Stefan DK7FC is doing very interesting test using WSPR with QRP TX on MF.

 

So this evening, I’ll also be testing a very very low power configuration :

 

• 25 milli W output TX power (1 W and a 16 dB serial PI resistors attenuator on 50 Ohms) ;
• 25 meters tube vertical without top hat capacitance antenna ;
• The PAR (apparent radiated power) is about 200 microwatt.
• I just mesured with oscilloscope the RMS HF voltage at the base of the antenna (at cold end of the serial tuned coil). It is only 0.7 Volt !

 

Of course, I think nobody can decode this low power signal on day time. I wait for some WSPR reports to night...

 

73. Andy – F6CNI – JN19QB