On Feb 8, 2020, at 1:48 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

?Absolute maximum power spec into a SAW filter is typically 5dBm.
We definitely don't want the RX Si4432 to drive it with 20dBm
when operating in the "P6 3" signal generator mode.
So Jan 17 tinySA.ino code could destroy level 7 diode ring mixers and?
most SAW filters.

Jerry, KE7ER



On Sat, Feb 8, 2020 at 01:27 PM, Jerry Gaffke wrote:

The command "P6 3" of tinySA.ino appears to set both Si4432's in transmit mode
for use as a signal generator.? In this case, I'd expect the LO to be at 7dBm
and the signal out of what is normally the RX Si4432 to be about 10dB below that.
So the 3 LSB's of reg 0x63 should be at "011" for 8dBm as above, and at 000 for a
minimum power level of -1dBm for the RX Si4432.? However, command "P6 3"?
appears to put them both at maximum power of 20dBm, which may work if it doesn't
blow away the diode ring mixer, and will certainly emit a large signal.
However, the output from the mixer will be a square wave instead of a sine wave,
and thus have far stronger odd harmonics going into the 250mhz LPF filter.
The comment "Set low power" at line 1866 is incorrect, as is "Both on RX' at line 1863.