Pete, I found the BFO at Surplus Sales of Nebraska http://www.surplussales.com/ Oscillator 452 - 458 kc (RF) AT-7620 R-390A / URR variable intermediate frequency oscillator. Brand new from Artisan. Use for replacement in R390 or for any project requiring a 455 kc IF. NSN: 5820-00-697-9687. $45 each Roger AI4NI</HTML>