[time-nuts] The 10811 double oven mystery

[Mark Spencer]

 But cooling / heating systems designed to work over a Wide temperature range (ie. Parts of Northern Canada where outside temperatures of  perhaps -40C in the winter and +35C in the summer are within the relm of possibility) can be somewhat more expensive / complicated than systems designed for mild climates.

I can sort of see why someone might want electronic equipment that could work at -40C especially if the equipment was going to reside in an unattended shelter that was hard to get to.  I realize that in practice this is likely to be difficult (:

Mark Spencer

mark at alignedsolutions.com
604 762 4099

> On Apr 8, 2020, at 7:09 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
> 
> Hi
> 
> Running a hard disk at -40 C is pretty much a no-go sort of thing. Even finding CPU 
> or FPGA chips rated for operation down there is difficult / expensive. DRAM chips with
> the “right” timing … not so much.  Bottom line - the heater / HVAC costs *way* less than 
> designing all that stuff to work over a wide temperature range. 
> 
> Bob
> 
>> On Apr 8, 2020, at 9:58 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>> 
>> 
>> kb8tq at n1k.org said:
>>> Well, based on conversations with the people who designed the part,  the
>>> outer oven’s only function was to take care of a potential cold end  problem.
>>> At the time, the telecom guys were thinking of putting GPSDO’s in systems
>>> with no heating on the enclosures. That idea died when they ran into a
>>> variety of issues with the digital side of things at cold temperatures.
>> 
>> What's the problem with digital gear at cold temperatures?  The only one I can 
>> think of is that electrolytic capacitors stop working when the electrolyte 
>> freezes.
>> 
>> Do signal integrity problems appear when the rise time from CMOS drivers gets 
>> faster?
>> 
>> What sort of warmth did the telecom guys decide they needed?  I live in 
>> California, at sea level rather than up in the mountains.  We get occasional 
>> freezing from radiation cooling on clear nights.  They wouldn't have to work 
>> very hard to keep a box above freezing.  I'll have to look closer the next 
>> time I see some cell phone antennas.
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
>> 
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> 
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