Hello:

Will probably try a coax feed, and a Balun, to the random length wire
running around the four sides of
my attic to reduce noise, hopefully. Do listening only, up to 30 MHz.

a. For a receiving 9:1 Balun (coax to a random length wire in attic),
does the Balun have to be grounded ?

Or, is it grounded "adequately" via the coax - to the radio chassis -
to an earth ground from the radio chassis ?

[If the Balun Does require a ground (also), wouldn't this possibly
cause a ground loop in that it would be grounded at both ends ?]

b. Anyone have any experience with, or opinions on:

-the 9:1 Balun by RF Systems in the Netherlands
(termed a magnetic balun, how it's different from a normal toroidal
transformer coupling, I have no idea ?)

-or the unit by Win Radio (WiNRADiO WR-LWA-0130 Long Wire Antenna Adapter
$39.95 ADP35)

c. Any significant difference in the type of coax used for listening only,
with a run of about 50 feet.
Used LMR 400 for my attic scanner, but would like to avoid the hassle
of stringing the large diameter coax again, and possibly
just use a small diameter coax. Would one likely notice any difference
up to 30 MHz ?

Thanks,
Bob