[4) \ Use of inefficient transmitting antennas. In order to avoid changing antennas when frequencies were changed and also to r I obtain omni-directional radiation for certain ship-shore and air-ground circuits, a Navy-designed two-wire terminated sloping folded diPole was used. Fourteen of these were erected. The design is admi.ttedl.ya compromise, sacrificing radiation efficiency to obtain a non-resonant characteristic. For certain circuits this antenna worked acceptably; however, for those where the omni-directional feature was not required and where the numbar of choices of frequency for a given circuit was small, the erection of resonant doublets would have been more satisfactory because of greater efficiency, This would of course have required a means of antenna switching at the transmitters. For the circuits where omni-directional radiation was required, vertical antennas would have been superior. These could have been in the form of wires suspended from catenary strand for the higher frequencies, and topor ULU types for the lower frequ~ncies~ Regardloaded towers or lITII less of the typo used, greater separation should have been maintained between antennas in order to avoid interference due to intermod~ation~ which was a serious problem in some instances. With horizontal or sloping antennas of the type us~d, spacing is restricted by the limited area available for the antenna field* &eater use of vertical radiators would alleviate this problem. (5) Single Sidehd System to Hawaii. ~ilthoughopera- tion of this system was generally satisfactory, improved service would be obtained on the high-grade voice channel by the use of space diversity reception. This would require an additional rhombic antenna and 77 . . M...*. L.L- ---- -&&- L L6-- . -