Hi Ed, We routinely test military/space parts at -55C to +125C. The parts are under voltage and monitored throughout the range. Many of the failures at the very low temp ranges may not be permanent. As the temp is raised the device most of the time functions properly again. There are some anomalies though. We have seen some memory devices work fine at -55C and then lose bits around -40C. And then work fine as the temp rises again. At the high temp end there is greater chance for permanent failure.
So, very cold temps can be an issue with any of our gear, especially considering we are using commercial parts. Test temp ranges for semiconductors; Commercial - 0C to +70/80C Automotive - -40C to +125C Military - -55C to +125C 73, N2TK, Tony -----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Edward R Cole Sent: Thursday, October 06, 2016 12:43 AM To: Elecraft@mailman.qth.net Subject: Re: [Elecraft] Cold K3 Dick, The KX3 will not see those extreme cold temps. Where we live it rarely drops below -15F and typically is 0 to +10F at night in winter. The KX3 has a RAM bracket in my truck so it might sit outside at night. I was wondering how it would react to being powered on at down to -15F. Truthfully it might not ever face that as I have remote start for the truck to warm up for winter driving so the cab might reach +20 or higher before I would use it. A few miles driving and the cab should be +50 to 60F which is comfortable wearing a winter coat. More than likely I would just bring the radio inside at night if planning to use it the next day. My experience with the TS-180S was that the cold effected the LCD screen so operating was not possible until it warmed. That experience in 1986 was the coldest I have seen in my 36 years up here in AK. Quite possible the temp dropped to -80F at night (-78F is the official record for AK). Fortunately at extreme cold the air is completely calm most of the time. Dog teams coming into the checkpoint reported -45F on the ridge tops but with 30-40mph winds which would feel much colder than what we were down in the lake valley. The coldest I have experience at home on the Kenai Peninsula is -35F and that was nighttime so I stayed inside near the wood stove. I now live in a modern home with force-air natural gas heat and its +67F to +71F year round. Radio gear is std in all vehicles used at Prudhoe Bay on AK's "north slope" but either they leave the engines run continuously or they are plugged in with electric heaters on the inside keeping the interior from freezing. Ever climb into a suburban when the seats are -40F and hard as a rock (a very cold rock)? In fact the seats split apart if allowed to get that cold. Most repeaters up there are enclosed in warmed buildings and only antenna and coax outside. I had fun up there in Nov.1980 installing MOT radios in heavy equipment that was parked outside (it was only -15F so my bare hands took a punishment). After a couple days one of the operators showed me how to start up the engines and I got a little warmth inside the cabs (+15 vs -15). I was young (36) and adventurous - making $6500 in three weeks working 18-hour days didn't hurt, either. 73, Ed - KL7UW From: Richard Fjeld <rpfj...@outlook.com> To: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net> Subject: Re: [Elecraft] Cold K3 On 10/4/2016 7:16 PM, Edward R Cole wrote: I've not tried running my K3 at outside temps, Hello Ed, I would caution you against trying your K3 in those temps. Minus 60 degrees F. is the coldest on record for Minnesota, and you experience far colder that that. The cold may do multiple things to the K3 if it has multi-layer circuit boards. I didn't notice if it does. Our club left a repeater in an unheated enclosure one winter. I would estimate it wasn't much colder than minus 30 degrees F. at that location. (To clarify for others, this is 30 degrees F. below zero.) I have seen what the multi-layer circuit board looked like. More specifically, the thru-the-hole solder connections from one layer to another were cracked. Maybe it was the type of solder used??? I'm sure circuit designs have changed since the first solid state rigs I described in the cold. LCD screens hadn't been heard of yet. I'm surprised they don't freeze and get damaged in your temps. It is interesting to read of your outdoor experiences. 73, Dick, n0ce 73, Ed - KL7UW http://www.kl7uw.com "Kits made by KL7UW" Dubus Mag business: dubus...@gmail.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to tony....@verizon.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
