BobS wrote:
I live on the 2nd floor of a condo (no outside antennas allowed) with a
random wire (60') from my R8B, out the window, and thrown over a tree
branch. No separate feedline; just one length of thin wire from radio to
tree. As expected reception is compromised with excessive noise. Can
anyone advise if there is a way to reduce the noise? *Can't have a
ground rod.


You first need to identify the noise source. Could be power line
arcing due to a bad insulator, or a neon sign, or whatever.

What does the noise sound like? Just a steady buzzing sound or
something else? Does it cover the whole shortwave spectrum or just a
certain range? Better/worse in rainy weather? Try to find a pattern
based on time, weather, etc.

If the antenna is near the source of the noise, you might be better
off with a smaller antenna further from the noise source. Experiment!

Art, N2AH