The amps with 30 down test ports are resistive you can sweep the return through it but it may look choppy. You can use a tap on the LE or there may be a testport on the return card if it says IP it's an injection port if it says TP its a test port. There are several generations of mods the newer style has 20 down TP's and set up nice. Watch your output levels on the tna's it's easy to set the trunk outputs up to normal spec's and ports 3/4 will be smoking. Scott
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