Re: KPA 1500 ATU Issue

Bob McGraw - K4TAX

A systematic approach is to start at 100 watts using the amplifier and ATU. Allow the ATU to resolve a match and note the SWR value.  Then start increasing the drive from the transceiver in increments such as to attain 200 watts, 300 watts, 400 watts, and etc.   At some point, it would seem from prior descriptions, something in the antenna system is failing thus causing the SWR to increase.    Always question; connectors, jumpers, feed-line, balun, antenna traps.   

Further, using a known good 50-ohm dummy load, allow the ATU to resolve a match into the load.  Do this on each band.   This is necessary to prove the ATU integrity.  Do the same power increment tests again.  If nothing fails, then it is most likely in the components of the antenna system.   If it should fail using the dummy load, then one can suspect a component breakdown in the ATU. 

Bob, K4TAX

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