Hi M; Well I'm a hydro / solar guy so my wind knowledge is from other friends who use it.
Your roof bracket from the satellite dish might have possibility's.
I have concerns about it though.
To start, is it really high enough to let blades
free spin?
I've not heard anything about the slope of the roof helping... but it could.
The real possible problem is just how securely that bracket is attached. I could see strong winds ripping it from the roof!
I suggest you start by using a wind meter (anemometer) and find out just how strong and steady your wind is.
I'm always surprised when my wind genny friends complain its not windy enough! You need steady wind at say 7mph min. to start making any power at all and really 15 mph and up is where they start bragging...
I laugh at them because my hydro runs 24 seven, wind, rain ,sun, hot , cold... get the point?
Another thing about wind & hydro is they require a different charge control than solar.
A constant diversion regulator that needs a spot to dump power at any time.
A solar array charge control can switch on and off to regulate power. You can not disconnect an alternator at all if it is spinning.
Find out for real how much steady wind you have. Investigate wind machine's and see how large a prop span they have. How much power they make at what wind speed?
Check costs of genny and regulator & wiring.
Then look into how many solar panels you can buy and upgrade them instead of occasional wind power.... just saying...