Are the Bridges as the repeater site on the same channel/frequency? If you 2 bridges at each repeater site, connected with a cross over cable, and set to operate at different channels (use 1,6 or 11) and the antenna separated by several feet, you should be able to get full throughput. If you are using identical channels, or channels that with less than 5 channel separation, or have antenna located very close together, this can cause interference between the two bridges, reducing throughput.