I just got an PM from the SL member I bought the CB radio from. He used BRP headsets from the get go. He had no problems with it. Two of his buddies had squeal problems with their CB/intercom that were solved by switching to BRP headsets. I have seen other comments here that indicate BRP headsets were the solution to the squeal.

Can anyone tell me what physically is different about the BRP headsets vs the others?

As much as we may not like the idea of being locked into a specific system to make the CB work, that may be the best solution. I really like the sound quality I get with my Edsets headset. I put four ferrite chokes on the lower cable and that seems to have pretty well squelched the squeal, but the use of ferrite chokes on the headset cord is not good due to their weight.

However, I still believe a big cause of the problem with the BRP CB is an insufficient ground plane and the BRP headsets can do nothing about that. The lack of ground plane can and will manifest itself in a shorter transmission range.