On 5 Oct 2013 at 17:36, J. Forster wrote: > Bigger ships used the RDO. I have a pic, if you want. I have at least one complete RDO plus a collection of tuning units for it/them....if you want them. ;-) The RDO weighs at least 100 lbs. I also have an APR-1. No APR-4s though... Ken W7EKB