Looking to build an HF/Lo VHF RF output stage with GRUNT?
A couple of these in push-pull and around 1KW RF is achieveable
I found some interesting videos online about these, have a look at them.
I also noticed that some hardy souls have been experimenting with these as audio output tubes, creating very high powered mono blocks - do a search around online to read the various experiences when trying this.
These are Mil spec devices, easily confirmed by the reference to DLA (USA Defense Logistics Agency)90089G0028 which was a contract to Varian Associates USA for the supply of electron tubes for military purposes back in 1990-91
https://aad.archives.gov/aad/display-partial-records.jsp?f=1111&mtch=3179&q=B&cat=all&dt=338&tf=F&bc=&rpp=50&pg=9
Amperex
Made in USA
4CX 350FJ 8904 JAN
High Power Tetrode for RF use, usually Class AB
Each tube is capable of 350W Plate dissipation, 2500V plate voltage
IMPORTANT TO NOTE: The FJ suffix denotes these use a 26V heater, not 6V
Specifications are easy to find online for these but basically this is a forced air cooled beastie that is commonly used in high powered RF amplifiers.
Here is just one link to a pdf which provides all the tech info including characteristics graphs http://www.tubecollectors.org/eimac/archives/4cx350a(68).pdf
These tubes are BRAND NEW - supplied in the tin cans, if you see these tubes NOT in the tin cans, they are NOT Mil spec supply.
Both tubes are in their cans, absolutely brand new unused but the rip tab has been removed because I had to check the contents and take the photographs.
If you are looking for 350's then these are the best you can get of this model tetrode from Amperex
