[amsat-bb] Re: [Mw] Request for conceptual design info--cooperative microwave effort CC-Rider

[Cliff Buttschardt <k7rr@xxxxxxxx>]

Doug McGarrett wrote:
> 
> At 07:54 PM 10/8/2005 +0000, Cliff Buttschardt wrote:
> 
>>This month many highly useful microwave, communications conferences
>>are in progress***************snip********
>>
>>http://www.amsat.org/amsat-new/eagle/documents/cc-revisited_paper.pdf
>>
>>If we were to allocate individual tasks, they might be these:
                   **************snip*********
> 
> I would guess that the first step is determining what power supply
> voltage is available, and at what current.  Everyone responding to the
> original post will need to know, at a minimum, the voltage, and
> whether or not it is regulated and/or filtered.  If there is more
> than one voltage available, then what are they, and what quality are 
> they? 
> 
> The second specification that needs to be addressed is the operating
> temperature.  Is the space vehicle heated?  Anyway, that needs to
> be looked at.  Some semiconductors will simply cease to function at
> certain low temperatures.  I can attest to that personally.  (I never
> could figure out the mechanism, but it was real and repeatable. At
> about -15 C, as I remember, these  op-amps typically failed. 
> They were QPL, but rated at 0~50 or so, and that's what they did.
> Warm them back up again, they worked.  Weird.)
> 
> I do not see myself designing anything for the project, but I would 
> be happy to critique the designs, if passed by me.  I am a retired 
> RF engineer, with some experience in microwave "stuff," most recently 
> in the 1 GHz region, but also at 2.4 GHz, and once at 12 GHz (passive).
> I don't know anything about space capability, however.   
> 
> I should think that a couple of others on this list would be happy to 
> do likewise--K2RIW, for one, and Jerry Klekker, whose call I don't 
> remember.  When I was working, engineers used to do a review of new 
> designs, and every once in a while, we found something that could be 
> improved. Not very often--we had good engineers--but sometimes. So a 
> second  or third look is worth it. Particularly when you can't go and 
> fix it!
> 
> --wa2say

Doug, for the present, at least until we get a brassboard going well, I
would make the assumption of terrestrial operation only.  Probably zero
to 35 C would be adequate.  As for power supply voltage and current,
anything reasonable would do since this is FIRST to be a conceptual
earthbound relay.  In that fashion we retain microwave interest and
progress toward spacecraft hardware after proof of initial concept.
     Cliff K7RR
----
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