[Elecraft] (phase signals RE: SDR IQ/IF Questions
From: Wes Stewart n...@yahoo.com The LP-Pan works well with a decent soundcard, but suffers from the use of PowerSDR software, which is simply awful in my opinion, and lots of cabling. Spectravue runs with the LP-Pan just fine. I am using the recommended emu-0202 soundcard with a single LP-Pan. The emu connects with a USB and requires two audio cables to the LP-Pan. The LP-Pan uses a BNC coax cable to the K3 IF. One one more connector for 12v. That is more than the coax plus USB cable for the SDR-IQ, but I do not see what the big deal is. But then if you saw the wiring in my shack you would understand that comment. For dual-receive I use the M-Audio Delta-44 soundcard which has four audio cables and a sub-D15 cable to the computer. But this is not a standard application. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com == __ 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
Re: [Elecraft] (phase signals RE: SDR IQ/IF Questions
Thank you for all of the replies everyone! You have answered all of my questions and some of you have gone further! Consider this topic finished! 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
Re: [Elecraft] (phase signals RE: SDR IQ/IF Questions
On Wed, Apr 6, 2011 at 4:52 PM, George A. Thornton gthorn...@thorntonmostullaw.com wrote: 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. Was going to ask this in a separate thread, but when EXACTLY is P3 video output on the roadmap? Its the only thing preventing me from pulling the trigger. Also if I buy one now, can I get the output update later (is this purely a firmware issue?). 73's, -aps (KC2ZSX) __ 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] (phase signals RE: SDR IQ/IF Questions
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
Re: [Elecraft] (phase signals RE: SDR IQ/IF Questions
There is one other consideration with mentioning, and that is that because the LP-PAN uses your computer's sound card, it is at least theoretically subject to image problem as a result of amplitude and phase imbalances between the I and Q channels, where the SDR-IQ passes those data in digital form. Cw Skimmer recognizes this issue and includes automatic amplitude and phase balancing functions in software. 73, Pete N4ZR The World Contest Station Database, updated daily at www.conteststations.com The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at telnet.reversebeacon.net, port 7000 On 4/6/2011 4:52 PM, George A. Thornton wrote: 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:
Re: [Elecraft] (phase signals RE: SDR IQ/IF Questions
The URL posted by Mr. Thornton is part of an excellent mid-level tutorial series, quite worth reading. I wanted to mention, in this mix, another SDR which seems to be somewhat unknown in this country; /vide/ http://www.rfsystem.it/shop/... This receiver PMSDR has T/R switching, covers up into the VHF region, and is physically very small and available in kit form. I had one of the early models, and was quite pleased with its quality. In its newest form, it can serve as a stand-alone unit or as a panadapter with, for example, the K3. I believe there is a US/Canadian dealer. QST's articles do not demonstrate any particular expertise or breadth of knowledge in this field. John Ragle -- W1ZI = On 4/6/2011 4:52 PM, George A. Thornton wrote: ...see for example http://zone.ni.com/devzone/cda/tut/p/id/3013 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. __ 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] (phase signals RE: SDR IQ/IF Questions
Geoff, I have both the SDR-IQ and LP-Pan (but not the P3). Essentially, all are SDR's and convert the RF signal into two signals which are 90-degrees out of phase with each other, thus the I and Q designations. Difference is that the SDR-IQ is a stand-alone receiver covering 500-Hz to 30-MHz and connects directly to a computer using USB (so the I-Q signals are data streams). The LP-Pan is dedicated SDR set on the IF of the K3 (or other radios, if desired) and produces I-Q audio signals sent to a soundcard for conversion to data in your computer. The P3 is a stand-alone panadaptor with built-in SDR for processing the IF from the K3. I bought my LP-Pan for about $150 used. SDR-IQ runs about $500 and P3 even more. You can run a SDR-IQ connected to the K3 IF by tuning it to 8.215 MHz or run it separately. But for your money (if you already have a K3) the LP-Pan is best and will do everything the SDR-IQ does (within the restrictions of the K3). I bought the LP preamps for my LP-Pan as I wanted maximum sensitivity. I recently figured out how to slave two LP-Pan to a single xtal LO so they would be phase-locked and do dual-Rx diversity reception. Info on my website under LINRAD. I only take exception with one paragraph George makes: The K3 takes an RF signal from an antenna, filters and modulates it. The received signal is not modulated. It is filtered, amplified and converted to the first IF for use by external SDR's. The roofing filters do not come into play or the 2nd IF/SDR of the K3, itself. There is no modulation or demodulation by the K3. Demodulation is done by the DSP sw in the computer. LP-Pan is a great little Rx to get acquainted with SDR. 73, Ed - KL7UW -- Message: 51 Date: Wed, 6 Apr 2011 13:52:53 -0700 From: George A. Thornton gthorn...@thorntonmostullaw.com Subject: [Elecraft] (phase signals RE: SDR IQ/IF Questions To: Geoffrey Wolf liltechdud...@gmail.com, elecraft@mailman.qth.net Message-ID: c1a98f53a996d24fb5c20d436c5833049...@nwrrlaw.nwrrlawserver.offsitedataspace.com Content-Type: text/plain; charset=us-ascii 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. 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com == __ 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
Re: [Elecraft] (phase signals RE: SDR IQ/IF Questions
Just a couple of extra thoughts. I use an SDR-IQ as a panadapter on the i-f output of my K3 and it works (*almost) flawlessly. (*I have never found anything with a microprocessor in it to work completely flawlessly). So the SDR-IQ can be used both as a standalone receiver with decent demodulation capability with the supplied SpectraVue software and/or as an excellent panadapter with the same software. This has a good (i.e simple) GUI and serves the purpose well. SDR-Radio is another program that supports the SDR-IQ but it is way too complicated and changes sometimes several times a day. Not ready for prime time in my view. (Flame suit on) The LP-Pan works well with a decent soundcard, but suffers from the use of PowerSDR software, which is simply awful in my opinion, and lots of cabling. I have seen a prototype P3 in action, but don't have extensive knowledge of it, other than to note that the screen is too small for my taste and located in the wrong place. The proposed VGA output will solve the screen size problem, but unless I'm mistaken, precludes the use of the same display for several programs. My current setup has a laptop usually with a web browser displayed and N1MM (if contesting) or DXBase (if DXing), MMTTY and the panadapter window all on a second monitor. For my purpose this is the most functional option. Wes N7WS --- On Wed, 4/6/11, George A. Thornton gthorn...@thorntonmostullaw.com wrote: 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. __ 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
