On 7/3/2017 22:37, jeffory broughton wrote:

I am curious what the transmitter power of AO-85 is in either watts or dbm. Thanks.

The PA was characterized over a range of temperatures and battery voltages in its final design, in 2013. Unfortunately, those projected temperatures (-50C to +10C) in the thermal analysis were quite lower than are actually seen on AO-85. FWIW from my best eyeballing of the graphs and given the reset 693 uptime 335876 telemetry (05:51 UTC July 4) with an RX temperature of 41.7C and battery voltage of 3.91, I would guess that the output power could be just under 600 mW. The output power increases with battery voltage but decreases with temperature as the efficiency is lower in warmer temperatures.

800 mW is the maximum output we claim for the launch profiles, about 775 mW was the max measured in this characterization at 4.2V and a temperature of -50C. Given the temperatures we see in orbit (about 10C to 50C), AO-85 probably ranges from about 700 mW during eclipse when it's not in a full sun phase (so cooler overall) at 10C and 4.1V, to 550 mW when it's in a full sun phase (warmer overall) at 50C and 3.8V.

All of that is scientifically based on my possibly debatable extrapolation from the PA characterization data we have on file!

So Paul and John are both right in theory.

Jerry Buxton, NØJY