1. Without power, Amplifier REDUCES the signal strength. It is quiet normal that you got no signal when amplifier is there, but power is missing.Hi ab cd,
All the bits came yesterday so I've set up as shown in the diagram above. I could only find a 12v power source so I've used that. Without the power switched on I get almost no signal from the antenna. When the power is switched on I get roughly the same range as I did without the amplifier in line. Do you think the lack of range with the amp is due to the lower voltage? You mentioned that the amplifiers work best at 15v - 24v
2. The Amplifier are rated to operate on voltages of the Satellite Dish LNB. Most dish LNB operate on 14V to 18V. The amplifiers have some tolerance, so they operate from 12V to 20V. Your 12V should be OK. A bit higher voltage (e.g. 15V) may somewhat improve the range.
I am surprised to note that you get roughly the same range with & without amplifier. This is strange. Something is wrong.