I tell you what. Its nice to have this group !. Where us could such geeky neerdy guys like us hang out !
Hmmmm..... Well ive a 6909 coming from ebay, who knows what state it is in. Im going to buy a number of 6909's as I can find them. As far as preserving them, hmmmm.... Lots of good discussions here. So as we dont know the pressure in the tube its impossible to say what pressure outside the tube would be best - even if that concept was good at preserving it. Do you think keeping them in a easy gas to obtain might help ? Like nitrogen ? So it seems like cold might be a good idea ? maybe a freezer bad with a bunch of desiccant gel packs to reduce the moisture ? or would the desiccant also absorb the gas mix ? You know, cold will shrink the tube glass ever so much and might change things and allow more gas in/out. Man this is a difficult topic. A good one to know tho as given 100 years all the dekatron tubes, and neon tubes, will be a issue. So good to know to preserve these things as im sure they are fading, if not now for sure in another 50 years. A bit off topic. Ive been playing with the counter today. I have a rubidium freq source from ebay and hooked that to a modern ( 70's ) HP freq counter as its external freq source. I was calibrating the Dekatron freq counter. Amazingly accurate. BUT I cant trim out that last little bit because i run out of trim room. The parts are all in spec, its the crystal aging. Over 50 years it aged out of the trim range. I needed to add a 22pf cap to get it back in range. But it reminds me this gear is decaying. A week ago I replaced the electorlytic caps with wet tantalum as they dont age much. But even carbon comp resistors do age. I think at 100 years old this counter is going to start to reach a point its just not going to be serviceable without total overhaul of all the original parts. Which takes the fun outta it. Except for the caps its currently all orginal parts. I was testing today and it can count at 120khz and not miss one count, over and over and over. The counter has a built in check, and it counts for EXACTLY one second and shows what it counted, so for 120khz you can get a display of (1)20000 over and over and over. Never (1)20001. Dekatron tubes are actually amazingly accurate as long as the circuits around them are well designed and trimmed. Yea I gotta adjust voltages during calibration for best performance at the highest freq and this needs to be done when you replace the ones tube. Im letting the TXO warm up and then im going to calibrate it against the rubidium source and after I do that I will do a vid showing how it does not miss counts and is amazingly accurate. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a31c56ea-6231-41a4-8cfb-97cb552c1f17%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
