I would suggest doing some googling using "Shaw satellite footprint coverage in USA" and you'll find lots of good info. Can also find tech. info. on dishes, LNBs, and how to aim. I've been learning a lot about satellite TV for RV-ing lately and maybe you can find something helpful below (sorry for being long-ish :)). I haven't been able to find a single good website for all the info. you'll want and have had to get snippets of it here and there.
We're on Bell satellite TV at home and they use two satellites (Nimiq 82 & 91). We've been using a spare receiver from home and have been able to get a strong signal as far south as the WA/OR border so far using a 24" dish. A larger dish will have more gain (capture a stronger signal) and may help the farther south you go. I recently bought a 33" dish to try out but will have to wait until next season now. Bell re-jigged their coverage footprint a few years ago and supposedly you can't get reception very far south into the US. But I have read about some people being able to get reception into the southern states. Dish size, LNB type and your ability to accurately align the dish are important in capturing a weaker signal.
Bell HD channels are mostly on sat 82 so have been using a dish with only one LNB. Have not been able to get the programm schedule beyond an hour out and only just discovered that the full schedule is on sat 91, pffft... Using 2 LNBs means you have to set the dish up for skew which will take even more time. Using one LNB only is much easier.
I don't know anything about Shaw's satellites but it appears that their satellites have also been re-jigged to cut off closer to Canada as of 2012 as mentioned
here. Don't know if just one LNB will work on Shaw service?
Accurately aiming a dish is important, especially for Canadian satellites that have the signal drop off closer to the Can/US border. There are simple and low cost "satellite finders" like the one Winegard has. These have a tone signal that changes in pitch as you sweep your dish left/right & up/down (azimuth & elevation). I've found that it can be a slow process sometimes fiddling with it to peak a signal. Your receiver will have a dish pointer menu that will tell you what satellite you are locked onto and what the signal strength is. Takes some practice at first to get it all going in a reasonable amount of time when you're travelling between CGs a lot.
Getting a clear shot at sats is extremely important and you can't have trees or structures blocking the signal. Sometimes it takes some creative placement of a dish (or your RV if a rooftop one). Have seen a few folks reel out a couple hundred feet of coax. Trees probably not a problem in Arizona like up here... Sometimes a lot of time & patience is needed to get the dish aimed right. Sometimes I can plunk it down and have a good signal in seconds. Some CGs have a "satellite row" without trees but sometimes are all taken when you arrive. But, if using Bell or Shaw, sometimes you can find an opening between trees that won't work for Dish or DirecTV. Once in a while you just have to settle for a DVD or book.
😞I recently bought a Birdog sat meter (used on ebay for under $100 USD). Turns out that while these are excellent for showing you exactly what the signal strength is (graphic display) and when you are locked onto a sat, it can't tell the difference between sat 82 & 91. Means more time & effort to figure out exactly what sats you are aimed at. Don't know if Birdog has the same issue with Shaw sats.
If you will have a laptop and a mifi hotspot (we use Verizon), dishpointer.com will give you azimuth, elevation & skew for your exact location. If you have an iphone, there is an excellent dishpointer app and you can point your phone into the sky and it will show you the sats you are looking for and if there are trees or obstructions in the way.
We do all of our camping in the US and use our sat setup a lot. We see lots of people in CGs with Shaw & Bell dishes south of the border in Wa. Maybe you haven't figured out how to accurately aim the dish yet? Have you tested the setup at home first to make sure the receiver, LNB, interior cabling, etc. is okay? I would hazard a guess that you need to abandon any factory installed sat coax and run all new. I was able to run new coax from the outside jack up to the receiver and then HDMI cable from receiver all totally concealed in the cabinetry, walls & ceiling. Luckily we have an arched ceiling and there was a perfect spot above the kitchen cabinets for the receiver.
I don't know what channels you get on Shaw but on Bell, we have a couple thousand and there's only a handful that are worth watching. Annoying! There's many shows and channels I'd like to get but would cost a lot more for a bundle upgrade. If we ever get Bell fibre optic service in our rural area, we'd dump Bell sat TV for home & RV-ing.
Having said all this, a couple of days ago I had an in-person chat with a tech at a commercial communications equip. supplier. He knew all about the Birdog meter issue I was having as he has done programming for it. In the end, he said trying to use Can. sat service very far into the US is a waste of time and you are much better off using DirectTV. They also have a pay-as-you-go plan which is great for RV-ers.
Have read that many CGs now have digital cable TV and can be an alternative sometimes. Used it in one CG on the OR coast this summer and it was great.
