My main HF listening antenna for the past year or so has been a ~150 ft. random wire up between two trees on my property. I'd been noticing that it wasn't very effective at the upper ranges of the HF spectrum so decided to resurrect my old Cushcraft trap vertical. When we first moved in here I had it up on a corner of the house, but I had so much noise there (probably due to its proximity to power lines on the north side of the house and not having a good ground) I had about an S9 noise floor but little signal. This weekend I put it up next to the garage and it is working great. I still need to run a few ground radials, install a grounding rod, and get about 100' of coax and run it properly under the eaves of the house and garage rather than the just-long-enough coax running across the ground from the window to the house. But for now it works.
I built a switchbox to be able to switch between either the wire or the vertical, and to switch both of them in together if I want. I've found that on some signals with selective fading, it helps to have both antennas connected since sometimes the horizontal polarity fades but comes in strong vertically, and vice-versa. I've noticed that signals which were coming in OK on just one antenna really jump up a few S-units when both are switched in. This is what I learned in the military is called polarity diversity. There's also the advantage of space diversity, but my two antennas probably aren't far enough apart to take advantage of that.
At any rate, I should be able to pick up signals in the upper HF spectrum better. With the 10/11 meter opening this weekend, I definitely noticed a difference between the vertical and the wire.