Peter, Can you test into a dummy load, and if so what are your results? Preferably with all existing switches, coax, etc out of the path between rig and dummy load. Just trying to isolate between coax, switch, antenna system issues and rig issue first.
On the surface it sounds like a rig issue, and maybe one final tube is not getting drive, or is offline somehow. But let's make sure it is the rig that has the issue first. 73, Ron WD8SBB --- On Sun, 2/5/12, Peter Ravn <fas...@privat.dk> wrote: From: Peter Ravn <fas...@privat.dk> Subject: [Drakelist] T4XB tune and load problem To: Drakelist@zerobeat.net Date: Sunday, February 5, 2012, 7:03 AM Although I strictly follow the tuning procedure described in section B on p. 14 in the instruction manual, my T4XB has suddenly changed behavoiur. The output power on all bands has gone down from on average of 100 watts to 45 watts. The AC-4 bias reads .07 on the plate meter when the gain is fully CCW, and the mode switch is on TUNE. With the GAIN at app. 9 o'clock, the reading is 0.15 A, and with the PLATE control the plate current is dipped - more distinctly on some bands than others. Increasing the GAIN to maximum the reading is 0.2 A. Alternately adjusting the PLATE and LOAD controls for maximum RF output, the result is 45 Watts. As before SWR is low, so apparently the T4XB is able to tune the antenna. But the LOADING control on 80 meters has to be turned fully CCW to achieve the best result, whereas it before was between 3 and 4, which might indicate that the tuner doesn't work as it should. Add to that the finals get hotter than before. So there must be a mismatch. The question is where? 73 de Peter OZ8CTH -----Inline Attachment Follows----- _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
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