[Flexradio] 144-28FRS Problem
I apologise in advance for this posting, and realise I should wait until tomorrow to discuss with the supplier, but my impatience to get going got the better of me! I took delivery of a SDR-1000 (1 watt version) a few days ago and am up and running on HF. The suppliers (Waters and Stanton - who have given excellent service) installed the 144-28FRS. I can not hear anything through it, or get any 144MHz RF out of it. I appreciate that a likely possibility is that I am doing something wrong, but can't see what that is. I will check with WS tomorrow that they tested it live before dispatch, and just possibly there is a hardware problem. On Set-up I've told it that the transverter is installed. On XVTRs I have enabled the first line, UCB 0, Button text 144, LO offset 116.0, LO error 0, Begin Freq 144, End Freq 146, Rx gain 0. When I transmit the signal meter says there is power output, but there is nothing on 144MHz - but there is output at 28MHz on the appropriate frequency from the QRP socket. I am using the Parallel-USB converter. Many thanks David, G4YTL ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] Filter measurements
All Here are some filter measurements I did with the Flex-Radio. I'd be interested in anyone else's numbers if there are differences - there may be some configuration or setup option that I've overlooked that would affect the results. FYI, I'm interested in cases where someone has come up with different results and has some ideas as to why they're different (as opposed to theoretical or hypothetical suggestions without any any substantiating measurements...) I should have been from Missouri. Also, I am interested in knowing if the shape factor is designed to be wider with narrow filters and get tighter as the filter bandwidth increases (or if this is an artifact of my measurements, physics, etc.) I've seen that steep skirts on analog filters cause ringing, but that this can be avoided with DSP filters. If this is the case, why not use arbitrarily steep filters? Is it a computational cost issue, or are there other tradeoffs that make this impractical. This isn't a criticism; I'd just like to know how it works. Thanks again to all the suggestions and discussion - I've learned a lot from you guys, and I really appreciate it! Mark Here are (I think) the salient features of my setup and the test conditions: - PowerSDR v1.9.0 SVN 899 - Edirol FA-66 - 48000 Ks/s - Buffer 2048 - 4096 FFT Bins - Hanning window - AGC off (it didn't seem to make any difference - I assume the S-Meter is before the AGC.) I used an HP 10811 OCXO as the oscillator at 10MHz because it's the cleanest, most stable oscillator I have. Before the test I ran the receive image rejection calibration and calibrated the S-meter with a 50uV and a 1uV signal to get it as accurate as possible. I tuned the receiver up and down in 1 Hz increments and measured the signal level as reported by the Flex S-meter - to the nearest 10th of a dBm. When I finished the series, I repeated the 10Hz and 20Hz filter tests just to see if anything had drifted or changed. The results were the same. Here are the results: 10Hz filter -6dB 32Hz wide -60dB 89Hz wide 2.78 shape factor 20Hz filter -6dB 34Hz wide -60dB 95Hz wide 2.76 shape factor 30Hz filter -6dB 38Hz wide -60dB 102Hz wide 2.68 shape factor 50Hz filter -6dB 51Hz wide -60dB 122Hz wide 2.39 shape factor 100Hz filter -6dB 100Hz wide -60dB 172Hz wide 1.72 shape factor 200Hz filter -6dB 200Hz wide -60dB 272Hz wide 1.36 shape factor 250Hz filter -6dB 250Hz wide -60dB 322Hz wide 1.29 shape factor 500Hz filter -6dB 500Hz wide -60dB 574Hz wide 1.15 shape factor 600Hz filter -6dB 600Hz wide -60dB 674Hz wide 1.12 shape factor 1000Hz filter -6dB 1000Hz wide -60dB 1074Hz wide 1.07 shape factor 2400Hz filter -6dB 2400Hz wide -60dB 2474Hz wide 1.03 shape factor So the filter algorithm is more accurate above 30Hz or so. I suspect that there are rounding errors and other issues that keep them from measuring accurately down below 30Hz. Mark -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/8fc5a6c0/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] 144-28FRS - problem solved
Sorry for the bandwidth - problem solved! It was a hardware fault - a duff power connection to the transverter board. Now all functioning Ok. 73 David, G4YTL ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
Mark, Nice piece of work. This series of measurements is a good illustration of the effects of the size of the DSP buffer. Did you run the test with the DSP buffer set at 4096? I always run my DSP buffer at 4096, and get basically the result that the 25 Hz filter is 25 Hz at -6dB with a 48Ks/s rate. I get results similar to yours running my FireBox at 96000s/s with the 4096 Buffer or when using the 2048 DSP buffer and sampling at 48Ks/s, but a little wider. My results show the 25 Hz filter to be approximately 50 Hz wide when sampling at 48Ks/s and using a 2048 DSP buffer. The math of the shape 6/60 dB shape factor will normally cause the wider filter to have a smaller shape factor, with the same filter roll off. You might want to look at the enhancement list. I submitted an enhancement this morning to add 8192 and 16348 DSP buffers to improve the filter shape factor when sampling at 96K and 192K s/s. At 08:01 AM 2/18/2007, Mark Amos wrote: All Here are some filter measurements I did with the Flex-Radio. I'd be interested in anyone else's numbers if there are differences - there may be some configuration or setup option that I've overlooked that would affect the results. FYI, I'm interested in cases where someone has come up with different results and has some ideas as to why they're different (as opposed to theoretical or hypothetical suggestions without any any substantiating measurements...) I should have been from Missouri. Also, I am interested in knowing if the shape factor is designed to be wider with narrow filters and get tighter as the filter bandwidth increases (or if this is an artifact of my measurements, physics, etc.) I've seen that steep skirts on analog filters cause ringing, but that this can be avoided with DSP filters. If this is the case, why not use arbitrarily steep filters? Is it a computational cost issue, or are there other tradeoffs that make this impractical. This isn't a criticism; I'd just like to know how it works. Thanks again to all the suggestions and discussion - I've learned a lot from you guys, and I really appreciate it! Mark Here are (I think) the salient features of my setup and the test conditions: - PowerSDR v1.9.0 SVN 899 - Edirol FA-66 - 48000 Ks/s - Buffer 2048 - 4096 FFT Bins - Hanning window - AGC off (it didn't seem to make any difference - I assume the S-Meter is before the AGC.) I used an HP 10811 OCXO as the oscillator at 10MHz because it's the cleanest, most stable oscillator I have. Before the test I ran the receive image rejection calibration and calibrated the S-meter with a 50uV and a 1uV signal to get it as accurate as possible. I tuned the receiver up and down in 1 Hz increments and measured the signal level as reported by the Flex S-meter - to the nearest 10th of a dBm. When I finished the series, I repeated the 10Hz and 20Hz filter tests just to see if anything had drifted or changed. The results were the same. Here are the results: 10Hz filter -6dB 32Hz wide -60dB 89Hz wide 2.78 shape factor 20Hz filter -6dB 34Hz wide -60dB 95Hz wide 2.76 shape factor 30Hz filter -6dB 38Hz wide -60dB 102Hz wide 2.68 shape factor 50Hz filter -6dB 51Hz wide -60dB 122Hz wide 2.39 shape factor 100Hz filter -6dB 100Hz wide -60dB 172Hz wide 1.72 shape factor 200Hz filter -6dB 200Hz wide -60dB 272Hz wide 1.36 shape factor 250Hz filter -6dB 250Hz wide -60dB 322Hz wide 1.29 shape factor 500Hz filter -6dB 500Hz wide -60dB 574Hz wide 1.15 shape factor 600Hz filter -6dB 600Hz wide -60dB 674Hz wide 1.12 shape factor 1000Hz filter -6dB 1000Hz wide -60dB 1074Hz wide 1.07 shape factor 2400Hz filter -6dB 2400Hz wide -60dB 2474Hz wide 1.03 shape factor So the filter algorithm is more accurate above 30Hz or so. I suspect that there are rounding errors and other issues that keep them from measuring accurately down below 30Hz. Mark xRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Poor Man's Universal Controller Board (PMUCB) available assembled, as a kit of parts, or the bare PCB
I use it for PTT and Amp Key... Does anyone know if it will handle and old SB-201 keying circuit? steve kw5tx Larry Loen wrote: I have also used this board. I haven't used all of the options on it, but I have already gotten great value from it. Great for HFers. Larry WO0Z Mike Naruta wrote: Wally, I really like the Poor Man's UCB that I received from you. It it a very nice solution for connecting to the SDR-1000. What a value. A good quality board and assembled for the cost of taking my spouse out to a restaurant! Mike - AA8K Wallace Watson wrote: Greetings Flex'ers, I have a quantity of Poor Man's UCB's available for purchase. Please let me know if you have an interest in obtaining an assembled board, a complete kit of parts, or a bare printed circuit board? ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
I'm not a dsp guru, but I think what you're seeing at the smaller filter sizes is an artifact of spectrum leakage (http://www.dsptutor.freeuk.com/analyser/guidance.html#leakage) from one bin to another.The basic FFT bin size is 11hz, so for a filter 30 hz or below you've only got 3 bins to work with so I think the effects of leakage will be relatively larger than with larger filters since the transition zones cover more bins. I'd think to improve this one would need to band pass filter the signal of interest, then decimate and do an FFT of the decimated signal such that you have a smaller bin width. Might be an interesting hack to try when the passband is small. Regards, Bill (kd5tfd) At 07:01 AM 2/18/2007, Mark Amos wrote: All Here are some filter measurements I did with the Flex-Radio. I'd be interested in anyone else's numbers if there are differences - there may be some configuration or setup option Also, I am interested in knowing if the shape factor is designed to be wider with narrow filters and get tighter as the filter bandwidth increases (or if this is an artifact of my measurements, physics, etc.) I've seen that steep skirts on analog filters cause ringing, but that this can be avoided with DSP filters. If this is the case, why not use arbitrarily steep filters? Is it a computational cost issue, or are there other tradeoffs that make this impractical. This isn't a criticism; I'd just like to know how it works. Thanks again to all the suggestions and discussion - I've learned a lot from you guys, and I really appreciate it! Mark ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] Receiver sensitivity of the SDR1000
Hi. I am a complete newby to SDR, and am considering purchasing an SDR1000. When reading the specifications, I have noticed that the MDS is -130 dBM, which seems to pale in comparison to other popular rigs such as the IC756proIII, Orion2 and K2. For anyone who has used these other rigs, do the numbers translate into a real disadvantage in sensitivity, or they just numbers? Also- is receiver MDS something that can be improved with later editions of software? Many thanks and 73 Steve WA2DTW No need to miss a message. Get email on-the-go with Yahoo! Mail for Mobile. Get started. http://mobile.yahoo.com/mail -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/9fbe9c02/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
Mark and Bill, I made some measurements and got similar results as Mark. The one thing that confused me was the difference in shape factor between the narrow filters and the wide filters, but I think you just cleared that up for me, Bill. It has to be a function of the bin resolution and the bin bleed. Thanks, Mark for bringing this up, and thanks Bill for clearing my confusion...very interesting. Tom W0IVJ Bill Tracey wrote: I'm not a dsp guru, but I think what you're seeing at the smaller filter sizes is an artifact of spectrum leakage (http://www.dsptutor.freeuk.com/analyser/guidance.html#leakage) from one bin to another.The basic FFT bin size is 11hz, so for a filter 30 hz or below you've only got 3 bins to work with so I think the effects of leakage will be relatively larger than with larger filters since the transition zones cover more bins. I'd think to improve this one would need to band pass filter the signal of interest, then decimate and do an FFT of the decimated signal such that you have a smaller bin width. Might be an interesting hack to try when the passband is small. Regards, Bill (kd5tfd) At 07:01 AM 2/18/2007, Mark Amos wrote: All Here are some filter measurements I did with the Flex-Radio. I'd be interested in anyone else's numbers if there are differences - there may be some configuration or setup option Also, I am interested in knowing if the shape factor is designed to be wider with narrow filters and get tighter as the filter bandwidth increases (or if this is an artifact of my measurements, physics, etc.) I've seen that steep skirts on analog filters cause ringing, but that this can be avoided with DSP filters. If this is the case, why not use arbitrarily steep filters? Is it a computational cost issue, or are there other tradeoffs that make this impractical. This isn't a criticism; I'd just like to know how it works. Thanks again to all the suggestions and discussion - I've learned a lot from you guys, and I really appreciate it! Mark ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/19eea4ab/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] USB Problem update
I was having a serious problem with the USB adaptor disconnecting on a frequent basis. I followed everyone's suggestions for a fix and still the problem continued. My new dedicated Dell didn't have a parallel port, so I ordered a PCI/parallel card. After installing that and using the cable supplied by Flex, the problem completely went away and has been working beautifully. I even purchased a power hub for the USB. Still don't know why, but I'm happy to be fixed. Phil Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com http://www.instantgourmetspices.com/ www.W9DVM.com http://www.w9dvm.com/ 727-944-3226 800-395-7795 pin 02 FAX 727-937-8834 NASFT # 30210 W9DVM ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
On 18/02/07, Bill Tracey [EMAIL PROTECTED] wrote: The basic FFT bin size is 11hz, so for a filter 30 hz or Bill, That is a minor difference, but anyhow, I have a question just for understanding better: If the sampling frequency is 48 kHz and the number of bins is 4096, would the bin be 48000/4096 Hz = 11.72 Hz wide and consequently 44100/4096 Hz = 10.77 Hz wide with 44.1 kHz sampling? Please advice so that I can use correct numbers in my calculations. 73, Ahti OH2RZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] DJ2HZ silent key
Dear SDR-Friends, I am sorry to announce that Werner (Ron), DJ2HZ, passed away in November 2006 after fighting hard against a severe disease. Ron had been a member of the German SDR group since December 2005. Often he took part during our Sunday SDR-meetings on 80m with his outstanding signal in quality and strength. During an exhibition in Hannover I had the privilege to meet Ron a few weeks before he died. Ron showed an impressive attitude regarding his fate. We are missing Ron! Klaus, DK7XL -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/b19cb89c/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
At 08:18 AM 2/18/2007, Tom Thompson wrote: Mark and Bill, I made some measurements and got similar results as Mark. The one thing that confused me was the difference in shape factor between the narrow filters and the wide filters, but I think you just cleared that up for me, Bill. It has to be a function of the bin resolution and the bin bleed. Thanks, Mark for bringing this up, and thanks Bill for clearing my confusion...very interesting. This is somewhat confusing because you are using a conceptual model (shape factor) that is really derived from analog filter design in a domain (digital filters with a lot of samples) that it isn't as well suited to. In analog filters, we talk about how many sections or poles it might have, and knowing that number tells you what the ultimate rolloff is going to be (12 dB/octave per section, eh?). The close in rolloff in a high q filter (say a crystal lattice) is still determined by combining a relatively small number of tuned circuits (albeit high q ones).. Essentially, you stack up a bunch of stagger tuned sections so that you get a bart's head type frequency domain response. You have to worry about interacctions between the tuned circuits (some deliberate, as in a double tuned IF stage, some not), drifting in component parameters, and non-ideal components, so Q isn't infinite. But in the digital domain, you can (easily) build a filter that is the equivalent of 4000 ideal lossless LC tuned networks with infinite Q. Yowza!.. Sure, there are tradeoffs, and there are some peculiarities (roundoff, truncation, etc.) but it's easy to build filters that have desirable properties but which don't fit the usual analog filter metrics and design tradeoffs. For instance, it's pretty easy to build a linear phase filter in the digital world (one that has the same time delay for all frequencies in the passband, which has minimal pulse shape distortion).. something that is quite challenging with analog filters (as anyone who has agonized over group delay properties has dealt with). In the digital world, one could build a dynamically adjusting CW keying envelope that is precisely limited in it's bandwidth to the current keying rate, without ringing. Heck, in the digital world, one can have non-physically realizable filters (i.e. that have an output before the input is applied, in some senses) So the challenge we all face when working with digital filters is that a lot of the traditional measurements and tradeoffs change. Sometimes, a measurement (e.g. swept response) gives results that, if an analog filter were being measured, would mean that the measurement system is broken. Other times, we make measurements that mean something in terms of an analog design (3rd order intercept is a good example) that doesn't necessarily have the same interpretation in the digital world (or more correctly in the hybrid digital analog world). For instance, Spurious Free Dynamic Range is a very different thing when applied to A/Ds than when applied to a LNA and mixer. Shape Factor for filters is another such metric.. It's a shorthand way of describing a certain kind of filter (bandpass with symmetric skirts). A shape factor of 6 is a lot different from 2, but the difference between 1.1 and 1.05 is less so, in terms of practical significance. if you really want to specify adjacent channel rejection, then that's the spec you should be working with (i.e. 3dB bandwidth of X kHz, 60 dB down at X+Y kHz) Also, watch out for stopband bounce.. I work with a variety of analog filters that have fairly steep rolloffs, a deep null at about 2.5-3x cutoff frequency, but that only have 30 dB of rejection far out. Why? Because other stages provide the far away attenuation, but I'm concerned about suppressing the spur at the clock rate from the glitch energy in the dac. The filter might have a fair amount of phase ripple in the passband, but I can compensate that in the equalization in the digital data stream going to the DAC. But, if I were to look at just the digital filter characteristics, it would look terrible. It's the overall system performance that you're concerned about. A similar strategy is used in consumer audio DACs. They take the digital stream at 44.1 kS/s, interpolate it it up to 192k, then run it to the DAC. The analog filter can then use relatively few sections with low Q, because the 192 is almost 10 times the filter cutoff of 20-25 kHz, so you don't need an extreme shape factor to get good performance. Jim, W6RMK ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
I am interested in using my SDR with a new Dell latop that does not have a parallel port and was considering the USB cable sold by Flex. If there are problems with the USB port, is there another way to create a parallel port on a laptop that has none? PCMCIA card? Other? Gary AI4IN -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil LaMarche Sent: Sunday, February 18, 2007 11:35 AM To: Flexradio@flex-radio.biz Subject: [Flexradio] USB Problem update I was having a serious problem with the USB adaptor disconnecting on a frequent basis. I followed everyone's suggestions for a fix and still the problem continued. My new dedicated Dell didn't have a parallel port, so I ordered a PCI/parallel card. After installing that and using the cable supplied by Flex, the problem completely went away and has been working beautifully. I even purchased a power hub for the USB. Still don't know why, but I'm happy to be fixed. Phil Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com http://www.instantgourmetspices.com/ www.W9DVM.com http://www.w9dvm.com/ 727-944-3226 800-395-7795 pin 02 FAX 727-937-8834 NASFT # 30210 W9DVM ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
Gary, there are hundreds of SDR-1000 + USB owners who are very happy with the USB Converter connection. Ahti and Sami designed a quality device that works well for many of us. There certainly is a problem with many desktops and laptops that under power the USB port. USB ports should supply up to 500ma but many do not. - If you are adept at using the Device Manager, you can examine your Root USB Hub Properties to see the POWER being drawn by any particular USB device. Mine shows FlexRadio SDR-1000 USB Adapter 100ma. My darn Intel Webcam shows 500ma! There are many USB monitoring utilities. Here is one from M$ http://support.microsoft.com/kb/838100 (usbview.exe) It is a shame that so many good USB products are corrupted by noisy PC Power supplies and cheaply designed consumer mother boards. - Customer Support calls to Flex often include problems with PC ground loops, low voltage or noisy parallel, serial, and USB ports, insufficient P/S wattage for all the PCIe cards plugged in and so on. You would be amazed at the current drawn by 1GB of DDR2 RAM !! Be sure your P/S is up to the task. Many small desktop systems are sold with 150W (or even smaller) power supplies that are poorly regulated in their design to meet cost cutting objectives. Those P/S won't properly power a motherboard loaded with RAM and plug in cards. - There was a discussion about laptops last week. Dudley WA5QPZ summarized the Laptop design in this way: Disks are slower Memory is slower CPUs generally do not have as much cache memory I/O buses are slower Running more processes in background (things like battery power management) Graphics are slower (have to conserve power) None of those factors are in our favor when we want an optimized system for SDR Console work. - Ken Gary Strong wrote: I am interested in using my SDR with a new Dell latop that does not have a parallel port and was considering the USB cable sold by Flex. If there are problems with the USB port, is there another way to create a parallel port on a laptop that has none? PCMCIA card? Other? Gary AI4IN -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil LaMarche Sent: Sunday, February 18, 2007 11:35 AM To: Flexradio@flex-radio.biz Subject: [Flexradio] USB Problem update I was having a serious problem with the USB adaptor disconnecting on a frequent basis. I followed everyone's suggestions for a fix and still the problem continued. My new dedicated Dell didn't have a parallel port, so I ordered a PCI/parallel card. After installing that and using the cable supplied by Flex, the problem completely went away and has been working beautifully. I even purchased a power hub for the USB. Still don't know why, but I'm happy to be fixed. Phil Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com http://www.instantgourmetspices.com/ www.W9DVM.com http://www.w9dvm.com/ 727-944-3226 800-395-7795 pin 02 FAX 727-937-8834 NASFT # 30210 W9DVM ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
Not sure this is correct -- I suspect what it is telling you is what the device claims it needs, not what it is actually drawing. Regards, Bill At 01:24 PM 2/18/2007, Ken N9VV wrote: ... - If you are adept at using the Device Manager, you can examine your Root USB Hub Properties to see the POWER being drawn by any particular USB device. Mine shows FlexRadio SDR-1000 USB Adapter 100ma. My darn Intel Webcam shows 500ma! There are many USB monitoring utilities. Here is one from M$ http://support.microsoft.com/kb/838100 (usbview.exe) It is a shame that so many good USB products are corrupted by noisy PC Power supplies and cheaply designed consumer mother boards. ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
I am interested in using my SDR with a new Dell latop that does not have a parallel port and was considering the USB cable sold by Flex. If there are problems with the USB port, is there another way to create a parallel port on a laptop that has none? PCMCIA card? Other? Many laptops have BIOS or some other restriction that prevents them from using a PC card or PCMCIA module for a parallel port. My Dell laptops that lack parallel ports also will not recognize any of the three different PC card parallel port interfaces that I could find. It was an expen$ive lesson. If you want to add a parallel PC card-based interface to your laptop, try to get the supplier to either include it as an accessory at the time of order or accept the ability to operate with a card you specify as a condition of purchase. Otherwise, try to verify the particular laptop model you intend to purchase with the PC card supplier before you buy it. GL, Lyle KK7P ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
Think this is correct. The sampling rate determines how many Hz you can see and the FFT size determines how many bins those Hz are divided into. Bill (kd5tfd) At 11:08 AM 2/18/2007, Ahti Aintila wrote: On 18/02/07, Bill Tracey [EMAIL PROTECTED] wrote: The basic FFT bin size is 11hz, so for a filter 30 hz or Bill, That is a minor difference, but anyhow, I have a question just for understanding better: If the sampling frequency is 48 kHz and the number of bins is 4096, would the bin be 48000/4096 Hz = 11.72 Hz wide and consequently 44100/4096 Hz = 10.77 Hz wide with 44.1 kHz sampling? Please advice so that I can use correct numbers in my calculations. 73, Ahti OH2RZ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
You may also envisage the use of a port replicator. It will give you serial, parallel, etc. 73 José F5JD Lyle Johnson a écrit : I am interested in using my SDR with a new Dell latop that does not have a parallel port and was considering the USB cable sold by Flex. If there are problems with the USB port, is there another way to create a parallel port on a laptop that has none? PCMCIA card? Other? Many laptops have BIOS or some other restriction that prevents them from using a PC card or PCMCIA module for a parallel port. My Dell laptops that lack parallel ports also will not recognize any of the three different PC card parallel port interfaces that I could find. It was an expen$ive lesson. If you want to add a parallel PC card-based interface to your laptop, try to get the supplier to either include it as an accessory at the time of order or accept the ability to operate with a card you specify as a condition of purchase. Otherwise, try to verify the particular laptop model you intend to purchase with the PC card supplier before you buy it. GL, Lyle KK7P ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] 144-28FRS - problem solved
David, Glad that you got it figured out. For the record, you will want to use either the Setup Form XVTR Present checkbox OR the XVTR Form setup, but not both as this will cause considerable confusion for the software. Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] radio.biz] On Behalf Of David Hilton-Jones Sent: Sunday, February 18, 2007 7:08 AM To: flexradio Subject: [Flexradio] 144-28FRS - problem solved Sorry for the bandwidth - problem solved! It was a hardware fault - a duff power connection to the transverter board. Now all functioning Ok. 73 David, G4YTL ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
I wonder how the polyphase option would affect these measurements... Eric Wachsmann FlexRadio Systems -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] radio.biz] On Behalf Of Mark Amos Sent: Sunday, February 18, 2007 7:02 AM To: flexradio@flex-radio.biz Subject: [Flexradio] Filter measurements All Here are some filter measurements I did with the Flex-Radio. I'd be interested in anyone else's numbers if there are differences - there may be some configuration or setup option that I've overlooked that would affect the results. FYI, I'm interested in cases where someone has come up with different results and has some ideas as to why they're different (as opposed to theoretical or hypothetical suggestions without any any substantiating measurements...) I should have been from Missouri. Also, I am interested in knowing if the shape factor is designed to be wider with narrow filters and get tighter as the filter bandwidth increases (or if this is an artifact of my measurements, physics, etc.) I've seen that steep skirts on analog filters cause ringing, but that this can be avoided with DSP filters. If this is the case, why not use arbitrarily steep filters? Is it a computational cost issue, or are there other tradeoffs that make this impractical. This isn't a criticism; I'd just like to know how it works. Thanks again to all the suggestions and discussion - I've learned a lot from you guys, and I really appreciate it! Mark Here are (I think) the salient features of my setup and the test conditions: - PowerSDR v1.9.0 SVN 899 - Edirol FA-66 - 48000 Ks/s - Buffer 2048 - 4096 FFT Bins - Hanning window - AGC off (it didn't seem to make any difference - I assume the S-Meter is before the AGC.) I used an HP 10811 OCXO as the oscillator at 10MHz because it's the cleanest, most stable oscillator I have. Before the test I ran the receive image rejection calibration and calibrated the S-meter with a 50uV and a 1uV signal to get it as accurate as possible. I tuned the receiver up and down in 1 Hz increments and measured the signal level as reported by the Flex S-meter - to the nearest 10th of a dBm. When I finished the series, I repeated the 10Hz and 20Hz filter tests just to see if anything had drifted or changed. The results were the same. Here are the results: 10Hz filter -6dB 32Hz wide -60dB 89Hz wide 2.78 shape factor 20Hz filter -6dB 34Hz wide -60dB 95Hz wide 2.76 shape factor 30Hz filter -6dB 38Hz wide -60dB 102Hz wide 2.68 shape factor 50Hz filter -6dB 51Hz wide -60dB 122Hz wide 2.39 shape factor 100Hz filter -6dB 100Hz wide -60dB 172Hz wide 1.72 shape factor 200Hz filter -6dB 200Hz wide -60dB 272Hz wide 1.36 shape factor 250Hz filter -6dB 250Hz wide -60dB 322Hz wide 1.29 shape factor 500Hz filter -6dB 500Hz wide -60dB 574Hz wide 1.15 shape factor 600Hz filter -6dB 600Hz wide -60dB 674Hz wide 1.12 shape factor 1000Hz filter -6dB 1000Hz wide -60dB 1074Hz wide 1.07 shape factor 2400Hz filter -6dB 2400Hz wide -60dB 2474Hz wide 1.03 shape factor So the filter algorithm is more accurate above 30Hz or so. I suspect that there are rounding errors and other issues that keep them from measuring accurately down below 30Hz. Mark -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex- radio.biz/attachments/20070218/8fc5a6c0/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] Filters redux.
with digital filters is that a lot of the traditional measurements and tradeoffs change.Sometimes, a measurement (e.g. swept response) gives results that, if an analog filter were being measured, would mean that the measurement system is broken. Other times, we make measurements that mean something in terms of an analog design (3rd order intercept is a good example) that doesn't necessarily have the same interpretation in the digital world (or more correctly in the hybrid digital analog world).For instance, Spurious Free Dynamic Range is a very different thing when applied to A/Ds than when applied to a LNA and mixer. Shape Factor for filters is another such metric.. It's a shorthand way of describing a certain kind of filter (bandpass with symmetric skirts).A shape factor of 6 is a lot different from 2, but the difference between 1.1 and 1.05 is less so, in terms of practical significance.if you really want to specify adjacent channel rejection, then that's the spec you should be working with (i.e. 3dB bandwidth of X kHz, 60 dB down at X+Y kHz) Also, watch out for stopband bounce.. I work with a variety of analog filters that have fairly steep rolloffs, a deep null at about 2.5-3x cutoff frequency, but that only have 30 dB of rejection far out.Why?Because other stages provide the far away attenuation, but I'm concerned about suppressing the spur at the clock rate from the glitch energy in the dac.The filter might have a fair amount of phase ripple in the passband, but I can compensate that in the equalization in the digital data stream going to the DAC.But, if I were to look at just the digital filter characteristics, it would look terrible.It's the overall system performance that you're concerned about. A similar strategy is used in consumer audio DACs.They take the digital stream at 44.1 kS/s, interpolate it it up to 192k, then run it to the DAC.The analog filter can then use relatively few sections with low Q, because the 192 is almost 10 times the filter cutoff of 20-25 kHz, so you don't need an extreme shape factor to get good performance. Jim, W6RMK -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/04ee44f3/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] USB Problem update
Some USB's are more equal than others... The USB Farm ;-) 73 groeten Peter petervn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)gmail.com ; pa0pvn(a)amsat.org . Van: [EMAIL PROTECTED] namens Phil LaMarche Verzonden: zo 18-2-2007 17:35 Aan: Flexradio@flex-radio.biz Onderwerp: [Flexradio] USB Problem update I was having a serious problem with the USB adaptor disconnecting on a frequent basis. I followed everyone's suggestions for a fix and still the problem continued. My new dedicated Dell didn't have a parallel port, so I ordered a PCI/parallel card. After installing that and using the cable supplied by Flex, the problem completely went away and has been working beautifully. I even purchased a power hub for the USB. Still don't know why, but I'm happy to be fixed. Phil ---snip--- -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/1a5b4226/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Take care!! USB Problem update
As far as I am aware Not all printer ports on USB or PCI to printer port adapters/converters are created equal either. Do not ask me about Brands or types, do not know the (American) market. 73 peter pa0pvn groeten Peter petervn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)gmail.com ; pa0pvn(a)amsat.org . Van: [EMAIL PROTECTED] namens [EMAIL PROTECTED] Verzonden: zo 18-2-2007 23:28 Aan: Phil LaMarche; Flexradio@flex-radio.biz Onderwerp: Re: [Flexradio] USB Problem update Some USB's are more equal than others... The USB Farm ;-) 73 groeten Peter petervn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)hetnet.nl mailto:[EMAIL PROTECTED] ; pa0pvn(a)gmail.com ; pa0pvn(a)amsat.org . Van: [EMAIL PROTECTED] namens Phil LaMarche Verzonden: zo 18-2-2007 17:35 Aan: Flexradio@flex-radio.biz Onderwerp: [Flexradio] USB Problem update I was having a serious problem with the USB adaptor disconnecting on a frequent basis. I followed everyone's suggestions for a fix and still the problem continued. My new dedicated Dell didn't have a parallel port, so I ordered a PCI/parallel card. After installing that and using the cable supplied by Flex, the problem completely went away and has been working beautifully. I even purchased a power hub for the USB. Still don't know why, but I'm happy to be fixed. Phil ---snip--- -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070218/1a5b4226/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ -- next part -- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20070219/4711a3c5/attachment.html ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
[Flexradio] steady improvement
Hi, I have my SDR-1000 (1W version) working on all HF bands on RTTY and PSK (my favourite modes) using Virtual Comports, Virtual Audio Cables, and Mix-W with complete reliability. This setup in turn drives an all-band tube linear amplifier with (15-20 milliwatts) which in turn delivers a cool 20-50 watts of power to my antenna. I am using a small intermediate PC type relay in the SDR-1000 to key the clunkier relays in the linear (I intend to replace these one of these days) and all relays are paralleled with appropriate diodes to prevent voltage 'clicks'. I don't mind the audible clunks after all I know they are working hi. But I notice that on the waterfall tuner on MixW that when the transmission drops off and receive comes on there is a visible 'click' on the waterfall. There is no problem with the waterfall or system stablility ... just a 'click' . Any suggestions on where to look and what solutions may be possible to 'soften' the 'click' on the 'waterfall' during transition from transmit to receive. It almost sounds/looks like an RF click now I feed the system into an excellent antenna with little or no SWR which is up on a tower well away from the operating position. The amplifier is well shielded and is completely stable and i am using the time delay built into the X2 external switch. It is like the relays themselves are causing the click. I would expect the waterfall to stop when the system goes to transmit and start again when it goes to receive and there would be a nice clean break at both ends without that little 'flash' on the screen when it comes back on. It seems to me that the SDR, Linear, Software, Computer, and interconnections are involved in the switching process. Oh well maybe i am just a perfectionist to me Ham Radio should be split 50/50 between the operating position and the work bench hi. Any suggestions on where to look would be welcome. Jim, VE3CI ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] steady improvement
Jim, Do you hear the clicks if you are listening with another receiver? I am wondering if it is exclusively in the audio chain or if it is making to RF. -Tim, W4TME -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Dunstan Sent: Sunday, February 18, 2007 7:32 PM To: flexradio@flex-radio.biz Subject: [Flexradio] steady improvement Hi, I have my SDR-1000 (1W version) working on all HF bands on RTTY and PSK (my favourite modes) using Virtual Comports, Virtual Audio Cables, and Mix-W with complete reliability. This setup in turn drives an all-band tube linear amplifier with (15-20 milliwatts) which in turn delivers a cool 20-50 watts of power to my antenna. I am using a small intermediate PC type relay in the SDR-1000 to key the clunkier relays in the linear (I intend to replace these one of these days) and all relays are paralleled with appropriate diodes to prevent voltage 'clicks'. I don't mind the audible clunks after all I know they are working hi. But I notice that on the waterfall tuner on MixW that when the transmission drops off and receive comes on there is a visible 'click' on the waterfall. There is no problem with the waterfall or system stablility ... just a 'click' . Any suggestions on where to look and what solutions may be possible to 'soften' the 'click' on the 'waterfall' during transition from transmit to receive. It almost sounds/looks like an RF click now I feed the system into an excellent antenna with little or no SWR which is up on a tower well away from the operating position. The amplifier is well shielded and is completely stable and i am using the time delay built into the X2 external switch. It is like the relays themselves are causing the click. I would expect the waterfall to stop when the system goes to transmit and start again when it goes to receive and there would be a nice clean break at both ends without that little 'flash' on the screen when it comes back on. It seems to me that the SDR, Linear, Software, Computer, and interconnections are involved in the switching process. Oh well maybe i am just a perfectionist to me Ham Radio should be split 50/50 between the operating position and the work bench hi. Any suggestions on where to look would be welcome. Jim, VE3CI ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] steady improvement
Hi Jim, I use my SDR-1000 (with PA) on digi modes and CW just as you do. Here is my setup. I discovered that buffers are all critically important when trying to get the shortest T/R time (and consequently the smallest disturbance on the waterfall. You didn't mention your audio system, but I will assume it is the Delta-44. Set your hardware DMA buffers to 128 or 64 if you can. Set your PowerSDR AUDIO and DSP buffers to 512 or lower if you can get away with it. If you are using ASIO4ALL and some other sound system, turn the double buffering off. As for AGC, I keep it as l-o-n-g as possible so that it will glide through the T/R transition. I quickly learned that in order to copy Digital SSTV I had to set my PowerSDR console VAC sample rate to 48000, but my actual VAC speeds are all 11025=low and 48000=high with BPS low=8 and high=24. The Stream Format Limit is Cable Format. I haven't tried to transmit yet. I am still very confused about all the SSTV acronyms and jargon. It all works like magic with Phil N8VB vCOM 2.26 and CAT from MixW. I am very pleased with the setup and totally amazed how far the PowerSDR and associated third party code has come in such a short time. GL and keep your info flowing along, see you on MFSK, Olivia, or PSK31/63 ;-) 72/73 de ken n9vv Jim Dunstan wrote: Hi, I have my SDR-1000 (1W version) working on all HF bands on RTTY and PSK (my favourite modes) using Virtual Comports, Virtual Audio Cables, and Mix-W with complete reliability. This setup in turn drives an all-band tube linear amplifier with (15-20 milliwatts) which in turn delivers a cool 20-50 watts of power to my antenna. I am using a small intermediate PC type relay in the SDR-1000 to key the clunkier relays in the linear (I intend to replace these one of these days) and all relays are paralleled with appropriate diodes to prevent voltage 'clicks'. I don't mind the audible clunks after all I know they are working hi. But I notice that on the waterfall tuner on MixW that when the transmission drops off and receive comes on there is a visible 'click' on the waterfall. There is no problem with the waterfall or system stablility ... just a 'click' . Any suggestions on where to look and what solutions may be possible to 'soften' the 'click' on the 'waterfall' during transition from transmit to receive. It almost sounds/looks like an RF click now I feed the system into an excellent antenna with little or no SWR which is up on a tower well away from the operating position. The amplifier is well shielded and is completely stable and i am using the time delay built into the X2 external switch. It is like the relays themselves are causing the click. I would expect the waterfall to stop when the system goes to transmit and start again when it goes to receive and there would be a nice clean break at both ends without that little 'flash' on the screen when it comes back on. It seems to me that the SDR, Linear, Software, Computer, and interconnections are involved in the switching process. Oh well maybe i am just a perfectionist to me Ham Radio should be split 50/50 between the operating position and the work bench hi. Any suggestions on where to look would be welcome. Jim, VE3CI ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
Re: [Flexradio] Filter measurements
Jim, Maybe shape factor is the wrong term to use. All I know is that I took a relative low phase noise source, a HP 8640B, and tuned the SDR so that the signal was in the bandpass with the filter set to 1000 Hz. I then retuned the SDR so that the signal was 6db down. I then retuned the SDR again so that the signal was 60 db down. If I divided the 6 db bandpass by the 60 db bandpass, the number was about 1.1. If I followed the same proceedure with the filter set to 100 Hz , the number was 2.7. What causes the difference? Tom W0IVJ Jim Lux wrote: At 08:18 AM 2/18/2007, Tom Thompson wrote: Mark and Bill, I made some measurements and got similar results as Mark. The one thing that confused me was the difference in shape factor between the narrow filters and the wide filters, but I think you just cleared that up for me, Bill. It has to be a function of the bin resolution and the bin bleed. Thanks, Mark for bringing this up, and thanks Bill for clearing my confusion...very interesting. This is somewhat confusing because you are using a conceptual model (shape factor) that is really derived from analog filter design in a domain (digital filters with a lot of samples) that it isn't as well suited to. In analog filters, we talk about how many sections or poles it might have, and knowing that number tells you what the ultimate rolloff is going to be (12 dB/octave per section, eh?). The close in rolloff in a high q filter (say a crystal lattice) is still determined by combining a relatively small number of tuned circuits (albeit high q ones).. Essentially, you stack up a bunch of stagger tuned sections so that you get a bart's head type frequency domain response. You have to worry about interacctions between the tuned circuits (some deliberate, as in a double tuned IF stage, some not), drifting in component parameters, and non-ideal components, so Q isn't infinite. But in the digital domain, you can (easily) build a filter that is the equivalent of 4000 ideal lossless LC tuned networks with infinite Q. Yowza!.. Sure, there are tradeoffs, and there are some peculiarities (roundoff, truncation, etc.) but it's easy to build filters that have desirable properties but which don't fit the usual analog filter metrics and design tradeoffs. For instance, it's pretty easy to build a linear phase filter in the digital world (one that has the same time delay for all frequencies in the passband, which has minimal pulse shape distortion).. something that is quite challenging with analog filters (as anyone who has agonized over group delay properties has dealt with). In the digital world, one could build a dynamically adjusting CW keying envelope that is precisely limited in it's bandwidth to the current keying rate, without ringing. Heck, in the digital world, one can have non-physically realizable filters (i.e. that have an output before the input is applied, in some senses) So the challenge we all face when working with digital filters is that a lot of the traditional measurements and tradeoffs change. Sometimes, a measurement (e.g. swept response) gives results that, if an analog filter were being measured, would mean that the measurement system is broken. Other times, we make measurements that mean something in terms of an analog design (3rd order intercept is a good example) that doesn't necessarily have the same interpretation in the digital world (or more correctly in the hybrid digital analog world). For instance, Spurious Free Dynamic Range is a very different thing when applied to A/Ds than when applied to a LNA and mixer. Shape Factor for filters is another such metric.. It's a shorthand way of describing a certain kind of filter (bandpass with symmetric skirts). A shape factor of 6 is a lot different from 2, but the difference between 1.1 and 1.05 is less so, in terms of practical significance. if you really want to specify adjacent channel rejection, then that's the spec you should be working with (i.e. 3dB bandwidth of X kHz, 60 dB down at X+Y kHz) Also, watch out for stopband bounce.. I work with a variety of analog filters that have fairly steep rolloffs, a deep null at about 2.5-3x cutoff frequency, but that only have 30 dB of rejection far out. Why? Because other stages provide the far away attenuation, but I'm concerned about suppressing the spur at the clock rate from the glitch energy in the dac. The filter might have a fair amount of phase ripple in the passband, but I can compensate that in the equalization in the digital data stream going to the DAC. But, if I were to look at just the digital filter characteristics, it would look terrible. It's the overall system performance that you're concerned about. A similar strategy is used in consumer audio DACs. They take the digital stream at 44.1 kS/s, interpolate it it up to 192k, then run it to
Re: [Flexradio] Filter measurements
At 06:39 PM 2/18/2007, Tom Thompson wrote: Jim, Maybe shape factor is the wrong term to use. All I know is that I took a relative low phase noise source, a HP 8640B, and tuned the SDR so that the signal was in the bandpass with the filter set to 1000 Hz. I then retuned the SDR so that the signal was 6db down. I then retuned the SDR again so that the signal was 60 db down. If I divided the 6 db bandpass by the 60 db bandpass, the number was about 1.1. If I followed the same proceedure with the filter set to 100 Hz , the number was 2.7. What causes the difference? So, we have 1100 Hz for -60 dB bandwidth (roughly) for the 1000 Hz filter case. and 270 Hz for -60 dB bandwidth (roughly) for the 100 Hz filter case. Note that in both cases, the skirt width is about 100 Hz. The actual width will depend on the buffer size and sample rate (as well as any windowing that Frank and Bob have implemented), but, based on your observations, the sampling rate in the frequency domain is around 100Hz. If you're sampling at 48 kHz, I'd guess you're using 512 sample buffers, if 96 kHz, 1024, etc. Did you have spur reduction on or off? To get rid of the peculiarities from that, you can retune the 8640. Although, I don't know if you can tune it in small enough steps. You can lock an 8640, but it doesn't base the synthesis on the reference, as I recall. I think the accuracy is something like a few tens of ppm at best, when locked. The 8640 is pretty quiet far out (say, 20 kHz or more.), but might not be that quiet close in.. The HP catalog only shows phase noise in as far as 2kHz where it's on the order of -110 dBc/Hz.. And, looks like it's in a 40 dB/decade area (comparing the number at 20kHz and 2 kHz), so coming in to 200 Hz would be -70dBc/Hz, and to 20 Hz, to -30 dBc/Hz... Gonna be tough to measure filters with 10-20 Hz transitions with a generator like that. If you have it locked to an external 5 MHz source, it might be quieter, but I don't have the data on that. It would depend on the loop bandwidth and how they do the locking. Aside from measurement technique issues, the basic difference is due to the quantization of the bandpass...Depending on sample rate and buffer size, the filter is some integer number of bins wide..If the number of bins wide for the filter is small, then the shape factor will be not as good as if it is, say, 1000 bins wide. Imagine the filter characteristic as drawn on a piece of graph paper with the points spaced at (sample rate)/(buffer size) Hz apart, with straight lines between points. You can't get any steeper than transitioning in one sample Jim, W6RMK ___ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
