I have noticed that many amplifiers are designed to be most efficient
_NOT_ at room temperatures, but a bit above room temp. A good compromise
in design. I have noticed this is both tube and solid state amps. I do
not have your amplifier in front of me, rather I am speaking in general.
73, Bruce, W8HW
=========================================
On 10/16/2021 10:32 AM, Pete Smith N4ZR wrote:
FWIW, I see something very similar in my KPA-1500. I had assumed it
was software protecting the transistors, just in case.
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at<http://beta.reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.
On 10/16/2021 10:05 AM, Steve London wrote:
I have a Commander HF-2500 Magnum, with a pair of 3CPX800's. Great
amp.
It has one quirk, and only on 15 meters. If the amp has been dormant
for a
while, the output power is initially low: about 1100 watts. Key down it
gradually rises up to 1500 watts over about 10 seconds. After that, if I
intermittently transmit, at least every 5 minutes, it will stay at 1500
watts. Only after being idle for ~30 minutes will it go back to the low
output state.
My thought is that something in the input pi network is heating up.
However, I have accurate SWR/power meters on both the amp input and amp
output. Neither the input power nor SWR is changing as the output power
rises. As the power rises, the grid current drops, but the plate
current is
unchanged. Again, this is only on 15 meters.
Suggestions ?
73,
Steve, N2IC
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