I have been testing on the Si4464 Module in the silicon lab EVM board as below.
PN9 signal is good at Max hold in the PN9 mode, but Custom packet Tx is not
I have got higher noise levels of custom packet than those of PN9 packet at Max hold.
I use a RF switch. however , I always set Tx switch to be On and RX switch to be off. Therefore, The RF switch couldn't make worse condition.
I think it causes the SPI operation (e.g. SPI write fifo).
How should I make noise levels in Cusom packet Tx be lowered at maxhold mode in RF spectrum like PN9?
PN9 spectrum as below
Custom spectrum as below
PN9 spectrum at maxhold as below
Custom packet spectrum at maxhold as below
Select Project : PN9 / Custom packet
Center frequency : 262 MHz
Channel spacing: 50KHz
Crystal : Use external TCXO/ Ref Source
I think your situation is described in this article: https://www.silabs.com/community/wireless/proprietary/knowledge-base.entry.html/2017/05/18/ezradiopro_pa_rampi-D5ri
Also a recommended reading is the description of the PA_TC, PA_RAMP_EX, PA_RAMP_DOWN_DELAY properties in the API document at EZRadioPRO API Rev B1B
Note, that digital power sequencing is a new feature of the latest generation Si4x6x. Si4464 does not have this feature.