Very good Bob, sounds great.
73 Chris
On Sat, May 18, 2024, 10:43 Bob Stricklin via pacsat-dev < pacsat-dev@amsat.org> wrote:
I have the ability to make the power out of the AX5043 what I want it to be thanks to the good suggestions.
When I turn it up to max power I am seeing 0 dBm into the PA. At this point the PA has 5 dBm out. To get to 2W we need 33 dBm to be at 2W however we the amp would need to be higher by about 1 or 2 dBm to overcome the loss of the final filter. I do have the PA held back by limiting its current and only applying 5V and this time. I want to see the input side working properly before turning this up. I also want to change the code to allow the 5V be turned on only when there is a need to send packets. Otherwise, the PA continues to draw idle current and even though the voltage drop is low there can be some heating. Eventually we will need to look at the duty cycle of the PA and may need to plan on some sort of heat sink/spreader which gets complicated on a satellite.
I am changing the LEDs to have one LED blink with a heart beat and one each for TX and RX activity.
There is no oscillations on PA at this point and the second harmonic is not showing up past the filter at all. This is good news.
Supply current goes up from 260 mA to about 360 mA when PA is active. This will increase when we get more PA power output.
I am working on the code to do power control and operate the LED. I have one LED operating now and I see where to turn on TX LED. Bot TX and RX LEDs can be controlled as part of the interrupt routines coming from the AX5043 I believe.
Bob
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