Hi Jeff,
I did a check on the can with the original stub, it had a broad notch at 238 MHz (in addition to the tunable smaller notch at the 154 mhz). Looking at the Spec analyz with the trk gen, it looks like the starting level is 0 dB, then drops as the notch appears, then comes back, but this higher freq side doesn't come up as fast (hence the degraded attenuation). Does the application of the stub (evidently cut for some x amount higher frequency than the notch) actually pull this side up, giving less attenuation? Do you know what the formula would be for cutting this stub? I didn't check the return loss.... it was obvious that there was a problem! Thanks, Tim W5FN
