I have a Yaesu 991A which has IPO, AMP1, and AMP2 receive amp settings. I spend most of my time on 40m and 20m and usually just keep the setting on IPO. On those bands there is always some slight background static and a noise floor that varies depending on conditions. When I receive a strong signal, I can see the signal clearly on the waterfall and the signal strength meter gives logical readings (i.e 10 over, 9 dB, 5dB, etc).
When I move to some other bands (like 10m) and tune up, the waterfall sometimes shows absolutely no signal when on IPO - not even any background static. I can't hear anything. When I change to AMP1, the waterfall still shows alomost nothing with no noise, but I can hear some signals even though I can't see them on the scope. When I change to AMP2, some background static shows up on the waterfall and I can barely see the signals on the scope just slightly over the noise floor. What is strange to me, is very often these signals are quite strong and very clear but the meter may only show 3 dB. It sounds like a 9 dB signal, but meter only shows 3 dB.
Hoping someone could explain why I have such a low noise floor on these bands (wrong antenna for the band? using a 40m OCFD), how to properly use the receive amp settings, and what signal reports I should give when what I am hearing is much better than what the meter is telling me? I may not have a good understanding of whether a noise floor is good or bad. Seems to me the radio performs best when there is at least some noise floor.
When I move to some other bands (like 10m) and tune up, the waterfall sometimes shows absolutely no signal when on IPO - not even any background static. I can't hear anything. When I change to AMP1, the waterfall still shows alomost nothing with no noise, but I can hear some signals even though I can't see them on the scope. When I change to AMP2, some background static shows up on the waterfall and I can barely see the signals on the scope just slightly over the noise floor. What is strange to me, is very often these signals are quite strong and very clear but the meter may only show 3 dB. It sounds like a 9 dB signal, but meter only shows 3 dB.
Hoping someone could explain why I have such a low noise floor on these bands (wrong antenna for the band? using a 40m OCFD), how to properly use the receive amp settings, and what signal reports I should give when what I am hearing is much better than what the meter is telling me? I may not have a good understanding of whether a noise floor is good or bad. Seems to me the radio performs best when there is at least some noise floor.
