OK, guys, call me a lumberjack...I'm stumped. I can't figure out the I/Q balance / image rejection thing.
I am using the soft66 radio bought on ebay. Center frequency is 7060 khz. Using SDRadio/Rocky/and several others, I see a spectrum display that is perfectly symeterical around the 7060 center frequency. My idea of what I should see, if the audio is balanced, and everything is in the correct quadrature relationship is that signals below 7060 would not be mirrored above 7060, and that the same would hold true for signals above 7060. Otherwise, how do you know which frequency you are actually listening to?? Rocky is supposed to do automatic adjustment, but I see no data appear in the RX I/Q balance screen. Maybe this receiver is not sensitive enough to provide signals strong enough for Rocky to analyze.?? Using SDRadio, and the adjustment for sound card "skew", I am unable to see any action such as I expect to see. When adjusted to the extremes, I do see what looks like a notch appear either above or below the 7060 center frequency, but it is very narrow, and only affects a small range of frequencies. The "mirroring" effect described above still occurs on all other frequencies. PowerSDR only shows me 1/2 the spectrum (i.e. 7060 to 7084), but that doesn't mean I am not looking at images from the lower side. I have used three different computers, and four different sound cards with no substantial change in what I am seeing. What am I missing here? Shouldn't a correctly balanced I/Q phase and ratio balance out the images on both sides of the center frequency? Or does the null only work at one frequency? Any help would be appreciated in understand whether: 1. my concept of what I should see is wrong 2. the hardware is problematic, 3. the software is problematic Thanks in advance for your advice.
