Hi All... Some interesting semi off topic discussions of late, very interesting.
Re the water in plastic bottle problem. (I seem not to have seen the original message, there again we've had transient email/isp problems here recently) A "Vacuum" formed by any migration of the contents will not distend (expand) a bottle, but will cause it to collapse in on itself. Water and plastic container combinations in general can be interesting, if just due to the process of Osmosis, dependant on the contents and container materials. (Ask any owner of an elderly GRP boat about that!) Water and some metal combinations are known problem points too, unless you use extremely pure water and choose your metal (and closure methods) carefully. I also suspect a good quantity of light grade synthetic or silicone based oil would do almost as well, and be electrically inert and not react with the container or the materials used in the electronics, so long as the exact material used was chosen with care. However, it will take a system much longer to reach thermal equilibrium, the larger the thermal mass it has. Or as someone else suggested, use a Glass container. So long as you don't want it to last for many 100's of years, as Glass is not a solid, it is a "super cooled fluid" and as such it flows like Ice over time, just that it takes much much longer to do so! Oh, and make sure it has some thermal expansion relief (a gas pocket or an intentional "mechanical soft spot") Just a thought. I remember hearing of a UK amateur many years ago, who had a remote tuneable VFO for (I think for 80mtrs) buried some feet underground in his garden, to achieve thermal and frequency stability. And that was using Valve (Tube) technology too! It was powered 24/7 of course, but I do not know any other details. However, it was said that his signal was one of the most stable (frequency wise at least) on the band in those days (the 70's if not the 60's) I do not know how it was remotely tuned, and it's not exactly a portable solution either! Regards to all. Dave B. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
