Do you need the cameras to be genlocked, or do you just need matching time code?
If you just need timecode, I'd skip the sync altogether and just run timecode.
If you need genlock (if you're feeding a production switcher, say), I would highly recommend using a proper sync generator and distribution amp to feed good sync to the cameras - bad sync can really ruin your day (by ruining your recordings).
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Jesse Rosen
Director of Technical Development
Abel Cine Tech, Inc.www.bustedskull.com