Interesting question with unusual results. My edge of reception has an SNR of -14 dB with my lock coming and going. When I put the cone on the LNB at that point and aim it along the LNB’s direct axis to the sky, I get no change in SNR or Lock/Unlock status. But if I turn the cone in the direction of the satellite in the sky without moving the LNB, I get constant Lock and my SNR shoots up to - 9.5 to -10 dB.
I also got the same results today with the LNB pointed correctly. Without the cone, my SNRs were in -12 dB range with constant lock. With the cone over the LNB, pointing to the satellite, my SNRs went up to the -8.5 to - 9.5 dB range. What I did notice today (which I wasn’t looking for in my first test), was with correct LNB orientation, I could get the SNR to go into the -7.5 dB range by just sweeping the cone a bit in the general direction of the satellite.
Are we talking wave guide here, or still noise reduction? Ken