What would make the PGXL lose bias current when tuned at only 300 watts? SWR was 1.1.

Larry Blake · April 13

It tuned at 100 watts and when moved to 300 watts it quit transmitting and lost bias current. SWR was 1.1 using Palstar Tuner.

David Decoons, wo2x · April 13

need more info.
What transmitter? How is it connected? What mode are you using to tune and test? Is it possible you tuned SWR with amp in operate?

73

Dave wo2x

Larry Blake · April 13

Using Flex 6600. Tuned SWR with 6600. Placed PGXL in operate mode. Placed in tune and had 100 watts output. SWR is still 1.1. Adjusted to about 300 watts and PGXL quits operating after a few seconds. Still showing 1.1SWR while adjust on PGXL. Using in FT8. AB mode on PGXL.

AA1SS · April 13

Are you saying you tuned the swr with the 6600 tuner. "Tuned SWR with 6600" If so you need to tune after the output of the amplifier.

David Decoons, wo2x · April 14

need details on your configuration. You should never use the radio internal tuner with an amp.

Connection should be radio → amp → tuner → antenna. And tuner must be able to handle legal limit at the native SWR. If you have a 5:1 SWR, a lot of tuners will sedate maximum power handling.

I suggest opening a HelpDesk ticket.

Larry Blake · April 14

Let's try again. Flex 6600, PGXL, Palstar AT2K. Palstar is adjusted for low SWR. Checked with Flex 6600. Minor adjustment to Palstar while Flex 6600 is placed in tune for the lowest SWR on the Flex 6600. After this, the PGXL is placed into Operate. Tune power is applied and set at 100 watts output. Recheck at PGXL, Flex 6600 and Palstar for low SWR. SWR is 1.1 to 1.2. This appears to be a low SWR to me. I've been using tuners for over 50 years. Next while in tune the tune power is raised to about 300 watts. SWR is still stable. After a few seconds, the PGXL quits working. There is no longer any bias current showing on the PGXL on any bands. PGXL boots without showing faults on the front screen. The Flex 6600 with the Palstar AT2K still has a 1.1 SWR. Auto tune is not being used on the Flex 6600. All SWR adjustments are made on the Palstar AT2K. Have been using the Palstar AT2K for over 10 years with a Heathkit SB220. Got the Flex 6600 in February this year. Haven't had any problems with the 6600. Max power is also set to 50 on the Flex 6600.

KD0RC · April 14

Hi Larry, I second Dave's suggestion - submit a help desk ticket.

Larry Blake · April 14

Help desk ticket was submitted Friday evening. Just curious if anyone else has had problems with the PGXL and if I'm overlooking something.

What would make the PGXL lose bias current when tuned at only 300 watts? SWR was 1.1.

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