Need to bury a length of RG6 cable down about 6-8" in sandy soil.Can I use standard cable or is there something special I should use and what is its designation? Is it more expensive? What will happen to standard cable over time if I bury it?
You can bury regular RG6, however the industry recommends against it. UG RG6 is flooded and has a different PVC jacket that resists breakdown and moisture over time. Yes the UG is more expensive and if your situation is for long term, recommended.
I'd factor in how long the run is, how many cables are involved, and so on. If you have to replace it every 5 years, it may not be a big deal to some people. If it only lasts 1 year at a time, that's a different matter.
When I had the BUD most of us were running cables thru PVC. Unless you bury the RG6 deep rodents may have it for lunch. Just get the smallest size PVC and run it thru that. Seal the exposed ends with silicone to keep moisture out.
The corrugated blue tubing (sorry, I forget it's name) is good stuff to use. It's flexible, strong, waterproof, and above all, easy to lay. You can attach standard PVC ends to it - like to terminate it into an outdoor electrical box, or whatever suits your fancy.