 years. We cannot do less than this and expect anyone to give us
the millions of dollars this program is going to take. That said, I
believe we can raise this money.
Expect more to follow shortly.
Bob
--
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
“An optimist may see a light where there is none, but why
must the pessimist always run to blow it out?” Descartes
Hi all,
I've updated our CAN-Do project web-site with new content
See: http://can-do.moraco.info/
Various top-level pages which you navigate to using the links
along left column have "<- New" marks in yellow to
denote the updates.
Of particular interest is the new material found linked from our
reference page.
Designing a Module or Payload which uses a CAN-Do widget?
-----------------------------------------------------------------------------------------
You will want to make sure you have reviewed the updated
Widget User's guide I've posted for review (linked from the
reference page.)
See the revision history in the guide for what's new.
If you would like to see corrections made, or additional
material added please let me know.
Regards,
Stephen, KZ0Q
--
kz0q(a)amsat.org
(formerly kc0ftq)
I have (finally!) put the finishing touches on my magnum opus describing
my ideas on phased arrays and shipped it off to be included in the
Pittsburgh symposium proceedings. If you want to see it, it is available
for viewing at
http://mysite.verizon.net/w3iwi/electronic_scanning_antennas.pdf. This
version has some figures in color, but the proceedings is in B&W (this
format is available if you need it).
This took me a lot longer than I anticipated. I had a couple of fairly
major Gates-induced computer failures, some of which still plague me
(like I'm using my notebook for all Email). I advise against the use of
Office 2007.
I am hoping that this week I will have time to test Dan's hardware so I
can have some results to report by Pittsburgh.
Matt -- this has the numbers I was trying to remember last weekend.
For all -- your comments and critiques are solicited.
73, Tom
All:
I have the display computer which will be used to show presentations
during symposium.
If you can, please get them to me early. I can accommodate a "stick",
CD, or DVD.
I'll be in the BOD meeting and "around"today and tomorrow.
I can be reached at my cell, 757 869 7892.
73,
Jim
wb4gcs(a)amsat.org
John:
This will be my concluding note on this subject prior to the Symposium. I
have tuned the analyses done yesterday and that data follows.
For a single 1.4mil ground plane with a single IC located 52mm from the
Baseplate edge, a 1.0W dissipation results in a temperature rise of 38.2°C
For a double 1.4mil ground plane with a single IC located 28mm from the
Baseplate edge, a 1.0W dissipation results in a temperature rise of 21.1°C.
For a double 1.4mil ground plane with TWO ICs, spaced 40mm and both located
28mm from the Baseplate edge, a 1.0W dissipation in each IC results in
temperature rises of 26.1°C (one at 26.0 and the other at 26.2). Total
dissipation here is 2.0W.
In other words, doubling the ICs, with this spacing, only added ~24% to the
temperature rise. This shows you how this module design handles the kind of
power situations that you have in the URx.
See you in Pittsburgh?
73,
Dick Jansson, KD1K
<mailto:[email protected]> kd1k(a)amsat.org
<mailto:[email protected]> kd1k(a)arrl.net
John:
I have just completed some analytic evaluation of the clamping of the PCB
generously to the side edge of the Baseplate, as in the revised design shown
to you on the E05 60 Module, its new designation.
The model consists of a 80x80mm PCB, with 72x80mm freely hanging away from
the Baseplate. One model uses only a single 1.4mil copper ground plane layer
and has the IC mounted 52mm from the clamped PCB to the Baseplate. The
second model uses a dual 1.4mil copper ground plane and has the IC mounted
20mm from the clamped PCB to the Baseplate.
I ran a series of four power levels in the IC, 0.25W, 0.50W, 0.75W, and
1.00W. The IC temperatures are fairly linear with power for each case. In
the first case with the IC mounted pretty far away, 1.00W of power caused a
temperature rise of 38.4°C above a 20°C Baseplate and enclosure. For the
more closely mounted IC, the temperature rise for the 1.00W case is 28.6°C
above the 20°C of the Baseplate.
You can detect that the temperature rise does not seem to be very linear
with the distance from the Baseplate. As this data is still quite new for
me, I do not have an explanation for this effect. I did, however, want to
make you aware of the data so that you can start to plan to see what you can
do in the URx redesign. I plan to do some variations on these two cases to
try to understand the processes more completely. I do, however, have to wrap
up this data process so that I can complete my presentation in Pittsburgh.
I hope that this information will be of use to you.
73,
Dick Jansson, KD1K
<mailto:[email protected]> kd1k(a)amsat.org
<mailto:[email protected]> kd1k(a)arrl.net
Bob:
Attached is drawing E05 64, 140x180 PCB. This is being sent out for your
review, prior to being posted on Eaglepedia. This PCB gives more working
area with fewer interruptions to the working area (just essentially two
posts). Please look at this and forward any corrective comments.
'73,
Dick Jansson, KD1K
<mailto:[email protected]> kd1k(a)amsat.org
<mailto:[email protected]> kd1k(a)arrl.net
Bob:
Shown in this message is a picture of the revised module design that you and
I have been working on in the last few days. The revised cover has not yet
been done but its features are implicated in this current view. The machined
base plate has robust beams around three sides. Further, there are
stiffening beams machined on the bottom side of the baseplate. The side to
side dimension of the baseplate is shown at 141mm, reduced from its previous
147mm. This step was needed to accommodate the cover screw heads now on the
side of the module.
Shown also is a revised connector plate, which is increased in width from
the previous 122mm to the 141mm of the baseplate. This should ease the
connector space issue a little as the cover PEM nuts have accordingly been
moved out leaving a 125mm wide clear space for connector activity, an
increase from 106mm.
The PCB is unchanged, however its standoff posts are now 6.4mm (1/4 inch)
from the previous 4.8mm (3/16 inch), a step needed for connector plate
screws.
The cover will slide over the assembly shown and it will have only one
flange, along the rear side. The long sides will use screws placed into the
edges of the assembly (formerly a flanged side). This means that there will
not be mechanical loading on the baseplate caused by irregular flange bends,
as in the present cover design.
Regarding this design of module, the PCB access has been fully maintained,
but the cover cannot be removed while the module is installed into the
spacecraft, a feature that had been planned with the current design.
Discussion is invited.
Dick Jansson, KD1K
<mailto:[email protected]> kd1k(a)amsat.org
<mailto:[email protected]> kd1k(a)arrl.net
125x180 Module Assembly.jpg
Bob:
Owing to the "popularity" of these discussion, I have done further revisions
of the E05 20 Module. It is now officially termed a "140x180" module as the
PCB has grown to that size. The size increase has allowed an increase in PCB
working area to a clear 126x173.6mm, 6.35mm deep, save for three protrusions
- two support posts and the third at the front to accommodate the third
connector plate screw (this later post is not in contact with the PCB as
explained earlier). The three attached PDF files show the module with its
cover attached, cover removed and PCB and cover removed.
I shall shortly be able to issue a drawing of this revised PCB.
The cover has further been simplified as the rear mounting flange has been
removed and replaced by side-inserted screws, as is for the cover's sides.
Chuck has properly noted that such a mounting of the PCB will enhance the
thermal characteristics of the PCB. I plan to combine an earlier PCB thermal
analysis and this new PCB configuration and expect to be able to identify
the power handling capability of this PCB without the use of any added heat
sinks. The enhancement should certainly be available along three sides of
the PCB. That data should be available for the Symposium.
Dick Jansson, KD1K
<mailto:[email protected]> kd1k(a)amsat.org
<mailto:[email protected]> kd1k(a)arrl.net
