On 14 Feb 2013 at 13:27, gordon white wrote: > If you find instability at 28 mc, think what it must have been like to > design the layout of the two tuneable vhf receivers, or the R-28, or > the 190 channel AN/ARN-30 receivers. It must have been an absolute nightmare. As I have repeatedly said, I regard ARC engineers as geniuses. Ken W7EKB