Tip #6 - Playing the S/N game rather than bending the S-meter
A untuned low-q loop is about 30dB lower in signal strength than a well placed dipole or vertical. Even with tuning, you can expect about 20dB less. The best solution is to WAIT if you don't hear anything at first. You could overcome this with a preamp, but you haven't changed the S/N ratio, only affecting the overall level of signal AND noise. Only the directivity of the small loop is creating the ratio.
(If you want to get into the magnetic-vs-electrical aspects of small loops - great. If I was a betting man, 99.99% of your noise nulling ability is in the far-field electrical signals - loop fanatics can go here if they want, but I won't start that now. You can solve the question if you build the loops out of coax by placing a snap-on ferrite on one of the arms of your coax loop and discovering that it won't work anymore. Some other time perhaps.
Here's how it goes: You spend an afternoon building this thing and rush into the shack to hopefully see the s-meter bent. Drat. Band isn't open. Local signals are way down since you have this mounted low, and your feedline braid is well choked. About all you can do is null the noise that you do hear with rotation. Hey, let's at least peak up on that with the tuner, and null it again. Wow, even the tuner is hard to peak up with by ear.
Before you ball the whole thing up and sign it off as the most complicated dummy load you've ever built - just WAIT.
You may have never heard your receiver's actual noise floor before! There isn't enough noise to actually tune with, although you may get lucky by purposely trying to peak the man-made noise before the band opens. Forget the locals - that isn't what you are interested in anyway probably.
When the band does open, do yourself a favor and tune by ear, and not by eye! Put a piece of tape over your s-meter if you have to. Unfortunately, we don't have a S/N meter on our rigs, but only an S-meter.
What I'm getting at is that your neighbor with his perfectly high dipole might receive an S9 on the same signal you are listening to. Yet you are only peaking at about S5. Then you hear his noise level is about S7 when the transmitter drops. With your loop, the S-meter drops to the bottom peg and would go further if it had the room.
Bottom line: Your neighbor will listen to about a half-hour of that poor S/N ratio before throwing the headphones down in disgust. You on the other hand will be able to listen the entire night with armchair-copy, even though you aren't giving your S-meter a workout. So don't judge your loop by S-meter alone. Listen to the S/N *ratio* instead.
Don't be afraid to crank the volume. It will be a LOT cleaner than before.
Here is the ironic part: With a good s/n ratio from your loop, you just may start to hear the weaker noisemakers that were formerly "in the grass" so to speak that were undetectable from your formerly high noise level! At least they are much easier to deal with.
In the end, I really like small vertical loops. However if you are not constrained by space or noise issues, or just want to build one for kicks, there are better alternatives!