Question about optimal H-field antenna placement for noisy urban areas

[alicesphere]

Hi everyone,
I’m new to the forum and still learning how the Blitzortung/LightningMaps system works, so I hope this is an appropriate place to ask. I’m considering setting up my first H-field station in a fairly dense urban area, and I’m trying to understand what kind of antenna placement would give the best results.
My main concern is electrical noise. I live in an apartment building with plenty of nearby power lines, elevators, and general broadband interference. I’ve read that proper antenna orientation and distance from buildings can make a big difference, but I’m still uncertain about what is “good enough” before I invest in a kit.
A few questions:

1. How far from a building wall or metal balcony should an H-field antenna ideally be placed to reduce noise pickup?
   
2. Does height matter more than horizontal distance from electrical sources?
   
3. Would placing the antenna on a rooftop help, or can rooftop equipment (HVAC, solar inverters) actually make interference worse?
   
4. Are there any practical noise-testing steps I can do before buying hardware?
   

I’d really appreciate any tips from members who run stations in similarly noisy environments. Looking forward to learning more and hopefully contributing to the network soon!