We study the tradeoff between energy and bandwidth efficiency for short packet-transmission systems for wireless sensor networks. Using random coding bound (RCB) analysis, we show that 16-ary and 32-ary orthogonal modulation schemes provide reasonable balance between energy and bandwidth efficiency. In addition, we compare various channel-coding schemes and conclude that convolutional codes are well suited for wireless sensor network applications having excellent performance and reasonable robustness to imperfections, such as estimation errors.