Hello SBARC,
As some of you know, I have a connection to a radio club in Havana after visiting Cuba twice in 2014-15. Hams in Cuba have very limited access to equipment, supplies and tools but they make do amazingly well with what they can access. However, some things cannot be easily improvised, and vacuum tubes are one such commodity.
My friend Joel CO2YQ is in need of a 527B tube. Here's what he said (translated):
"I need to find out with the colleagues of the Santa Barbara Club, if someone has a 572B valve that I am not using and can donate it to me, my linear is somewhat old a FL2000B and the valves it has are already very low emission."
If anyone has a 527B that they would be willing to contribute, please let me know and I will bring it down to Joel's shack. I will be headed to Havana at the end of the month (Jan 23-30) for a documentary film scout and I could bring it then.
You can read more about my initial contact with Joel and visiting his station in QST: https://levi.maaia.com/qst-journal-of-the-arrl-qsl-from-cuba/
73 K6LCM