IQ data is a method for describing the characteristics of a wave. IQ uses amplitude and phase angle to describe the wave, see for example
http://zone.ni.com/devzone/cda/tut/p/id/3013 The K3 takes an RF signal from an antenna, filters and modulates it. At some point the filtered, modulated signal is made available to an IF out port where it can be used conveniently by various testing and measuring devices. A panadapter takes the IF signal and converts it into IQ signals. These IQ signals can then be used to visually represent characteristics of the signal on a chart or screen. The LP-pan converts the I and Q signals to audio for input into a computer using a sound card. The P3 panadapter directly charts the IQ data onto the built in screen. The SDR-IQ is a standalone software designed receiver. It is designed to hook directly into an antenna source and can be used with software to directly display data about the signal. I do not believe it is designed to work with modulated IF output from a quality receiver, but I could be wrong. The SDR-IQ can be used as a standalone panadapter through a computer, getting its signal direct from the antenna, completely bypassing the transceiver altogether. According to its own manual it does not have much filtering and it can get overwhelmed by other RF sources. The price for the LP-Pan and sound card is less than the price for the SDR-IQ. The P3 costs only a small amount more than the SDR-IQ. The P3 and LP-Pan were compared in a recent QST article. According to the testers, the two approaches are roughly equal in their ability to decode and display weak signals. The LP-Pan has the advantage of allowing the use of a large computer screen for a panadapter. The disadvantage is that it is complex to set up, requires use of buggy computers and software with driver compatibility issues and has a lot of loose wiring. The P3 is a plug and play solution that is reliable and easy to use. The P3 is more closely integrated with the K3. IN the future the P3 is going to allow direct connection to a computer monitor and keyboard. Given all the factors, I do not think the SDR-IQ solution is the best choice here. From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Geoffrey Wolf Sent: Wednesday, April 06, 2011 10:30 AM To: elecraft@mailman.qth.net Subject: [Elecraft] SDR IQ/IF Questions Hello fellow SDR enthusiasts, I have looked around a little bit and haven't found a very definitive answer for the questions that I'm having about the way the K3 and external SDR equipment works. I've been looking into the LP-Pan which converts the IF output from the K3 into (im guessing) audio signals which then are converted into digital data by a soundcard. The trouble I'm having is understanding what exactly I/Q is. >From what I understand, I/Q is digital data that software like CW Skimmer understands. Now, I've also been looking at the SDR-IQ which does all of this internally by taking the IF output from the K3 and converts it directly into digital data which is then ferried to the computer over USB, forgoing the need for an extra soundcard. Now, I've seen two versions of PowerSDR. I've seen PowerSDR/IF (looks more developed/supported), and PowerSDR-IQ. What is the difference? I suppose the summary question of this email is. can you use PowerSDR/IF with an SDR-IQ rather than an LP-Pan? I personally would rather buy an SDR-IQ and take that extra hardware stage (possible audio loss) out of the picture. Thanks! Geoffrey Wolf AB3LS - Amateur Radio Callsign University of Pittsburgh '14 gr...@pitt.edu liltechd...@me.com (412) 450-1310 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
