[timgr]

Test with the cheap antenna. It's just a test instrument. Use it to test signal strength and then throw it away. If the reception in the attic is lousy, it will give you an idea of what to expect from a bigger antenna. Compare the results to what you get on the roof.

If you get lots of channels with the $6 antenna on the roof, and nothing in the attic, then you know what to expect.

If you want, you can test with the ANT751. Or with the GE antenna. (BTW an "attic antenna" is just an outdoor antenna that is not weatherproof. Marketing only.) Buy it from your local Walmart, and return it if the results in the attic are not satisfactory.

Look, you don't lose some signal in the attic. An attic surrounded by stucco and concrete is a particularly bad attic for an antenna. You lose A LOT of signal in the attic. But you have A LOT of signal in the air. It might work. If you want to try it, doing some simple tests may reduce the uncertainty.

Digital TV is not like radio, or the old analog TV. Either it works perfectly, or you get nothing. If you are on the border, it will work sometimes, and pixelate or go away occasionally. But if you get a reliable picture, there is no way to tell from the TV picture whether that is a strong signal, of just an adequate signal. So read the online reviews with that in mind.

The RIGHT way to do this is to buy the ANT751 that you were happy with, and put it on the roof. Attic installations are very uncertain. No amount of discussion will remove that uncertainty.

For your tests, many TVs will tell you the strength of each channel, and the signal quality. If yours does not, you could just count the number of channels you get in each location, and compare.

If you want to go all out for the attic, with no additional testing, buy an Antennas Direct DB8 and put it in your attic pointed at Phoenix. That's within your $100 budget, and it's a very sensitive UHF antenna. But the results may still be unsatisfactory ... there's no way to know without testing it.