On 11/6/2011 2:05 PM, James Cole wrote: > Has anyone ever heard of a Yardney Spot Tuner? Yup. I placed an overview at http://aafradio.org/docs/C-131.html that provides the background and operation. The control boxes for the spot tuner to work with the ART-13 are shown at the bottom of http://aafradio.org/flightdeck/box.htm 73, Mike