Reverse Sweeping on RPD's & AOI Gear
Curious to see if anyone else out there has had a similar experience. It seems the new 1.8 AOI amplifiers do NOT like a high upstream EQ, they unevenly adjust the tilt and create a roll-off below 100mhz. The pictures I posted are exaggerated examples of min-max tilt, but demonstrates the problem. Our system is rural, so it's not uncommon to have long trunk spans exceeding 2500' (this is with either 750p3, 750mc or 875p3).
The tilt seems to adjust okay between 0-8/9db, but once you go above 10, the roll off is high. Combine this with the fact you have more attenuation at 204, which can't be "flattened" out with the EQ, and once you get 6/7 amps deep, you get what I call the "frowny face" response, being a tilt on both the high and low ends of the return. This is inverse to the power level, where the beginning of OFDMA2 will be maybe a 34, with the high end closer to a 40.
So please tell me, am I crazy, or is anyone else seeing this in the field? Thanks!