One of the limitations of filters made using quarter-wave open-circuit stubs (at the frequency to be rejected) is that this circuit will also reject odd harmonics of the rejection frequency. This is because a line which is an odd number of quarter-waves long behaves like a quarter-wave line. If you want to make a filter that will reject 144MHz using open-circuit quarter-wave stubs, their three-quarter-wavelength resonance will also reject 432MHz. Likewise you would have similar problems with 50 and 144MHz.
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