I've got the BCD396 scanner radio and now am taking the huge leap of installing an external antenna on the roof. The guy who's doing it suggests a discone antenna. I see several varieties available, from $100 up to $300. I am obviously not transmitting with this unit and will want it for everything from Los Angeles-area police, fire, air and general scanning activity. Which model would you suggest I buy? I've seen the Diamond D3000N, WBD-40 Discone, and the AOR 25-3000 Discone. I'm sure there are others, but what's the best value for the money. It will go on my rooftop of my single-story home. Any advice would be appreciated. Thank you!