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A600 PA : Some measurements. 
 (20210404) 20210502

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Cooling profile temperatures.
measured near the FETs.
3.65 MHz, 1Wp drive, 100% noise modulation.
Max allowable cooling profile temp = 68C.
Tamb = 24C.

Mode Test output at least 2 min. with : Temp [C]
  2x0.9Adc bias,
no drive.
(1.82A@48Vdc)
8C above Tamb.
AM 125W carrier 50
FM 200W continues 57
SSB 400W peak 47

REM:
If "Pure Signal" technology is used, the FET bias currents could be reduced to 2x 0.2Adc, lowering these temperature rises by abt. 9C.

Drive and output.
Loaded supply voltage 48V.
PA drive is max. 1Wp with a 100W -20dB attenuator between TX and PA input.
Output, Ib and drive noted as indicated by the moving coil meters.

LPF [MHz] 1.8 3.5 7 14 14 28 21 50 30
Tested band [MHz] 1.8 3.5 7 10 14 18 21 25 29

TS570D output setting [W]
70 60 85 85 100 100 100 100 100
Po [W] 400 400 400 400 350 400 350 380 400
Ib 14.5 13 14.5 13 14.5 13.5 12.5 12 11
Gate drive Vpp [V]
(PA gate drive indicator)
(Max. safe value is 12Vpp).
5 4 6 6 6+ 6+ 6+ 6 6

 

After measuring the temperature differences between the plastic top side of the FETs, and the cooling profile, the calculated absolute max cooling block temp for a chip temperature of 150C, and long FET life, is in my PA : 68C .