SDR-IF and I/Q questions
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Don,
Not trying to be argumentative, but... The SDR-IQ uses a USB-2.0 interface and not audio. Some SDR actually provide A/D conversion inside the box with digital output streams. The units you mentioned are audio-baseband. The only issue would whether one needed a good soundcard or not. I understand that many sw provide for radio control so need that access (whether via USB or RS232). K3 being one of those that offer external control. I wonder if the KX3 will have that ability, as well? Very handy for the "click frequency" operations on sw like psk-31 (variants). The eme SDR sw (Linrad) that I am using has this ability (if proper drivers are available for the radio). ------------------------------ Message: 37 Date: Thu, 10 Nov 2011 07:42:12 -0500 From: Don Wilhelm <[hidden email]> Subject: Re: [Elecraft] SDR-IF and I/Q questions To: [hidden email] Message-ID: <[hidden email]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Ed, The I/Q outputs are baseband audio - just as would be the case with the output of LP-Pan, or a Sofrrock receiver, or most any SDR receiver. The serial (or USB) port is only used when rig control is introduced in addition to the panadapter function. 73, Don W3FPR 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-? DUBUS Magazine USA Rep [hidden email] ====================================== ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Ed,
The SDR-IQ apparently uses the USB connection for both audio stream and rig control, but the KX3 does not. The I/Q output of the KX3 is baseband audio, which would need to be fed to a soundcard. The rig control is separate and will communicate with the KX3 through the RS-232 serial connection, so if you don't have a real serial port, you will need a USB to serial adapter to achieve that connection. BTW - there seems to be nothing "universal" about the "Universal Serial Bus" - each device version seems to be different requiring its own driver. OTOH, the basic RS-232 port has always been "universal" - it just works because there are no "bells and whistles" (but that is getting a bit off-topic, thanks for listening to my rant). 73, Don W3FPR On 11/10/2011 5:28 PM, Edward R. Cole wrote: > Don, > > Not trying to be argumentative, but... > > The SDR-IQ uses a USB-2.0 interface and not audio. Some SDR actually > provide A/D conversion inside the box with digital output > streams. The units you mentioned are audio-baseband. > > The only issue would whether one needed a good soundcard or not. > > I understand that many sw provide for radio control so need that > access (whether via USB or RS232). K3 being one of those that offer > external control. I wonder if the KX3 will have that ability, as well? > > Very handy for the "click frequency" operations on sw like psk-31 > (variants). The eme SDR sw (Linrad) that I am using has this ability > (if proper drivers are available for the radio). > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
Ed,
Don's comments about a serial port being unnecessary was with respect to the KX3 specifically, not the SDR-IQ. The KX3 will provide baseband "audio" output, which will need to be fed into the stereo input of a soundcard on a computer for panadapter capability. Think of it as having an LP-Pan built in. If one wants "point and shoot" functions from the panadapter software, then a USB/serial control port back to the KX3 will be needed. And yes, the KX3 will have that capability as it has already been announced that the KX3 will use a subset of the K3 command structure. (there is a serial port on the KX3). Also, a USB interface device for the KX3 is also in the plans from Elecraft. It will connect to a USB port on the computer, and have the required connector on the other end to plug directly into the radio. I hope this helps clear up any possible confusion. 73, Bruce, N1RX (original message) Don, Not trying to be argumentative, but... The SDR-IQ uses a USB-2.0 interface and not audio. Some SDR actually provide A/D conversion inside the box with digital output streams. The units you mentioned are audio-baseband. The only issue would whether one needed a good soundcard or not. I understand that many sw provide for radio control so need that access (whether via USB or RS232). K3 being one of those that offer external control. I wonder if the KX3 will have that ability, as well? Very handy for the "click frequency" operations on sw like psk-31 (variants). The eme SDR sw (Linrad) that I am using has this ability (if proper drivers are available for the radio). ------------------------------ Message: 37 Date: Thu, 10 Nov 2011 07:42:12 -0500 From: Don Wilhelm <w3fpr at embarqmail.com> Subject: Re: [Elecraft] SDR-IF and I/Q questions To: elecraft at mailman.qth.net Message-ID: <4EBBC6A4.4020700 at embarqmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Ed, The I/Q outputs are baseband audio - just as would be the case with the output of LP-Pan, or a Sofrrock receiver, or most any SDR receiver. The serial (or USB) port is only used when rig control is introduced in addition to the panadapter function. 73, Don W3FPR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
was hoping that the KX3 may end up as a kinda Flex Lite with access via a program or as a portable field unit Ohhh its so good ! Bob On Thu, 10 Nov 2011 17:43:22 -0500 Don Wilhelm <[hidden email]> writes: > Ed, > > The SDR-IQ apparently uses the USB connection for both audio stream > and > rig control, but the KX3 does not. > The I/Q output of the KX3 is baseband audio, which would need to be > fed > to a soundcard. The rig control is separate and will communicate > with > the KX3 through the RS-232 serial connection, so if you don't have a > > real serial port, you will need a USB to serial adapter to achieve > that > connection. > > BTW - there seems to be nothing "universal" about the "Universal > Serial > Bus" - each device version seems to be different requiring its own > driver. OTOH, the basic RS-232 port has always been "universal" - > it > just works because there are no "bells and whistles" (but that is > getting a bit off-topic, thanks for listening to my rant). > > 73, > Don W3FPR > > On 11/10/2011 5:28 PM, Edward R. Cole wrote: > > Don, > > > > Not trying to be argumentative, but... > > > > The SDR-IQ uses a USB-2.0 interface and not audio. Some SDR > actually > > provide A/D conversion inside the box with digital output > > streams. The units you mentioned are audio-baseband. > > > > The only issue would whether one needed a good soundcard or not. > > > > I understand that many sw provide for radio control so need that > > access (whether via USB or RS232). K3 being one of those that > offer > > external control. I wonder if the KX3 will have that ability, as > well? > > > > Very handy for the "click frequency" operations on sw like psk-31 > > (variants). The eme SDR sw (Linrad) that I am using has this > ability > > (if proper drivers are available for the radio). > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > The New "Skinny" Fruit How This Strange 62-Cent African Fruit Is Making Americans Skinny. http://thirdpartyoffers.juno.com/TGL3141/4ebc89e999482767afm03vuc ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
Don, (responding to your paragraph below)
Here is where I have been at for awhile. I have tested the output on the I/Q leads with a O-scope and they are certainly close. Rocky verifies that, and shows them within a dB. WinRad shows 90 degree phase, (and no mirror images). Neither my soundcard, nor my SoftRock have adjustments for balancing the I/Q leads further. It would be nice if the Audio Mixer Software did this. I wonder if some do? So having a soundcard that provides for balance may be the focal point for the solution to this problem. (Provided that ground loops do not exist.) Thanks again, Dick, n0ce -------------------------------- Dick, The cause of mirror images is normally associated with the two audio signals not being of equal amplitude and/or not 90 degrees out of phase when they enter the "number crunching" part of the software. Yes, "ground loops" can cause that, but check your cables for integrity and be certain the volume controls for the "left" and "right" channels are producing the same amplitude input. Some experimentation with the level controls may be necessary. 73, Don W3FPR ---------------------------------- Richard Fjeld [hidden email] I'd rather be learning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Dick,
If there are no images with Rocky or WinRad, but you do get them with another application, I would suspect the application settings. 73, Don W3FPR On 11/11/2011 1:27 PM, Richard Fjeld wrote: > > Here is where I have been at for awhile. I have tested the output on the I/Q leads with a O-scope and they are certainly close. Rocky verifies that, and shows them within a dB. WinRad shows 90 degree phase, (and no mirror images). > > Neither my soundcard, nor my SoftRock have adjustments for balancing the I/Q leads further. It would be nice if the Audio Mixer Software did this. I wonder if some do? > > So having a soundcard that provides for balance may be the focal point for the solution to this problem. (Provided that ground loops do not exist.) > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Richard Fjeld
Thank you, John, for posting this. (see below)
I was going to comment that articles I have read say the software adjusts the phase of the I/Q signals in the soundcard to cancel images. You have said it well. WinRad & HDSDR, perhaps others, are doing it well. It seems to be a weak spot with PSDR-IF related software. Thaks for sharing the Infrasonic related info. Dick, n0ce _________________________________ The Infrasonic Quartet card (stereo, 192 kHz) comes with a small applet, called "FREEMIXER Panel," that works outside of the WIN sound management system. This helper app allows one to independently play with the levels (not the phase) of the incoming I/Q stream. I imagine other fast cards come the same way. Several of the SDR programs also have an "image killer" available. I am guessing when I say that this "image killer" works by adjusting the phase (time delay)...the ones I have used are offset-specific WRT the particular image that is removed. John Ragle -- W1ZI _____________________________ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Richard Fjeld
To those of you who have been using HDSDR, and commenting on setting the offsets, I found the little Manager button handy to the right of the LO frequency on the face of the GUI.
>From there, you can select 'USER' and make up a list of your favorite frequencies with both the LO and the TUNE frequency settings. When you want to go to one of your frequencies on the list, just double click on it and you are there, all set properly. Richard Fjeld, n0ce [hidden email] I'd rather be learning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Edward R Cole
Well Dave, maybe I am missing something here, but this thread has been
about the anticipated KX3 and having a Pan-Adapter to use with it. As I understand it, the I/Q leads are being brought out, but not the IF. So other SDR receivers, or adapters, are not needed. Therefore, we are down to finding acceptable software, soundcards, and computers to make it work on a par with a P3. The programs I tried that are not producing mirrored images are lacking good control between radio and software. No 'search and pounce' capability, and time consuming to adjust as the frequency was changed beyond the display width. Not hardly on a par with a P3. Perhaps there is something out there that I am not aware of. I'll concede that, but if it is a commercial product, I want to exercise 'buyer beware'. I find PSDR-IF would be a very good match if it wasn't for the mirrored images that fills a crowded screen. Thanks to a fine gentleman who sent me this link, it shows I am not the only one having this problem. Go to: http://groups.google.com/group/powersdr-if-stage/search?group=powersdr-if-stage&q=image&qt_g=Search+this+group and click on the posts with "image" to see all the posts on this topic. Many people are having trouble with it. AND, it pretty well identifies the problem. If it ever gets fixed, we will have something encouraging. At the speed it is going, it may be only for younger people. 73, Dick, n0ce _________________________________ What specific shortfalls in SDR applications that don't have images lead you to conclude they are inferior to the P3? Also, keep in mind that "SDR" is not completely defined by soundcard-based configurations. Have you considered other computer-based SDR front ends like SDR-IQ or QSR-1 before making such a blanket assessment? Dave AB7E __________________________ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Greetings to Don Wilhelm and others, I'm a couple Digests behind and I am responding to Vol 91, Issue 13. I have had responses similar to the following: ............................................. I believe you are mixing two things (given the last paragraph of your post). The SDR software application has no connection with the serial or USB connection to the transceiver - the I/Q outputs are fed to the soundcard and those alone can provide a panadapter type display with no serial connection at all. ..................................................... I knew I should have explained why I asked that. If ground loops are involved in the mirrored image problem, as some have suggested, the RS232 arrangement could be a factor (depending upon how they are wired of course). In the meantime, I have installed NaP3 and it seems to have very good control between radio and software. It is trimmed down from about 30 Mb (PSDR-IF) to less than 4 Mb (NaP3). I read it is taken from a newer version of PowerSDR which is good. I still have numerous mirrored images with it which I will have to get to the bottom of. That is why I asked the questions, to see if I can determine a focal point. By the way, when I installed both PSDR-IF and NaP3, I got a pop-up error message 2908 that I can't get away from unless I do a Ctl-Alt-Del. If you get this, I found a work-around solution. So far, it looks like NaP3 is what I have been waiting for. I haven't responded to all the replies I have received, but I am considering all of them and I thank you. I would still like to have some input (it can be off line if you like) of whether or not you have been successful at running a 'computerized pan-adapter' so that I can weed out the common denominator of this mirrored image problem. I'd like to know YES, or NO, and cpu type and speed, OS, soundcard, if USB to serial adapter or straight serial cable, and the SDR program . Thanks, Dick, n0ce ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Dick,
The cause of mirror images is normally associated with the two audio signals not being of equal amplitude and/or not 90 degrees out of phase when they enter the "number crunching" part of the software. Yes, "ground loops" can cause that, but check your cables for integrity and be certain the volume controls for the "left" and "right" channels are producing the same amplitude input. Some experimentation with the level controls may be necessary. 73, Don W3FPR On 11/11/2011 3:45 AM, Richard Fjeld wrote: > Greetings to Don Wilhelm and others, > > I'm a couple Digests behind and I am responding to Vol 91, Issue 13. I have had responses similar to the following: > ............................................. > I believe you are mixing two things (given the last paragraph of your post). > The SDR software application has no connection with the serial or USB > connection to the transceiver - the I/Q outputs are fed to the soundcard > and those alone can provide a panadapter type display with no serial > connection at all. > ..................................................... > > I knew I should have explained why I asked that. If ground loops are involved in the mirrored image problem, as some have suggested, the RS232 arrangement could be a factor (depending upon how they are wired of course). > > In the meantime, I have installed NaP3 and it seems to have very good control between radio and software. It is trimmed down from about 30 Mb (PSDR-IF) to less than 4 Mb (NaP3). I read it is taken from a newer version of PowerSDR which is good. I still have numerous mirrored images with it which I will have to get to the bottom of. That is why I asked the questions, to see if I can determine a focal point. > > By the way, when I installed both PSDR-IF and NaP3, I got a pop-up error message 2908 that I can't get away from unless I do a Ctl-Alt-Del. If you get this, I found a work-around solution. > > So far, it looks like NaP3 is what I have been waiting for. I haven't responded to all the replies I have received, but I am considering all of them and I thank you. > > I would still like to have some input (it can be off line if you like) of whether or not you have been successful at running a 'computerized pan-adapter' so that I can weed out the common denominator of this mirrored image problem. I'd like to know YES, or NO, and cpu type and speed, OS, soundcard, if USB to serial adapter or straight serial cable, and the SDR program . > > Thanks, > > Dick, n0ce > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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The Infrasonic Quartet card (stereo, 192 kHz) comes with a small applet,
called "FREEMIXER Panel," that works outside of the WIN sound management system. This helper app allows one to independently play with the levels (not the phase) of the incoming I/Q stream. I imagine other fast cards come the same way. Several of the SDR programs also have an "image killer" available. I am guessing when I say that this "image killer" works by adjusting the phase (time delay)...the ones I have used are offset-specific WRT the particular image that is removed. John Ragle -- W1ZI ===== On 11/11/2011 8:11 AM, Don Wilhelm wrote: > (snip) ...The cause of mirror images is normally associated with the two audio signals not being of equal amplitude and/or not 90 degrees out of phase when they enter the "number crunching" part of the software... ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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John, do any of the SDR programs you mention allow you to monitor the two audio outputs AFTER the inserted phase shift? Here's why I ask, although it is essentially unrelated to a normal SDR application ... I'm convinced that we should be able to use the diversity feature of a K3 with both receivers to spacially discriminate against an unwanted signal. We should be able to do it in the horizontal plane by feeding two vertical antennas into the K3, one into each receiver. We might be able to partially do it in the vertical plane by, for example, feeding two stacked antennas on the same tower into the K3 .... one into each receiver. All we need is a variable phase shift in the audio since phase is preserved in the conversion from RF to audio. I've searched for normal audio processing software to accomplish this (volume equalization, phase shift, inversion, sum), but so far haven't found anything other than some extremely expensive professional audio stuff for large auditoriums. I've always thought that something like this could be built into the K3 internal software, maybe using the VFO B knob to adjust the phase. The K3 phase lock in diversity mode is not determinant (the actual phase is essentially random at any frequency) so the null would have to be readjusted at each frequency, but I still think it would be a neat capability. At one point (more than a year ago) Elecraft sounded mildly intrigued by the idea when I first suggested it, but I don't think they've spent any time on it. 73, Dave AB7E On 11/11/2011 6:54 AM, John Ragle wrote: > Several of the SDR programs also have an "image > killer" available. I am guessing when I say that this "image killer" > works by adjusting the phase (time delay)...the ones I have used are > offset-specific WRT the particular image that is removed. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Richard Fjeld
I didn't get any responses to my questions asking for info about those who were successfully running SDR-IF software on a par with a P3, or from those who were not successful.
I did not find any ground loops in my system, and I still do not know why some SDR-IF programs run with mirrored images and a few do not. IMHO, those that do not have mirrored images with my computer, are not on par with a P3. So, I am moving on to other things. I have decided that, at my age, life is too short for SDR. I am greatly disappointed to learn that the KX3 will not accept a P3. Richard Fjeld, n0ce [hidden email] I'd rather be learning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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What specific shortfalls in SDR applications that don't have images lead you to conclude they are inferior to the P3? Also, keep in mind that "SDR" is not completely defined by soundcard-based configurations. Have you considered other computer-based SDR front ends like SDR-IQ or QSR-1 before making such a blanket assessment? Dave AB7E On 11/13/2011 11:49 PM, Richard Fjeld wrote: > I didn't get any responses to my questions asking for info about those who were successfully running SDR-IF software on a par with a P3, or from those who were not successful. > > I did not find any ground loops in my system, and I still do not know why some SDR-IF programs run with mirrored images and a few do not. IMHO, those that do not have mirrored images with my computer, are not on par with a P3. > > So, I am moving on to other things. I have decided that, at my age, life is too short for SDR. > > I am greatly disappointed to learn that the KX3 will not accept a P3. > > Richard Fjeld, n0ce > [hidden email] > I'd rather be learning. > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Richard Fjeld
Richard, SDR is essentially a direct conversion radio, so it is much simpler than conventional heterodyne radio. If you want to use SDR_IF you will need something like additional SDR, like S oftRock to convert K3 IF signal to I/Q signals. I have this setup and it works fine, without any images. The fact that you have images usually indication that one of the signals (I or Q) is not reaching your sound card. Y our sound card shall have stereo input with good separation of the channels for this to work. Most built in laptop sound cards will not work because they have mono input. For "on par" performance you need one of the expensive sound cards with conversion rate of 200 kHz or near of . E-MU brand comes to mind but there are others. Like SDR, P3 also converts the IF signal to I/Q, but does it digitally, so these signals are not available to outside world. P3, at least in it's current design, cannot accept externally generated I/Q signals either. Since the KX3 by nature is SDR, the output of it is the IQ signals and so P3 cannot be used with it. 73, Igor, N1YX ----- Original Message ----- From: "Richard Fjeld" <[hidden email]> To: "elecraft posting" <[hidden email]> Sent: Monday, November 14, 2011 1:49:59 AM Subject: [Elecraft] SDR-IF and I/Q questions I didn't get any responses to my questions asking for info about those who were successfully running SDR-IF software on a par with a P3, or from those who were not successful. I did not find any ground loops in my system, and I still do not know why some SDR-IF programs run with mirrored images and a few do not. IMHO, those that do not have mirrored images with my computer, are not on par with a P3. So, I am moving on to other things. I have decided that, at my age, life is too short for SDR. I am greatly disappointed to learn that the KX3 will not accept a P3. Richard Fjeld, n0ce [hidden email] I'd rather be learning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] 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:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Richard Fjeld
The thread title didn't say anything about being restricted to the KX3, and your comment simply stated that you were giving up on SDR in general ... hence my comment. Whatever rig you've been having your problems with (I assume a K3), it certainly wasn't a KX3. I'm curious which programs you have tried that didn't have good rig control. Do you include TRX-Pan and NaP3 in that group? I'm interested because those are the programs I intend to try with my K3. By the way, my intended use would be for spectrum display and point/click QSY. I'm perfectly happy to rely on the rig for actual reception, filtering, demodulation, gain control, etc. Your needs may be different than mine. Dave AB7E On 11/14/2011 11:42 AM, Richard Fjeld wrote: > Well Dave, maybe I am missing something here, but this thread has been > about the anticipated KX3 and having a Pan-Adapter to use with it. As I understand > it, the I/Q leads are being brought out, but not the IF. So other SDR receivers, or adapters, are not > needed. Therefore, we are down to finding acceptable software, soundcards, and computers > to make it work on a par with a P3. > > The programs I tried that are not producing mirrored images are lacking good control between radio and software. No 'search and pounce' capability, and time consuming to adjust as the frequency was changed beyond the display width. Not hardly on a par with a P3. Perhaps there is something out there that I am not aware of. I'll concede that, but if it is a commercial product, I want to exercise 'buyer beware'. > > I find PSDR-IF would be a very good match if it wasn't for the mirrored images that fills a crowded > screen. Thanks to a fine gentleman who sent me this link, it shows I am not the only one > having this problem. Go to: > http://groups.google.com/group/powersdr-if-stage/search?group=powersdr-if-stage&q=image&qt_g=Search+this+group > > > and click on the posts with "image" to see all the posts on this topic. Many people are having trouble > with it. AND, it pretty well identifies the problem. If it ever gets fixed, we will have something encouraging. At the speed it is going, it may be only for younger people. > 73, > Dick, n0ce > > _________________________________ > What specific shortfalls in SDR applications that don't have images lead > you to conclude they are inferior to the P3? > > Also, keep in mind that "SDR" is not completely defined by > soundcard-based configurations. Have you considered other > computer-based SDR front ends like SDR-IQ or QSR-1 before making such a > blanket assessment? > > Dave AB7E ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Gilbert
David
Space diversity with the K3 is an interesting idea. A variable phase shift could be achieved by adding the raw audio from main rx to a 90degree phase shifted version of itself. Adjusting the relative amplitude of the 90deg version will then vary the resultant phase. Is a phase shift at audio what's needed here, or is it a delay? I'll let others debate this! 73 Graham On 19:59, David Gilbert wrote: > > John, do any of the SDR programs you mention allow you to monitor the > two audio outputs AFTER the inserted phase shift? > > Here's why I ask, although it is essentially unrelated to a normal SDR > application ... > > I'm convinced that we should be able to use the diversity feature of a > K3 with both receivers to spacially discriminate against an unwanted > signal. We should be able to do it in the horizontal plane by feeding > two vertical antennas into the K3, one into each receiver. We might > be able to partially do it in the vertical plane by, for example, > feeding two stacked antennas on the same tower into the K3 .... one > into each receiver. All we need is a variable phase shift in the > audio since phase is preserved in the conversion from RF to audio. > I've searched for normal audio processing software to accomplish this > (volume equalization, phase shift, inversion, sum), but so far haven't > found anything other than some extremely expensive professional audio > stuff for large auditoriums. > > I've always thought that something like this could be built into the > K3 internal software, maybe using the VFO B knob to adjust the phase. > The K3 phase lock in diversity mode is not determinant (the actual > phase is essentially random at any frequency) so the null would have > to be readjusted at each frequency, but I still think it would be a > neat capability. At one point (more than a year ago) Elecraft sounded > mildly intrigued by the idea when I first suggested it, but I don't > think they've spent any time on it. > > 73, > Dave AB7E Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by David Gilbert
Hi,
Lots of people, including myself are using NaP3 with the K3. I haven't seen an image for a very long time. The automatic image rejection algorithm is perhaps a little moody if there are next to no signals, which certainly hasn't been the case recently where it is the most useful, on 10m. The rig control is excellent. I believe most PSDR users have by now moved over to NaP3 which is much easier to set up and maintain (there is no "maintenance" like with PSDR which usually goes belly up once in a while and has to have at least its configuration files replaced). Knut
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In reply to this post by Richard Fjeld
Dick, if some programs work, then your levels may be low. PowerSDR/IF
and NaP3 use an algorithm developed by Flex Radio called WBIR (Wide Band Image Rejection). It does a phenomenal job of eliminating images (>80dB) but is sensitive to levels, requiring a minimum amount of total signal power in the display to work. Since you say that other programs work, your issue may be levels. Most SDR users have no trouble with this, but there are stubborn cases like yours that pop up. They are usually related to sound card drivers or other system settings... or even bad cables. I had one customer who sent me his whole setup, and I found that his new cables from Radio Shack had about 10 ohms resistance between center pin and shield. There are tens of thousands of SDR users out there who are successfully using them, so these things can be solved. Pete and I have been talking about an indicator for NaP3 that would graphically display the overall balance of the sound card channels as a way to verify that the channels are matched within the range necessary for WBIR to work, but this would take some thought... and work. It would be worthwhile, though, for the percentage of users with stubborn image issues. One very simple program, that provides all the features of the P3 except "fixed tune" mode, is TRX-Pan. It is extremely well integrated with the K3, and has a very simple manual image rejection adjustment (sliders for gain and phase). You set it once and forget it. There is no automatic "learning" needed and it will not change with levels or time. The tradeoff is that image rejection across the display will vary from about 60-80dB. Only the very strongest signal (S9+30dB or more) would produce an image, and it would be 60-80dB weaker than the signal. Since the adjustment is manual, you can easily tell if your sound card has a problem, and make external adjustments while watching the image for changes. TRX-Pan requires LP-Bridge or TRX-Manager as the link between the rig and software. It is very easy to set up, especially with LP-Bridge. Everything you need can be found here... http://www.telepostinc.com/TRXP.html 73, Larry N8LP On 11/15/2011 3:53 AM, [hidden email] wrote: > Date: Mon, 14 Nov 2011 12:42:41 -0600 > From: "Richard Fjeld"<[hidden email]> > Subject: [Elecraft] SDR-IF and I/Q questions > To: "elecraft posting"<[hidden email]> > Message-ID:<20779EE975F7478494FA31FC637B8D30@BIOSTAR> > Content-Type: text/plain; charset="Windows-1252" > > Well Dave, maybe I am missing something here, but this thread has been > about the anticipated KX3 and having a Pan-Adapter to use with it. As I understand > it, the I/Q leads are being brought out, but not the IF. So other SDR receivers, or adapters, are not > needed. Therefore, we are down to finding acceptable software, soundcards, and computers > to make it work on a par with a P3. > > The programs I tried that are not producing mirrored images are lacking good control between radio and software. No 'search and pounce' capability, and time consuming to adjust as the frequency was changed beyond the display width. Not hardly on a par with a P3. Perhaps there is something out there that I am not aware of. I'll concede that, but if it is a commercial product, I want to exercise 'buyer beware'. > > I find PSDR-IF would be a very good match if it wasn't for the mirrored images that fills a crowded > screen. Thanks to a fine gentleman who sent me this link, it shows I am not the only one > having this problem. Go to: > http://groups.google.com/group/powersdr-if-stage/search?group=powersdr-if-stage&q=image&qt_g=Search+this+group > > > and click on the posts with "image" to see all the posts on this topic. Many people are having trouble > with it. AND, it pretty well identifies the problem. If it ever gets fixed, we will have something encouraging. At the speed it is going, it may be only for younger people. > 73, > Dick, n0ce ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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