Can I use just two external antennas with the E3000, or do I need all four since it's a MIMO 4x4 router? I'm checking our this one but it's a little expensive: sohoboost.com/products/wideant4-plus-5g%E2%84%A2-for-cradlepoint-e300-c18-true-mimo-4x4-quad-antenna-set-ultra-high-gain-5g-nr-sub-6-with-4g-and-3g-fallback
