Ahh, well, a few comments clarifications, from a guy with 38 years of experience (HVAC/mechanical and controls engineering) with Carrier air conditioning.
Opening comment (not really my area of expertise, but I do have moderate relevant experience), the heat pain threshold is quite variable (between individuals, and depending on time of day and LOTS of other factors), and the touch test is probably not a reliable predictor of whether the radio is "too hot". My perception is that the Elecraft radios are thermally well protected, but if really concerned, I think measuring temp with an IR sensor and comparing it against published limits might be a preferred approach to assessing it. As to atmospheric pressure and altitude, these are really separate variables. While there is a functional relationship between them, it's not so strong that for most normal activities (i.e. unless the plan is to climb K2, Everest or similar) it shouldn't be a significant factor in the discussion. And FWIW, temp generally decreases with increasing altitude, which then of course lessens an overheating problem by increasing the heat transfer driving delta-T. As to whether it's better to install fans in a blow-thru or a draw-thru configuration, there's no clear winner for this type of electronics cooling application. If condensation was an issue (it's not), the distinction between these might become significant. Given that, the decision between these would generally be based on the mechanical layout and on related testing meant to insure that specific components remain sufficiently cool in worst case conditions. (BTW, no way one could hold his finger on a smooth 100C surface for 10 seconds, and no way that same surface at 100F would rise above the heat pain threshold in 10 sec.) Chris Jones - K2CZ On Wed, Jun 30, 2021 at 9:37 PM Geoffrey Feldman <[email protected]> wrote: > My rule of thumb is that if you can keep your finger on it for a second or > so without pain, it's not too hot. > > > > The ambient temperature is really not the issue as much as whether heat is > carried off. I know it's hot in the pacific northwest but I think you can > still enjoy your gear. The larger issue is RFI from air conditioners. > > > > The environmental consideration many people neglect is atmospheric > pressure. > As altitude increases, there is less air to carry the heat away. People > sometimes install fans with an idea to sucking out the heat. This is > actually wrong. The fan should blow ambient air in and the venting for it > to > get out should intend that pressure inside the case be a bit higher than > the > ambient pressure. More molecules against the hot part, the better. If you > read the fine print on electronic specifications you will often (and should > always) see an atmospheric spec with the heat spec. > > > > All the above is just rule-of-thumb of course. There is a lot more to > cooling electronics than the above but I think these are worth considering. > > > > Elecraft gear is pretty good at protecting itself as well. If your radio > cuts out, it's doing its job of living for more fun later. > > > > W1GCF > > Geoff > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
