This compensation circuit reduces the reference oscillator's temperature coefficient by as much as a factor of 10 for superior frequency stability over temperature. Upgrade Instructions (E850138 Upgrade Instructions)
Included with all K2s shipped after 4/25/03. (S/N 3446+)
If your K2 serial number is below 3000, we also strongly recommend the installation of the BFO modification kit (BFOMDKT) before the PLL upgrade is installed. (K2s s/n 3000 and up already include the changes to the BFO circuit.) Also, K2 firmware older than 2.00 should be upgraded (FWK2MCIO) to take maximum advantage of the PLL upgrade. Tuning linearity is much improved with the new F/W.