[App_rpt-users] Frozen repeater -- Deep Freeze test

[Michael Lussier]

Nice ! 

Sent from an iPhone 5 iOS 8

Mike.Lussier at gmail.com
AE4ML at arrl.net
AE4ML at amsat.org




> On Nov 21, 2014, at 12:00, David McGough <kb4fxc at inttek.net> wrote:
> 
> 
> Hi Mike (& Everyone),
> 
> I ran an "experimental" freezer test over the last 10 hours or so. My test
> setup is a "bare" BBB (no case or anything) with URI plugged in, sitting
> in a ceramic dinner plate on the 2nd shelf from the top of the
> deep-freezer. I'm powering the contraption using an Adafruit 5V2A
> wall-wart located outside the freezer, with the small power cord running
> thru the freeze door seal.
> 
> An uncalibrated analog thermometer inside said about -20 degrees
> Fahrenheit just now. The typical range on this thermometer is about -15 or
> lower.
> 
> I brought an industrial "point and shoot" IR thermometer back from my 
> office and checked the BBB at various spots. The CPU/SoC was the warmest 
> at about -2 degrees. Other spots ranged as low as -9. When I pointed the 
> IR thermometer at my old analog one, the IR said -17 (analog says -20). 
> The plate, BBB and thermometer are in the air stream from the freezer 
> circulating fan--that should be a worst case scenario!
> 
> I'm already getting some dirty looks about "commandeering" the freezer!  
> I'll going to conclude this phase of testing before lunch! HiHi!
> 
> 
> 73, David KB4FXC
> 
> 
> 
>> On Fri, 21 Nov 2014, David McGough wrote:
>> 
>> 
>> Hi Mike,
>> 
>> Was the URI green LED flashing (I guess not...)??
>> 
>> I'm rather amazed that the BBB or URI was directly the cause of the 
>> lock-up, even with really cold conditions. The simplest low-power-budget 
>> solution to keep this hardware warm is a simple Styrofoam container. 
>> Even with the minuscule BBB power consumption, Styrofoam should do the 
>> job fine.
>> 
>> I'll mention here, again, that the ONLY scenarios I've seen where BBB's 
>> have locked-up were due to 5VDC power woes. I completely stable 5V power 
>> source is critical. And, the 5VDC regulator might be a source of problems 
>> in extreme cold, too.
>> 
>> If you don't already have it, I recommend adding a cheap digital 
>> thermometer to your cabinet that records all-time temperature extremes, 
>> including time/date. Or, if you want to get fancier, the BBB AllStar 
>> release already includes support for a USB attached thermometer (see the 
>> "pcsensor" command) which will log temperature to a file, etc. Note that 
>> if you decide to go the USB thermometer route, a bug was found in the code 
>> in the 1.2.1 release. This has already been patched, but, you'll need the 
>> patch (contact me off list or search the arm-allstar list for more 
>> details).
>> 
>> Any idea how cold it got and for how long??? And, what is your power 
>> source??
>> 
>> I'm preparing to put a "test" BBB and URI in my deep-freezer (about -15
>> degrees Fahrenheit) for this weekend. I'll put it in there completely
>> unprotected.
>> 
>> My problems in the past with such extreme cold have been issues directly
>> with the radio hardware (like VCO's that unlock, etc.).  This type of
>> extreme thermal shock can also destroy transmitter PA's, in short order by
>> cracking ceramic substrates in power modules, etc. (I've got a few of 
>> those Tee-shirts, too!).
>> 
>> 73, David KB4FXC
>> 
>> 
>> 
>> 
>>> On Thu, 20 Nov 2014, Michael Lussier wrote:
>>> 
>>> 
>>> I went up on the mountain Wednesday morning. The repeater was powered up as well as the BBB. No action from the repeater. 
>>> Any thoughts on low power way to keep the BBB and the URI warm ? I can use 12vdc 
>>> 
>>> Sent from an iPhone 5 iOS 8
>>> 
>>> Mike.Lussier at gmail.com
>>> AE4ML at arrl.net
>>> AE4ML at amsat.org
>>> 
>>> 
>>> 
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>