I have been researching how metals affect radio transmission but have not found anything conclusive to the specific scope about planet density if it is mostly metal.
One of the posts that I found any info on was this page http://www.madsci.org/posts/archives/2002-03/1015162213.Eg.r.html
I have also found that gravity does affect wireless radio transmission. http://www.dslreports.com/forum/r13178764-Are-wireless-transmissions-affected-by-gravity-
But what would it take to entirely prevent transmissions in our current radio systems used by our space travel agencies, and what modifications would need to be made to prevent such losses in transmission should we encounter such a situation?
Background (what prompted me to ask)
I had a dream that i piloted a small craft to a comet to mine for metal. But its magnetism disrupted our radio communication. So I am wondering if this could really be the case.