On Sat, Jul 8, 2023 at 03:47 PM, Dave, N1AI wrote:
My sbitxv2 arrived with a paper giving calibration results.
Are the results being kept in this file on the sdcard so that the software can access them?
I'm wondering because I don't want the settings to be lost if the sdcard is corrupted.
To answer my own question, I finally compared the numbers on the paperwork in the box the sbitx came in to the ones in this file, and they are not the same.
According to the factory test procedure described on sbitx.net, the numbers on the sheet are the peak voltage produced by the radio on each band when set to drive level 100, as measured by an oscilloscope placed across a 50 ohm dummy load.?
The scale numbers in hw_settings.ini file are the values used to set the internal gain used on each band, sbitx.net describes how they are found.
The power amplifier gain decreases from 3.5 MHz to 30 MHz. The gain is compensated by decreasing the drive on lower frequencies and increasing it on the higher frequencies. These settings are in the file /home/pi/sbitx/data/hw_settings.ini. In almost all cases, these settings will work for you.
If you would want to recalibrate the drive for each band, this is how it can be done:
The sbitx can automatically run this calibration. Before you do that, you need
- The sbitx power meter must be calibrated as described above
- Attach a dummy load (not an antenna)
Start the sbitx, from the left panel, choose console. In the edit window of console, type?txcal?and press Enter. The software will trudge along for a minute or so and complete the calibration process.
As mentioned earlier, the best thing to do is keep backups of the sd card so you always have the factory set of data somewhere.
If the file goes missing the software opens and reads default_hw_settings.ini which contains a conservative set of scale values which means you can still transmit but won't produce as much power as you would with the factory settings.
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Regards,
Dave, N1AI
Dave, N1AI