In 2015 I've build the Frog Sounds QRP transceiver.
This little transceiver still needs improvement:
- The output is still only 400mW
- The key-click is horrible - even with the additional audio cw-filter.
- The suppresion of harmonics is very bad. Check below.
I ran a spectrum scan on my Frog to check for harmonics on the output signal.
The measurement was done using an Siglent SSA3021X and the FA power attenuator.
|1||7.057||Main carrier. Abt. 25dBm what is 300mW|
|2||14.058||1st harmonic. Abt. 19.dBc below carrier. Far too less, I must check this.|
|3||21.060||2nd harmonic. Abt. 40dBc below carrier. This corresponds to the regulatory authorities. But not good.|
|4||28.140||3rd harmonic. Abt. 48dBc below carrier. This is fine.|