This might be the strangest behavior of this amp I have heard of so far. I have a 257' EF wire with a 9 to 1 UNUN (grounded). My HF-AUTO tuner shows SWR 1.08 for example. Only in SSB as soon as I begin to talk the amp trips off with the SWR. I'm watching the SWR on the tuner, its not budging but on the amp it is jumping all over until it bypasses. Driving the amp with only 10 watts causes this to happen and I have tried it with my 7610, 7300, and 991A. Now what I'm not understanding is this. This behavior occurs only when I use a 75' run of LMR 400 coax. I have even tried a different piece of 75' LMR 400 and the result is the same. If I use a 150' run of LMR 240 the amp doesn't trip at all. I have replaced all the jumpers between the components to eliminate them as the cause. Same result. I can tune this same wire for 80M and the amp works fine regardless of the coax feed. Any thoughts?
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73,
Jerry
Jerry Raia