Hello and welcome!
Did you mean ClearStream5 for the VHF antenna?
Just a few thoughts:
1) Is the 7777 configured for "separate" VHF/UHF inputs, and do you have the antennas connected in appropriately?
2) You might want to use the tilt feature of the 91XG mounting bracket to aim the antenna up a little bit toward the sky. You seem to have tall mountainous obstruction close to you, so it may help to have the antenna aimed slightly above the mountain tops.
3) You may want to experiment a bit with the aim of the antenna. When faced with tall mountainous obstructions, the signal might be diffracting over many points along the ridge line. If you aim at different points along the ridge, you might find some spots that produce stronger signals than others.
4) Experiment with the Interactive Maps tool (
here) and try a bunch of different antenna heights (also verify the accuracy of your location on the map). Try 20, 30, 40, and 50 feet to see how much things change. This will give you an idea of whether or not it makes sense to go for more antenna height. The benefit of antenna height mostly depends on how close you are to the nearest mountain obstruction.
5) The 91XG and 7777 are already a pretty good combination. If adjusting your antenna as per these suggestions is still not good enough, it would seem the next steps would be to either increase antenna gain (by ganging multiple antennas), switching to a pre-amp with a lower noise figure (like one from Kitztech), or both.