First .. I found most programs that you can use for the Soft66 didn't begin to compare with a program called Winrad. While I strongly suggest that you look at Winrad, that does not appear to be your problem. The Soft66 is a very sensitive receiver and signals should be obvious. If you are not seeing signals, try connecting an antenna directly to the input of the 4066 chip and bypass the input filter. I had a problem with mine that turned out to be a bad solder connection in the filter (darn enamel coated wire) and I had the same symptoms. The biggest problem that you might have beyond that is your I/Q connection. If they are backwards, you will see LSB signals as USB etc. You should still hear them, except that it will be confusing. You should do the I/Q balance adjustment but it will not keep you from hearing signals. Winrad has a good set of instructions that tell you how to do it. Also, the online instructions for building the Soft66 are very difficult to follow but for $21 ehh. Be sure that you have installed the jumper. With no LO you won't get signals either.
As to what you should see (reference Winrad): Set the LO frequency display to 7060 khz. With a normal soundcard that can sample at 48 khz, you should see 24 khz above the LO frequency and 24 khz below the LO frequency. and yes if the I/Q connections are reversed, so will the frequency representations. In other words with a 48 khz sample rate, you will see a 48 khz chunk of spectrum, all at the same time. Better soundcard, more $$$, higher sample rate, more coverage! There will be a highlighted area on the pandisplay that indicates where you filter is allowing you to hear. You can adjust the filter width and move the filter and that will allow you to select which signal in the 48 khz that you want to hear. Selecting the correct mode will allow you to sit back and listen. 1. The hardware is solid 2. The software is super solid 3. I hope to have helped your concept! Good luck. Larry W8ER sbumpous wrote: > > 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. > >
