True: The best "amplifier" is your antenna.
A roll of wire and a fair knowledge of how to read and to build from an antenna handbook do more for a station than just about anything else.
I agree. I have heard many stations on the air that are both weak and deaf. Obviously with deficient antennas.
Hearing well is just as important as having a good transmitted signal, in my opinion.
Along with this, is elimination of all the local RF noise that you are able: light dimmers, power supplies, battery chargers, computers. Many of these are RF noisy. Put your receiver on battery and turn-off the main breaker to your house for a few seconds. I you're QRMing yourself, you'll know instantly by the drop in background noise. Power ON and check circuit breaker by circuit breaker until you've isolated any noise to a general area and then begin unplugging individual devices.
Since most electronics now contains a SMPS and/or clocked integrated circuits, they will make atleast some RF noise.
Plasma TVs a horrific. Have one in the house (not by choice) and whenever that is on, I get S5-S9+30 buzz from 80m-6m
Luckily the noise blanker in my Icom IC-730 is very effective against it.
Other than that, I haven't had much problems with switching supplies. A notable exception is ironically the chargers for my Baofeng Chinese handhelds. The manual even says not to use it around "communications equipment" (try to figure that one out)
I just unplug them when working HF though
My biggest source of QRM is by far the power lines. It is not constant and depends on the whether. Most of the time they are quiet
but sometimes they can make noise up to S9+ and the NB is useless against it
So far the power company has been of no help
I had a neighbor with a battery charger that caused havoc for me. The boyfriend who owned it eventually fell out of favor with their teenaged daughter and the charger left with him.
I had to read that sentence over about five times before understanding it
If you consistently have a problematic device with the neighbors and it isn't too expensive, you might consider offering to replace it.
Luckily the neighbors are fairly far away around here so no real noise to speak of from them.