PGXL and efficiency

Ignacy

I use Expert 1.3k-fa and I am thinking of upgrading to PGXL. The reasons would be 1) full integration with SmartSDR and 2) full SO2R, and 3) higher duty cycle.

The materials for PGXL seem to promise 1500W with SWR up to 2:1. This means providing full power at both 25 and 100 Ohms. To provide 1500W at 100 or 25 Ohms, the amp must be capable of 3000W at 50 Ohm. Then with perfect SWR it would be inefficient at 1500W, with lots of heating. Reports of loud fan at full load seem to indicate lots of heat dissipation

So a question is whether PGXL provides 1500W at SWR of up to 2:1, as measured with power meter that compensates for higher SWR, or the output power with SWR of 2:1 is less and the amp just does not shut off.

I run 1.3k with antenna tuner. Minimal heating.

Ignacy, NO9E

Mark_WS7M

Hi Ignacy,

I am sorry but I can't answer your direct question.

I will say however that I'm not sure running 2:1 is a great idea at high power. Lots of things tend to heat up. But I am just speaking from my basic experience, I have not tried running the PXGL in that condition.

I have run my PGXL on FT8 into 1.5:1, 1500 watts continuous and the amp doesn't breathe hard. I do notice the harmonic load temp going up some but it cools very quickly.

I have an SPE 2K FA that I bought the PGXL to replace and while the 2K FA is a truly great amp, it cannot sustain 1500 watts continuous duty cycle. It derates to like 1100 and I could not find a way to force it, even with extra cooling to stay there.

Granted the difference between 1100 and 1500 to a remote receiver is probably very little, it was more of a concern on my part that the amp have the headroom to support high power.

Until winter is over and it's a little warmer, my PGXL is in my shop which gets blasted by my main house heater. It's probably 80 degrees F in the shop at all times. Even with this somewhat higher ambient temp the PGXL cools very quickly. When I can move it to the desired location in my HVAC room, the ambient temp in there is usually around 65. I expect to see the amp stay even cooler.

I'd be curious to know if you end up going with the PGXL and how it does on the 2:1 SWR.

Mark_WS7M

Hi Ignacy,

I am sorry but I can't answer your direct question.

I will say however that I'm not sure running 2:1 is a great idea at high power. Lots of things tend to heat up. But I am just speaking from my basic experience, I have not tried running the PXGL in that condition.

I have run my PGXL on FT8 into 1.5:1, 1500 watts continuous and the amp doesn't breathe hard. I do notice the harmonic load temp going up some but it cools very quickly.

I have an SPE 2K FA that I bought the PGXL to replace and while the 2K FA is a truly great amp, it cannot sustain 1500 watts continuous duty cycle. It derates to like 1100 and I could not find a way to force it, even with extra cooling to stay there.

Granted the difference between 1100 and 1500 to a remote receiver is probably very little, it was more of a concern on my part that the amp have the headroom to support high power.

Until winter is over and it's a little warmer, my PGXL is in my shop which gets blasted by my main house heater. It's probably 80 degrees F in the shop at all times. Even with this somewhat higher ambient temp the PGXL cools very quickly. When I can move it to the desired location in my HVAC room, the ambient temp in there is usually around 65. I expect to see the amp stay even cooler.

I'd be curious to know if you end up going with the PGXL and how it does on the 2:1 SWR.