Cant help you on the comparison, Ive had this one up for 3 years and its been a good antenna for me, took some hard weather and a tree branch a few times, the only thing that has happened is a small element got broke off and I got replacements thru my local RS all eight for like 10 bucks or so. Im sure someone can help answer your question............Hoser
Diamond antennas use much better materials in the construction and very rarely have elements that break off like the radio shack discone. As far as reception, they are pretty much equal and as always stated use high quality coax. Coax will kill reception no matter what antenna you use, LMR 400 is my choice coax.
I have the RS Discone as well. I am very happy with it.
When I wanted to purchase an outdoor antenna, it came down to either ordering something online, paying for shipping, and waiting for it to arrive - or just drive a mile away and bring it back home with me. I already had the mast, coax and other hardware; so I was anxious to get it installed.
I've not had "hands on" with the Diamond unit, but I have no doubt it is more rugged. Functionally the specs are the same.
My RadioShack discone would drop an element if you even looked at it funny---The thing was wasted after just one winter and spring in Central IL. My Diamond is MUCH more rugged, it has been up 5 years now, no sweat. I would only recommend the RadShack for indoor use.