Test setup

MA1

I made some measurements using my miniVNApro with a simple test fixture fittig the QRP labs lowpass filters.

 

MA2

 

Bandpass filters

I've measured all low-pass filters in the shown test fixture. They show a pretty good attenuation. The first harmonic is suppressed more than 32dBc on all filters.

Keep in mind, that with the current U3s relay board, this suppression is reduced due to some design decisions made by QRP-Labs. Check also the resulting transmitter signal here.

{tab 60m}

 

VNA 170127 152451

{tab 40m}

VNA 170121 084930 VNA 170121 084951

{tab 20m}

VNA 170121 185528 VNA 170121 185452

{tab 6m}

6m

 

{/tabs}

 

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