 At 200 MHz, a noise figure of 2.5 (or 4 dB) can be reached with the ECC2000 tube in an optimized "cascode"-circuit with an optimized source impedance.At 800 MHz, tubes like EC8010 have noise figures of about 10 dB or more.Planar triodes are better, but very early, transistors have reached noise figures substantially lower than tubes at UHF.