FBinNY 

What I said still holds true. Unless you're dealing with an extremely rigid rim with a relatively deep profile, or one with a pronounced flattened zone, odds are that it's not the rim, it's you.

Most radial hop is introduced early on by tightening spokes unevenly, and is VERY difficult to resolve once the spokes have significant tension. The key to dealing with hop is not to introduce it in the first place.

Before spending dough try this the following (worst case, you'll waste some time, but learn something in the process.

1- loosen this wheel to fully slacked spokes.
2- decide on a gauge for in initial spoke turns. You can use a screwdriver with a pin that pushes it out at a certain spoke depth, or simply put a thumb nail on the last thread, and bring all the nipples to that.
3- add 2 full turns to all right side spokes, if that doesn't cause meaningful tension (otherwise tighten right, loosen left to establish the 2 turn differential. That's will establish approximate dish early on.
4- working by degrees turning all nipples the same amount. ie. half turns all the way around, and repeating, until the wheel is at roughly 1/2 the desired final tension.
5- do a first rough alignment (don't obsess because it'll change, but get the wobble within reason, say 5mm TIR. (total wobble)
6- using only right spokes align focusing 90% on hop, and get overall roundness to within 1-2mm TIR. This is critical because it's easy to final true for wobble, but not for hop
7- check dish, and dial that in. I usually work either all right or all left based on the tension so far.
8- you should have a reasonably true wheel at mid-high tension. Align it as you would, again close, but not obsessive.
9- add tension, keeping in mind that the left spokes exert more sideways pull than the right, so it's like 1/2 turn on all right spokes, then 1/4 turn on all left. Recheck alignment and dish
10- as you get close (say 80-90% tension goal) tighten tighten ONLY right spokes, so that you end up with a slightly over dished wheel, and true close to final specs (<1mm hop, <2mm wobble)
11- add final tension with left spokes, while bring dish back home. This is a bit of a touch thing. I generally can hit my target tension during this step, and barely have to touch the tighter right spokes again.
12- final true for wobble and hop, keeping in mind that right spokes have greater effect on hop, and left on wobble.

Whether or not this will work with this rim is unknown, but the practice, and understanding how the process works will serve you well on all future builds.