Measurement of the signal quality of QRP-Labs U3s with low-pass filters.Transmitter output is fed into a homemade 40dB power pad. The spectrum is measured using an SIGLENT SSA3021X analyzer.
The bias voltage was about 2.6VDC and the PA voltage was abt. 7VDC.

{tab 60m}

60m 60m 10kHz 60m 100kHz

{tab 40m}

40m  40m 10kHz  40m 100kHz 40m 1MHz

{tab 30m}

30m  30m 10kHz  30m 100kHz 30m 1MHz

{tab 20m}

20m 20m 10kHz20m 100kHz 20m 1MHz

{tab 6m}

6m  6m 10kHz   6m 100kHz 6m 1MHz


2014 CW (Morse Telegraphy) was added to the German Nationwide Inventory of Intangible Cultural Heritage.