Some non-inductive resistors do not have the coating that protects from the oil. Those will rise in resistance over time.
This article has more than you ever wanted to know about the Cantenna and modern equivalents. http://www.orcadxcc.org/content/cantenna_va7jw.pdf <http://www.orcadxcc.org/content/cantenna_va7jw.pdf> wunder K6WRU CM87wj http://observer.wunderwood.org/ (my blog) > On Sep 17, 2015, at 8:15 PM, Don Wilhelm <w3...@embarqmail.com> wrote: > > My "gallon size" dummy load is not a Heath, but that was inspiration for > mine. I came across a bunch of 620 ohm 20 watt carbon resistors a long time > ago. > I wired 12 of them in parallel and put them into a gallon can of mineral oil. > That dummy load still measures 51 ohms over the bands from 80 thru 10 meters > with a minimal amount of inductance - and it is over 40 years after I first > built it. > > I figure since it will do 240 watts in open air, in the oil, it should take > the legal limit for relatively short periods, but I have not subjected it to > more than 500 watts. > > Yes, I have heard stories about how the Heath resistors changed value, but my > 'substitute' has not changed over the years. > > 73, > Don W3FPR > > On 9/17/2015 10:36 PM, Fred Jensen wrote: >> Strangely, these non-inductive resistors do not last forever. When I came >> home from SE Asia to Houston in 67, I filled my Heath with mineral oil >> [interesting story on a Sunday], and it measured 51 ohms DC. Today, it >> measures 74 ohms DC. >> > > ______________________________________________________________ > 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 wun...@wunderwood.org ______________________________________________________________ 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
