So, being the cheap guy that I am, I couldn't bring myself to pay for an expensive commercial environmental chamber, so I converted an old chest freezer by bypassing the thermostat. The compressor now runs continuously which permits it to get well below zero. Once it gets below zero, you don't want to try to restart the compressor since it probably won't restart, so I just let it run all the time.
For cycling and temperature control, I actually have an 1500W electric heater on a PID temperature controller inside the chest. So the compressor is always pumping heat out, and the heater adds enough to maintain a temperature inside. Totally non-energy efficient for sure. But it works, and was cheap. Been thinking about adding the whole liquid Co2 thing to it to help it cool down faster though.... The cooling cycles aren't as fast as I'd like. -forrest On Wed, Mar 9, 2016 at 10:29 AM, Chuck McCown <[email protected]> wrote: > I had to build on once when I was at Carlson. We didn’t have one and some > of the northern latitude customers were complaining that things were > failing at low temps. Took a chest freezer and stuck the end of a tube > into it that was connected to a tank of carbon dioxide. It would certainly > get cold. Once I had my head in the thing, butt up head down doing a test > or install or something. Almost blacked out. And nobody else was in the > shop at the time. > > *From:* Ken Hohhof <[email protected]> > *Sent:* Wednesday, March 09, 2016 10:20 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] 450 14.1.2 build 4 > > Nice environmental chamber. Back when I worked on outside plant telecom > equipment, my chamber would struggle and finally reach –40. Either it was > old, or more likely that was the limit of the type of refrigerant it used. > -55C is pretty cold. > > *From:* Aaron Schneider <[email protected]> > *Sent:* Wednesday, March 09, 2016 10:54 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] 450 14.1.2 build 4 > > > Yes, I was facetiously joking that a fix for the issue would be available > around March 21st in the Northern Hemisphere without a SW upgrade. :) > > > > But, we were able to reproduce it at room temperature a lot during our > investigation, so while colder temperatures do make it worse, it is not > wholly tied to that. > > > > The open beta load that is coming on Friday has been running for several > days now with no issues on multiple setups, including temperature > chambers. One of them has been cycling from -55C - +55C sitting at each > extreme for multiple hours. So, we are quite confident in this one. We > have also had some customers heavily impacted by the issue trying out the > test loads and they have reported success as well. Previously, the image > wouldn’t last more than a few minutes at extreme cold, or more than a day > at room temperature in our room temperature torture setup. > > > > So, I apologize for the lengthy delay, but a fix is coming soon! > > > > Regards, > > -Aaron > > > > *From:* Af [mailto:[email protected]] *On Behalf Of *George Skorup > *Sent:* Monday, March 07, 2016 10:22 PM > *To:* [email protected] > *Subject:* Re: [AFMUG] 450 14.1.2 build 4 > > > > The watchdog thing is definitely tied to temperature. Haven't seen a > single AP reset in days now. It'll be 65 tomorrow! Then I'm sure it'll get > below zero again and snow a foot before we get spring for real. :( > > Will 30MHz on the regular 450 be available in the 5.4 band? Or will that > require a new certification? > > On 3/7/2016 10:06 PM, Matt Mangriotis wrote: > > Aaron hasn’t jumped on this one yet… so let me. > > > > We’ll have a new open beta build of 14.1.2 out late this week (Friday). > We have high confidence that this will eliminate the watchdog. > > > > Among other things, it rolls in ALL of the 13.4.1 benefits and fixes > (including the RADIUS issue you mention) and opens up 5.2 and 5.4 GHz bands > for 450i. > > > > You will certainly want to try this one. > > > > There is also a chance that shortly after, we’ll have a beta of R14.2, > which will have 30 MHz channel bandwidths for 450/450i and enable the AUX > port on 450i. > > > > Matt > > > > *From:* Af [mailto:[email protected] <[email protected]>] *On > Behalf Of *Sean Heskett > *Sent:* Monday, March 07, 2016 3:17 PM > *To:* [email protected] > *Subject:* Re: [AFMUG] 450 14.1.2 build 4 > > > > 13.2.1 is in my opinion the latest and stable release for the PMP450 & > PMP430. 13.4 has some radius and watchdog reset issues (amongst others) > > > > -sean > > > > > > On Mon, Mar 7, 2016 at 1:57 PM, Tyson @ Internet Communications Inc (ICI) < > [email protected]> wrote: > > 14.1.2 is buggy. 13.4 seems stable > > > > > > *Tyson Burris, President Internet Communications Inc. 739 Commerce Dr. > Franklin, IN 46131 * > *317-738-0320 <317-738-0320> Daytime #* > *317-412-1540 <317-412-1540> Cell/Direct #* > *Online: www.surfici.net <http://www.surfici.net>* > > > > Forgive the brevity, the typos and my fat fingers! > > > On Mar 7, 2016, at 3:55 PM, George Skorup <[email protected]> wrote: > > I have 13.4.1 for FSK loaded on a couple sites now. Seems to be good so > far. I wonder how hard it would be to get us 13.4.1 for the regular 450, > with the AP FPGA image that fixes the crazy issues. C'mon Cambium.... I can > dream, right? > > On 3/7/2016 1:49 PM, Sean Heskett wrote: > > i'm too scared after the 14.1.1 fiasco we went through. > > > > let me know how it goes lol...I might upgrade a couple months after 14.1.2 > is out in the wild but i'm too gun shy now. > > > > -sean > > > > > > On Mon, Mar 7, 2016 at 11:12 AM, Tyson @ Internet Communications Inc (ICI) > <[email protected]> wrote: > > Testing the following firmware. We see on three sites using 10Mhz > channels the sms are registering. No issues on 13.4 or 20Mhz channels. > Anyone else see this ? > > > > > > *Tyson Burris, President Internet Communications Inc. 739 Commerce Dr. > Franklin, IN 46131 * > *317-738-0320 <317-738-0320> Daytime #* > *317-412-1540 <317-412-1540> Cell/Direct #* > *Online: www.surfici.net <http://www.surfici.net>* > > > > Forgive the brevity, the typos and my fat fingers! > > > > > > > > > -- *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] | http://www.packetflux.com <http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux> <http://twitter.com/@packetflux>
