DRF1278f transceiver using sx1278.h library. Module loads, but no signal

Hi,

I have a pair of DRF1278f transceivers and am trying to make them work with Arduino (mega).

I used the following as wiring guidance:

And the following sx1278.h library:

I am also using TX and RX codes provided with the library.
Currently it is wired as such:

DRF1278F -- ArduinoMEGA
NSS -- SS ( 53 ) -- with voltage divided to reduce to 3.3V (without 10K resistor)
MOSI -- MOSI ( 51 ) -- with voltage divider to reduce to 3.3V
MISO -- MISO ( 50 ) -- direct (without the 100K resistor)
SCK -- SCK ( 52 ) -- with voltage divider

DIO0 -- INT0 (21, scl) -- direct

Sample codes upload, but produce the following warnings (are they important, what do they mean?):

C:\Users\Mikas\Documents\Arduino\libraries\SX1278/SX1278.h:129:0: warning: "REG_FEI_MSB" redefined [enabled by default]

 #define        REG_FEI_MSB      0x28

 ^

C:\Users\Mikas\Documents\Arduino\libraries\SX1278/SX1278.h:107:0: note: this is the location of the previous definition

 #define        REG_FEI_MSB      0x1D

 ^

C:\Users\Mikas\Documents\Arduino\libraries\SX1278/SX1278.h:133:0: warning: "REG_FEI_LSB" redefined [enabled by default]

 #define        REG_FEI_LSB      0x2A

 ^

C:\Users\Mikas\Documents\Arduino\libraries\SX1278/SX1278.h:109:0: note: this is the location of the previous definition

 #define        REG_FEI_LSB      0x1E

 ^

One uploaded, the DRF1278f seems to be set up successfully! However no data is received:

sx1278 module and Arduino: receiving packets
Setting power ON: SUCCESS 
Setting Mode: SUCCESS 
Setting Header ON: SUCCESS 
Setting Channel: SUCCESS 
Setting CRC ON: SUCCESS 
Setting Power: SUCCESS 
Setting node address: SUCCESS 
sx1278 configured finished

Package received ERROR

I have also looked for other people working with these (or similar) modules:
Another post in arduino forum: http://forum.arduino.cc/index.php?topic=411269.0
Long-distance-DRF1278F-LoRa-Lost-model-tracker
GitHub - matthijskooijman/arduino-lmic: This library is deprecated, see the README for alternatives.

Can anyone please suggest any guidance how to find the problem? I am not familiar with writing/editing libraries and to be honest most of this stuff is dark matter to me.

I dont even know if it is a transmission or reception problem, how could I determine if data is being transmitted?

I will keep investigating, and will post anything useful that I find.

Regards,
Mike

There is a lot of great information at http://www.loratracker.uk/, plus a working, custom Arduino library. Take a look at the dropbox site under the "links" heading.