I would like to discuss some topics about Tx power regarding the E32 modules from Ebyte.
The first topic is about the maximum transmission power (dBm). Ebyte claims that some models (e.g.: E32-915T30S, E32-868T30S) have Tx power of 30 dBm (1W). The problem is that Semtech’s SX1276, using PA_BOOST, has a maximum of 20 dBm at Tx power (and is limited to 1% duty cycle). How Ebyte can deliver 10 dBm more than the max available from SX1276 ? I understand that 20 dBm would be the max possible power, and with restrictions on operation.
In E32-915T20D user manual, they present this table of parameter setting
It shows that 20 dBm is the default option, implying that this power can be used with no limitations in regular operation.
This leads me to the second question… Is it right? Can I used 20 dBm of Tx power freely?
In this same table, it shows a minimum power of 10 dBm. On the other hand, SX1276 manual shows a minimum of 2 dBm using PA_BOOST. Why Ebyte limits it to min of 10 dBm?
If we read E32-868T20D manual (apparently a module with 20 dBm max Tx power), it shows the following table
I am pretty sure it’s a typo… For this module (as it is a 20 dBm max), the table should be like the one shown in E32-915T20D manual.
Nonetheless, for modules sold as 1W power (e.g.: E32-915T30S, E32-868T30S), this table should be right. This leads to the first question… How is it possible to deliver 30 dBm Tx power?