Measurement on a BM-63 TV filter

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This hi-pass filter has been designed to protect your TV set from the HF signals transmitted by a nearby HAM station. Let's have a look how it can reject the signals under 45 MHz.

The filter's input and output are connected to the 'DUT' and 'DET' miniVNApro SMA ports. The software used for this measurement is the vna/J from DL2SBA using the 'transmission mode'.

We can notice the insertion loss over 45 MHz is very low. The signals under 30 Mhz are attenuated from 20dB to 80dB.