Seems to be a bit expensive at $250. They say it covers from 25MHz but specification says swr are an incredible 41:1 at 25MHz and drops to 2:1 only at 88MHz. There must be much more cost effective discones than this one?
Are you planning to do transmitting with the antenna? If not then SWR really isn't a factor in the reception aspects - I mean it is, but for receiving purposes SWR is rarely a serious consideration in choosing an antenna for monitoring duties.