Many thanks to SWLing Post contributor, Rolf, who writes:
I made a great discovery tuning using a second passive analog radio.
When I tune to Radio Caroline, for example, on my portable I can receive the signal okay. When I put the receiving radio on minimum then place it next to and couple it with the second radio, it is receiving a lot better!
Even stations I could hardly hear, now i can hear them!
Check out my short demonstration video:
That is fascinating, Rolf. Thank you for sharing. Indeed, this is one of the reasons why I try to maintain a good distance between radios when comparing them in reviews. In this case, though, you’re using coupling to your advantage!