[eagle] Re: Revised Module Suggestion

Bill Ress bill at hsmicrowave.com
Tue Oct 16 09:13:13 PDT 2007

Hi Chuck,

Yah - what happened to all this talk of "openess" in the Eagle design 

Bill - N6GHz

Chuck Green wrote:
> Hi Rick,
> That's news to me.  What is this secret group you called "We" and when 
> do they intend to include the rest of the Eagle community?  Also, where 
> should I ship the parts that were purchased for the IHU?  The developers 
> of this new IHU may be able to use some of them.
> Chuck
> Rick Hambly (W2GPS) wrote:
>> Chuck,
>> I think there is a good chance that the IHU will be redesigned for Eagle. We
>> are discussing some important changes like switching to an open core instead
>> of the ARM core, changing the oscillator design, and other improvements. If
>> that is done it will be a modest leap to a new board size.
>> Rick
>> W2GPS
>> AMSAT LM2232
>> -----Original Message-----
>> From: eagle-bounces at amsat.org [mailto:eagle-bounces at amsat.org] On Behalf Of
>> Chuck Green
>> Sent: Tuesday, October 16, 2007 11:15 AM
>> To: Dick Jansson-rr
>> Cc: 'AMSAT Eagle'
>> Subject: [eagle] Re: Revised Module Suggestion
>> Hi Dick,
>> When considering special needs, don't forget that the IHU has already 
>> been designed and will need a box to accommodate it. You did this once, 
>> but with the new box designs, it may need to be done again.
>> Chuck
>> Dick Jansson-rr wrote:
>>> Juan:
>>> There is another issue that comes to mind regarding "specialized" 
>>> modules. In a program such as Eagle we will need to create an 
>>> acceptable module design that is useful for many applications in the 
>>> mission and then turn on the fabrication machinery for producing these 
>>> long before the electronic forces are ready to populate them for 
>>> flight. On P3D in 1992-3 we gambled and manufactured a very many 
>>> module parts, expecting that we would have some spares left over - 
>>> wrong! Even with this quite large quantity of parts (and at that time 
>>> there was criticism that we were making too many) we ran out before 
>>> flight and had to make some more.
>>> Fabricating module parts for this program is a guessing game, with 
>>> some estimates of needing to construct up to 80 sets of parts, and 
>>> that may not be enough. You can do the detailed program mathematics 
>>> and come up with some number and I will be willing to bet that you end 
>>> up on the wrong side of that guess. It's a dicey game.
>>> The lesson in this is that we must create a generic module design and 
>>> hardware that can be adapted for many different assignments in the 
>>> spacecraft. Save for your specialized need, we have no indication of 
>>> any other specialized module needs. This is why I prefer to adapt a 
>>> generic module to your needs with the added heat sinks, rather than 
>>> make just a specially machined device just for your needs. And if we 
>>> do, we will probably not have enough of them. This is why I prefer to 
>>> have a generic module design and then carefully adapt it as required 
>>> for specialized module needs. We will be flying more than just the U 
>>> receiver!.
>>> '73,
>>> Dick Jansson, KD1K
>>> kd1k at amsat.org <mailto:kd1k at amsat.org>
>>> kd1k at arrl.net <mailto:kd1k at arrl.net>
>>> *From:* wa6htp at gmail.com [mailto:wa6htp at gmail.com] *On Behalf Of *Juan 
>>> Rivera
>>> *Sent:* Monday, 15 October, 2007 15.38
>>> *To:* Dick Jansson-rr
>>> *Cc:* Bob Davis; AMSAT Eagle
>>> *Subject:* Re: [eagle] Revised Module Suggestion
>>> Dick,
>>> That looks nice! It appears to solve the issue of getting that front 
>>> panel at exactly 90 degrees to the baseplate and also increases the 
>>> stiffness of the baseplate. Increasing the useful front panel space 
>>> also eases the problem of working around the CAN-Do PCB with all of 
>>> the necessary I/O connectors.
>>> Would it be possible to customize the baseplate for the few modules 
>>> that draw high power? It would be nice to machine the baseplate and 
>>> heat sinks as one chunk of metal instead of the existing method of 
>>> having several individual heat sink pieces. I would like to see the 
>>> PCB laying flat on top of the baseplate with milled cutouts to 
>>> accommodate any devices attached to the bottom side. In a perfect 
>>> world there would be no components on the bottom and the PCB would 
>>> make contact with the baseplate across the entire surface. Another 
>>> possibility that might be worth considering would be the ability to 
>>> include "U" shaped heat sinks that would bridge over the top side of 
>>> hot components and attach to the baseplate through holes cut into the 
>>> PCB on either side of the component. Thermal gap filler could allow 
>>> room for CTE mismatches so that the device isn't crushed.
>>> 73, Juan - WA6HTP
>>> ------------------------------------------------------------------------
>>> _______________________________________________
>>> Via the Eagle mailing list courtesy of AMSAT-NA
>>> Eagle at amsat.org
>>> http://amsat.org/mailman/listinfo/eagle
>> _______________________________________________
>> Via the Eagle mailing list courtesy of AMSAT-NA
>> Eagle at amsat.org
>> http://amsat.org/mailman/listinfo/eagle
> _______________________________________________
> Via the Eagle mailing list courtesy of AMSAT-NA
> Eagle at amsat.org
> http://amsat.org/mailman/listinfo/eagle

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