!mPR!?F the equipment did not become available until the last stage of the design work was nearing canpletions This prohibited my attempt to rack-mount the componeti units. The greatest problem that was presented in the tiitial 6~08 of design was the @ and orientation of the antennas to be used. The AN/TRC-l was designed for use of horizontalbeam array antennas. The instructionbook recommendedthat no coasial oable run exoeed 150 feet and that the antennas be spaced at least 50 feet ap!mt. miously this was not feasible aboard the MT. MCKINLEY. Inasmuch as we did not have sn equipment to experimentwith we deoided to stay within tie recommended length of ooaxial oable run and obtained our spacing, so as to reduce interference,by mounting Vertioal di-poles in suoh a manner that the reaeiving array 18 direotly over the transmittingarray and Spaoed around one and a quafier wave length. Using thi8 orientation of antennas, frequenoy spaolng (effectivelyphysical spacing as fir as mutual interferenceis oonoerned) over a band of 30 megaoyoles is possible. Thus by eeleoting the proper frequenciesmutual interferencewas eliminated. The only available site for this type of an array casisting of fi~e sets of antennas was the SG radar ‘pig stick” on the main mast. This brought to light auother problem. Just forward of this site was an SK radar antenna which, with an old type of reflectorwould fire into the AN/TRC-l receiving array. Permissionwas requested from the Bureau of Ships to replaoe the SK radar reflector with a smaller type. This permissionwas granted and the alteratiaoleared the receiting arrays. 1 Section XI 89 -.