I used to live in the worst HOA ever - military housing. After that I lived in a house on the national register, no visible antennas. Then I lived in an apartment building with no yard and only a small community patio space. I operated HF at all of them, and not one mag loop.
You were HOW OLD when you had these experiences? Did they even have consumer mag loops back then?
Fast forward to today and operating "portable" often results in people buying small loops and highly loaded antenna contraptions which might offer a "match" but especially QRP are frustrating at best to make contacts with. You spend more time futzing around setting up and adjusting these antennas than making contacts in the field.
As I clearly understand, there is a lot of "futzing" designing, installing, testing, tuning, retesting, rinse and repeat several times ad nauseum to get a long wire or any other "home brew" in a highly constrained location to work wellish. Or I could futz less with something that works reasonably well while transmitting and receiving, but obviously not up to
your self-imposed standard.
So from my perspective of over 40 years in this hobby operating HF in all manner of locations, you don't start with the poorest performing antennas, you go with the best performing ones you can possibly have.
And that is the key. 1) Your perspective after 40 years experience in making antennas 2) Your assumption that your "best performing" solution is achievable in my environment with my set of circumstances and abilities.
Nearly always this will be a wire antenna.
With emphasis on "nearly" while ignoring other impinging and critical factors.
Sometimes you have no other choice but I wouldn't introduce limitations that don't actually exist.
Again, and this is key:
An assumptions that my "limitations...don't actually exist." Do "age" and "physical abilities" count as "self-imposed?" Is lack of 40 years in ham radio building antennas "self-imposed?"
What does "Fairly stealthy (mounted low, not conspicuous)" actually mean? So a 3' loop on a stand is OK, but something like a nearly invisible wire or vertical isn't?
I was describing characteristics of a magnetic loop antenna. Then you compared it to something I consider "infeasible" (long wire) due to my "self-imposed" (read allegedly "unreasonable") constraints.
Would inconspicuous be OK?
Yes, that is one objective. But not via something that I consider infeasible.
But there's a house, right? Houses have height, length and depth, same dimensions as antennas.
Again, assuming that what is feasible for you is also feasible for me. My "house" is an attached multi-family condo in an HOA with heights that are a "no-go".
Is in-shack tuning ruled out?
No. In fact, that is a requirement for any antenna I install.
"Avoiding an antenna-building hobby" is a tight constraint. You have a very specific set of operating conditions which demands a custom built solution.
"Demanding" a custom-built solution is based on your needs, expectations, objectives and capabilities. Not everyone is you. The great thing about the ham radio or any hobby is that we don't need to react to the "demands" that are defined by someone else.
You are binding yourself to find the lowest common denominator solution, eliminating even simpler, less expensive and better performing ones. Yes, you or someone else might have to build and install it (somehow you managed to get a G5RV jr on the roof...).
And that roof-mounted G5RV is not the type of project I care to repeat.
Again, "simpler" and "better performing" (based on my abilities and limitations) is from YOUR perspective and abilities. Such will not be "simpler" from my perspective. And while "better performing" is an ideal, it is irrelevant if not achievable based on my circumstances, abilities and constraints.
My "abilities" do not match yours. My "limitations" do not match yours. My limitations are not self-imposed, that is unless you consider age and level of physical abilities to climb and hang off ladders "self-imposed."
You just have to weigh the option of an expensive poor performer that's plug and play, or stretch a bit and end up with something that will offer a better operating experience.
Weighing I must. Weighing I do. All antennas are some level of compromise. "Poor performer" is relative to one's objectives and expectations. What is "poor performer" to an individual with 40 years in the hobby is not necessarily that to one who has different skills, abilities and unavoidable (not "self-imposed") constraints.
There are some here who would rather get on the air with more compromise than others rather than try to do what they are not capable of just because someone else believes differently.