I don't think a beverage antenna fully meets this requirement. How would it? It is not even matched to your radio.
The S/N (dB) is the difference between the noise and signal of the receiver channel when it is connected to a matched source !
I happen to believe that an antenna that is matched on its band of operation is less noisy than an antenna which is not. That's all !
I am not making any wild claims just giving some observations based on my own antenna experience.
This will be my last post on the subject as I can see others have posted the same concepts.
First, the Beverage is a travelling wave antenna- resonance is not an issue, nor is it desirable. The Beverage is however matched to the receiver by a transformer. The gain is quite low, thus the matching. One might also note that the active antennas are also nowhere close to being resonant- they are a very high Z electric field probe whose impedance is brought down via a source follower or emitter follower.
Matching an antenna to the receiver (at HF) means more signal (and noise in an equal amount) is received. However, efficiency is not an issue at HF. Our noise floor is determined by:
1. Atmospheric noise
2. Galactic noise
3. Manmade noise
If you doubt this, turn your radio on to any HF frequency with no signals, then disconnect your antenna. If the noise level does NOT drop, then there is something wrong with your receiver.
Isn't it odd that the top receive antennas for 160M are all non-resonant, have very low gain, but do have excellent patterns and therefore high RDF?
Receive 4 squares and their ilk- i.e short E field phased verticals
NONE of these antennas are anywhere close to being resonant and yet the world's top DXers all prefer them Hmmmmm.
Check out K7TJR's site of low band receive antennas. For the uninformed, RDF is the figure of merit here- the higher the RDF, the better the antenna (i.e. its ability to reject noise from unwanted directions). Note that the WORST of the lot is a resonant inverted Vee at an RDF of 0.6:
As soon as you find someone to agree with your "resonance is best for RX antennas", let us know Fred. Tom, W8JI is always available to offer his thoughts.