Ulrich, The 1200 #1 is built into a GR1115B that had a defective oscillator assy. It could be that the power supply and or the EFC tuning circuit which is hooked to the manual adjust pot is causing the difference. If I get a chance I'll pull the oscillator and retest it and se what happens. I do however have a 1000A that is being tested in the same setup as the "good" 1200 and so far it is not doing very well. Also I meant to thank you for your help with your plotter program and the added decade value Allen deviation you installed. It has made the testing a lot easier. Best Regards, Corby Dawson ____________________________________________________________ Bills adding up? Click here for free information on payday loans. http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3m3aOdw2zJYUhRN8ZONwp40YEDAkEVmGNBVkCGzEi4FUFq97/