Don, I don't know why but this has stuck a curiosity point in me. Do you know anything about the pressure in these tubes? I'm sure the mercury vapor rectifier tubes are supposed to be vacated of air, but what is the mercury vapor pressure and what is the difference in pressure from cold to hot. I wonder if it is just a result of a vacuum leak that causes some type of corrosion on the anode. Also I wonder what the gas pressure is in the 3B28 type gas rectifiers and what the density of the gas is. Maybe it is possible that in the gas rectifiers the gas may actually seal or push the atmosphere away from any leak. In any case I bet that if mercury tubes where heated from day one on, that they would have many more hours of good operation.
Science fiction? Maybe the reason they need several days for heat up and then slow anode voltage increase is to force air out that has accumulated over years of setting cold. This might not be possible in a vacuum rectifier but in a mercury rectifier it might be that the mercury vapor pressure might displace enough of the air forcing it back out 5the hole it came in enough to allow it to work or perhaps the lengthy time is just causing a more homogenous mix of the vapor and atmospheric gasses. Science fiction? John, WA5BXO ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.