[ADTech]

1. The PRO is all stainless, that's it. It was extraordinarily expensive to manufacture compared to a stock DB4e and was a one-time only production item. There are no plans to make more as of this time. Its performance parameters are close enough to the stock DB4e that no separate technical data was produced. There is a formal technical data sheet for the DB4e, it's on the website. If you live by the ocean where salt air eats everything, get the PRO. Otherwise, stick with the standard version.

2. I don't see any beamwidth numbers for the C4 or C4V on the website but that thing can be a real potpourri of old and new stuff. Link where you saw it?

For the C4, the calculated UHF BW is ~43° at 470 MHz which narrows with increasing frequency to 31° at 698 MHz. There is no formal data sheet for the C4 (or C4V) although I do have calculated polar plots and a gain vs frequency chart somewhere on my computer at work. I'll see if I can dig them up. Performance of the VHF dipole will be considered to be the same as for the C2V, it's the same module.