Drain current when not transmitting

Steve London

Looks like my PGXL has a problem. I'm seeing 2-4 amps of drain current, and temperature of 52 C when in operate, but not transmitting.

Can others confirm that this is not normal ?

73,

Steve, N2IC

David Decoons, wo2x

The bias is 2 amps in AB mode (CW, FT8 when MEffA is on). 4 amps in AAB mode (SSB).

The bias will stay on for about two minutes after last transmission so the power supply is ready when transmit. After 2 minutes the bias should go to zero.

Dave wo2x

Steve London

Thanks. Yes 2/CW, 4/SSB here. I did some more tests, and learned this about my amp:

• With the fan set to Standard Mode, it behaves like you say, with the current going to 0 after a few minutes.
• With the fan set to Contest Mode, the current stays at 2/4 amps, never going to 0.

I suspect this is by design. FW 3.7.32.

73,

Steve, N2IC

David Decoons, wo2x

Yes, forgot about contest and broadcast leaving the current on. I run mine in standard mode 99% of the time. Then again, it is in a server cabinet in my garage.

73 Dave wo2x

Steve London

Used the PGXL on 160 for the first time. In mode AB, CW, the idle current is 4 amps, instead of 2 amps. Same thing on 6 meters. Firmware bug ?

73,

Steve, N2IC

Mike-VA3MW

@Steve London

No, I am pretty sure that is normal and by design. I can't find the notes from the Developer but it rings a bell.

73

David Decoons, wo2x

Yes. It is designed to use 4 amps bias (AAB) on all modes on 6 and 160.

Dave wo2x

Steve London

4 amps , even with the fan running in Contest mode, means that the PA heatsink stays at 53.5 degrees all the time, even when not transmitting. That seems hot. Hope it survives 48 hours in CQWW SSB at the end of the month.

Mike-VA3MW

I stay in contest mode 100% of the time at my remote station.

In the winter, I leave my PGXL in Contest mode/Operate for 2 months straight to provide heating for the 'box' all the equipment is operating in at my remote.

I have done this since the PGXL was released without issue.

If you are concerned, just move back to Standard mode and the sensors in the PGXL will take care of all the required cooling without issue.

Don't worry, the designers take all of this into consideration from day 1. After all, they are ham operators like us but with a lot more education and experience.

So, please don't worry—your PGXL is designed to handle the demands of contest mode and will continue to provide reliable performance.

73