[coupe pete]

I then disconnected the power and removed the Nano and inspected it. Could not see any issues. I then reconnected it and disconnected it about 5 times and it did not make any difference.  When I pressed the reset button on the nano the "l" LED next to the power LED on the nano flashed briefly.
I then reflashed the nano and it did not seem to make any difference.  
I then replaced it with a new nano and that did not seem to make a difference.
I then checked the voltages on the TX board. The 3.3, 5 and 9V connection points all had the correct voltage. The Battery voltage was 14.4 volts, it was a bright sunny day.
I placed the multimeter on the TX LED and the voltage was pulsing even though i could not see the LED flashing. Not sure if the LED is working ? or if its just nor visible in bright daylight
None of this seemed to help as the receiver is still not getting any data.
Open to suggestions on where to go next ?

I would definitely try the debug mode. This means enabling the debug outputs of the TX unit to the USB port, upload new firmware and watching the output in Arduino IDE monitor... 
 

Code:

// --------------------------------------------------------------------------------------
//   Debug
// --------------------------------------------------------------------------------------
#define ENABLE_DEBUG
#define DEBUG_ID0  
#define DEBUG_ID2  
#define DEBUG_ID3  
#define DEBUG_ID4  
#define DEBUG_ID5  
//#define DEBUG_SLINTERFACE
//#define EASYWEATHER_TEST

If you didn't know what the identifiers 0 to 5 mean, their description is in the Config_Options.h file just a little higher:
 

Code:

// --------------------------------------------------------------------------------------
//   Define which data this unit will send. 0 = Not send this data, 1= Send this data
// --------------------------------------------------------------------------------------
#define ID0  1   // Temp/Hum Data
#define ID1  0   // Not Used
#define ID2  1   // Wind data
#define ID3  1   // Rain data
#define ID4  0   // SolRad / UV data
#define ID5  1   // Hardware Status - System Temp, Battery Voltage etc

And after doing it put the output here, please.

(It is also possible that after a few years of "being outside" the entire PCB will need to be resoldered. It depends on how well prepared it was for the outdoor environment.)

OK. Had a go at this tonight. This is how I configured the debug terms..

#define ENABLE_DEBUG      true
#define DEBUG_ID0         true
#define DEBUG_ID2         true
#define DEBUG_ID3         true
#define DEBUG_ID4         false
#define DEBUG_ID5         true
#define DEBUG_SLINTERFACE true
#define EASYWEATHER_TEST  true

Port was com4. Baud rate was set to 9600 and "no line ending" was chosen.

This was the output - which I assume is rubbish. Is there anything i did wrong ?

Code:

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