I agree, if you can find the right pipe, use it.
Im too lazy, so I use the 1.8" OD pole that was used for my 1000.2, and then slid a 2" OD 24"L pc of exhaust from the auto parts store over it. Bolted in place, it does just fine and the slimline will tighten right up. Cost about $7, have used it twice and has worked very well.
I've been using structual steel tubing for over 30 years, now. I've NEVER seen 1.8 inch actual diameter pipe or conduit in any supplier's inventory. That's NOT even a foreign metric size, since it works out to be 45.8 centimeters.
1-1/4 nominal pipe or conduit is 1.65 actual inches in diameter. That's the size used for the original Dish Network Dish 300/500/1000/1000.2 dishes. It is also the standard size for DirecTV Phase I, II and III dishes.
Schedule 40 is a good option, but it is $40 plus for a 10 foot length at Lowes or Home Depot.
My favorite, however is 1-1/4 nominal IMC made by Allied Tube, which meets rigid conduit specifications.
Intermediate Metal Conduit, IMC - Allied Tube and Conduit - Tyco Electrical and Metal Products
It is as strong as and as deflection resistant as rigid schedule 40, at ablut half the weight. It is made of a specially formed heat treated steel. It has both a special galvanized coating and an organic clear coat. The NEC, IEC and UL are very strict on corrosion resistance, which is less so in ASTM specs for pipe used in plumbing.
I can get a 10 foot section at my local Ace Hardware Store for $20.
Along with my colleague's adapter that he sells on eBay;
DirecTV AT9/AU9 KA/KU Adapter for old 1-5/8" pole - eBay (item 150277109969 end time Aug-05-08 21:23:38 PDT)
With the adapter, the IMC conduit and a clear line of sight to the satellites, you are covered for almost any future satellite need. If you switch to Dish, you're covered by just removing the adapter with the AU9 slimline dish.
My dealers and independent installers really like this setup, because we need to carry only one type of pole for both DirecTV and Dish.h