I don't wish to sound rude, but being an Extra and hopefully very aware of the RF environment around you, this question should be a no-brainer. I would hesitate to put a log periodic on a consumer grade scanner in an urban-style environment, but that's just me.
Well, this is why I asked the question; to see if others had attempted this. I get varying opinions and I do not live in the heart of the city; I live in the outter county. A directional antenna, such as the LPDA may prove useful, as it can null out weaker traffic in favor of the area I am in interested in, say Orange County.
Will have to give it a try....If it proves to be too overloaded, I could always switch to my Icom R9000....
I would consider something along the lines of the Grove Scanner Beam - less gain than a full sized log periodic, but still has some null ability to it.
Heck, I've even heard of folks turning a TV antenna on its side (to insure receiving in the vertical plane) and using that. Certainly less expensive than a log periodic - and a lot smaller too (depending on the frequencies desired, natch.)