Hi Elijah,
I assume you have adjusted the potentiometer to get the correct FWD power reading.
Ideally you need to make sure that the pots for FWD and RVS are set correctly (same values) for the SWR calculation to be valid.
I am not sure what the firmware assumes for the resistor division ratio, on the ATU-100 it is 1:3. The thread from Marius implied that this is the value for the ATU-1000 as well.
One point to note is that the maximum ADC input voltage to the PIC should not exceed 4.096V.
If the resistor division ratio is 1:3, then the maximum power is set by the bridge ratio. Estimated maximum power for different bridge ratios are as follows.
1:5? ?Power (RMS) for 4.096V at PIC? ? 38W? ? ? ?<< QRP
1:10?Power (RMS) for 4.096V at PIC? ? 150W? ? ?<< ATU-100
1:20?Power (RMS) for 4.096V at PIC? ? 600W
1:32?Power (RMS) for 4.096V at PIC? ? 1600W? ?<< Marius ATU-1000
This is covered in the ATU-100 manual (see attached)
If the resistor divider ratio is changed from 1:3, the maximum power can be changed, but as such there is no EEPROM variable for this.
I think the bridge ratio could be used to take account of this, but it can only be set to integer resolution.
Example: Bridge ratio = 1:20, Potential divider ratio = 1:4.5, Maximum power = 1400W
EEPROM ratio setting = 20 x 4.5/3 = 30
73, Dave
