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

[Bob Brown - WØNQX]

Science at its finest!

--
Thanks in Advance

   Bob Brown, WØNQX

   Kansas City Metro Area

   http://drsm0ke.net

   http://byrg.net

   http://sm0kenet.net

   http://kcdstar.byrg.net

Quis custodiet ipsos custodes?




--

On Fri, Nov 21, 2014 at 11:00 AM, 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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>
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