Looking for a website that gives comparative performance of diodes (max
frequency for UHF use)

I don't know of a broad-spectrum site (i.e. one which is multivendor)
other than general datasheet-search sites such as datasheetarchive.com

One good place to start looking would be at www.avagotech.com - I
believe that Avago Technologies is the current inheritor of the line
of RF Schottky diodes originally made by HP and then by Agilent. Some
of these parts are useful up to quite a few GHz.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!