1. For Receiving and eliminating man made noise, magnetic loop antennas are the way to go. While my Delta Flag modeled better in EZNec, the KY6R Big Mag Loop ran rings around it (bad pun intended).
2. Wellbrook offers a very nice set of different RX preamps, and while my favorite used to be the smaller ALA1530LNP, I can say without hesitation that my 3/4″ copper mag loops, with their 24′ circumference, when fed with a Wellbrook ALA100LN is far and away the best 160/80M RX antenna I’ve ever built. I also can vouch for Andy Ikin as far as the performance of his gear. They do perform and live up to the marketing “hype”. They are very much worth the cost
Some tout the W6LVP Loop as less expensive than the Wellbrook, but I didn’t find that to be true. Plus, I like a solid metal loop much better than a coax loop.
3. The DX Engineering NCC-2 is rediculously expensive, but now that I have used it with such great antennas, I feel my investment is well worth it.
4. I haven’t been able to measure any Common Mode, but should still do more testing
5. Even with just the K3 RX In and no second receiver Dual Diversity, I’m a very happy camper. I need to try dual Diversity at our sunset and listening to several bands. On the BCB I need to listen to KLIB, and on 160, 80 and 40, some CW or SSB
I’ll post later today after trying dual Diversity.