Something like this but pvc.
https://www.amazon.com/WINEGARD-SW-0010-Tripod-Mount-Antenna/dp/B001DFZ5J2
if you want a proper mount, and not my mac-guyvered solution, (two closet rods pounded together, and held up with bungee cord and bailing wire), then here is everything you will need:
Of course, this assumes you have adequate lengths of coaxial wire to attach your antenna to the flatwire, and run it in from your impromptu "demarkation point" to your television.
Yes. You need a tripod. On the legs of the tripod, you can either use concrete blocks to hold it down, or sand bags.
Generally 2 antennas will be needed, would probably recommend a simple wire antenna for receiving on HF/SW but if you got money and want something small and compact I have heard great things about the DX Engineering - Pixel Technologies RF PRO-1B (The Northern Alberta Radio Club has one out at their club site).
For higher frequencies (above 30Mhz) a discone antenna would do very well. They don't have any gain, but they are very wideband. I have the Diamond D3000N that I'm quite impressed with, it does 25-3000MHz receive and even allows transmit anywhere between 50 and 1300MHz.
However if you want to be able to receive weak signals like ATC is from the northside, I would probably either buy or more likely build a yagi antenna. A yagi is a directional antenna, which means it has gain in a certain direction, the gain essentially amplifies the signal. Yagis are however rather narrow band, only a couple dozen mhz or so.
I will also link below the poles I was talking about from PA. You can probably rig something to support them, but I use this tripod as a base support and some 325 paracord for guying. It works well, the mast supports a discone as well as a couple of wire antennas.
Links for PA. Aluminium Poles ($12.99) / Fiberglass Poles ($3.99)
Now that they're in the red, (except for PBS), you should be able to pick them up with the antenna, and the preamp. There are tripod mounts, and interlocking antenna masts available, so since you're on the top floor, you could use 3 of these to get it up to 48 feet. You're going to want to anchor down the tripod mount so it doesn't tip over, and use a system of guy wires to stabilize the antenna, (ideally mounted to the building, but you could use cinder blocks to hold it stationary if you're not allowed to modify the building.
Since you're on the third story, that would place you at 30 feet if you just set your antenna on the deck. With the tripod, that'll add 3 more feet, plus a 5-foot extension rod, you'll be up to 8 more feet for an AGL height of 38 feet That would be even with your roofline, most likely. Then add on 2 more to reach 48 feet AGL, or 10 feet above the roof line.
A preamp will enable you to pull in steady signals. It will amplify the strength of the reception, but also increas the SnR ratio. The CM-777 specifically is designed for extreme fringe areas where the closest tower you're going to be pointing at is over 80 miles away, as it has a 30dBi gain. Any closer, and you may overload your television tuner, and not be able to pick up anything. For most applications, the CM-7778 would be a better fit, as that only has 16dB of gain. Note that even though you will be pointing it north, you'll still be able to pick up stations directly opposite of the antenna off of the back end Even though you're looking at a direction yagi antenna, it will pick up a range of approximately 30 degrees. Channel 15 and 30 would likely be overloaded with the CM-7777, but not the CM-7778.
Note that the CM-3020 is a VERY large antenna, at a size fully assembled of 152 x 95 x 22 in (12'8" x 7'11" x 1' 10") You're going to need to put it up on a pole clearing the roof line.