Hi Felix,
Thanks for your comment, the units are similar with the first experiences I made with RFM69, the transceivers are soldered in a breakout board, connected by jumper wires to ATMEGA boards. I currently don't have other RFM95W nodes, and rotating the ones I have I get similar results. These were just some quick tests, I have some situations where a bit extra range could be extremely useful (I have to use nodes as repeaters in some situations when I use RFM69 radios), so this was just a simple first evaluation of the RFM95W radio. After your message I've added a ground plane below the radio/antenna (and a decoupling capacitor on the RFM95W power supply pins), the results are now better, but the RSSI is still lower when compared with the RFM69 (and the RFM69 don't have the ground plane below the 1/4 wave monopole). But for the RFM95 it had a positive impact, now I have about -38 / -40 dBm in nodes close, and in the same scenario I had -100dBm now I'm reading -73dBm, so the antenna ground plane / decoupling capacitor on the radio power supply did have a very positive impact on the RSSI level, all the rest being equal.
But I think that the RSSI difference could also be related to the different technologies and radio configuration used, this was the reason for my question in the first place, is it expected or not that the RSSI level would be different when using RFM95 versus RFM69, both at 20dBm output power?
I've noticed some posts referred to the use of the maximum output power at 20dBm and others at 23dBm (setTxPower), besides the legal aspects, is the RFM95 really capable of generating 23dBm? I've only saw 20dBm on its datasheet.
Best regards
Fernando