Comparing GP and delta loop in receiving

As known in theory, vertical antennas are more noisy than loops and horizontal dipoles. Especially loops are known as being very "silent" in listening. Here is my test: I recorded a CW transmission on 40m during daytime. The vertical is a 10m high 1/4 GP with three radials. The loops is an 80m inverted vertical delta loop.  During the recording session I switched the GP and loop antennas back and forth. I think also you can hear the difference:

https://docs.google.com/open?id=0B_fYzTGwQBNgdmd5Z1pSLVV3WUk

Also the signal might be slightly weaker with the loop, but don't you agree: more convenient to listen! I have checked this also with really weak JT65 signals: The loop reveals signals that are hidden in GP noise, because signal-to-noise-ratio (SNR) is more significant than the signal level!

I tried also the 20m loop for listening on 40m band...of course also that is more silent, but also the signal was considerably weaker.

Still, my GP is generally better in transmission, especially when it comes to longer distances...so in order to optimize my DX hunting I should use separate listening antenna and transmission antenna. Luckily there is a mod done in my TS-850S to enable that.