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A new project - TS-940 with SDR panadapter

Discussion in 'Home Brew' started by SR385, Feb 12, 2009.

  1. SR385

    SR385 Active Member

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    Well, it's new to me at least.



    I'm going to do this...

    Welcome to Amateur Radio station WU2X

    A kit called a softrock that connects to the 8.83 IF output of the TS-940 and feeds data via a soundcard into the PowerSDR software.

    PowerSDR becomes a software defined panadapter and also does the demodulation and filtering of received signals.

    I'll slave the PowerSDR to Ham Radio Deluxe and that way, when I click on a signal on the panadapter it will tune the rig along with it for TX. The same happens when you spin the VFO on the rig, the panadapter RX follows you as you go.

    Basically you get all the features of receive that a Flex radio has (very close in spec overall) for a heck of a lot less money than buying the full monty.

    To see what I'm really talking about, though using different hardware and software, this video shows the deal in a nutshell.

    YouTube - RFSPACE SDR-IQ with Kenwood TS-830S

    I'll update as my project moves along...will take me a while to get it all together.
     

  2. Moleculo

    Moleculo Administrator
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  3. SR385

    SR385 Active Member

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    Yeah but I found out...not as straightforward as I'd thought.

    If I go that route it's using third-harmonic sampling with the crystal available.

    I'm looking into a substituted value for the crystal.

    I may just suck it up and skip this part and buy an LP-PAN from Telepost as that would be a plug and play operation. It's designed specific for this use.
     
  4. Lazybones1222

    Lazybones1222 W9WDX Amateur Radio Club Member

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    Very nice. I noticed the TS-480. Have you made an interface for that radio to use with your screen or would you use a store bought one?
     
  5. SR385

    SR385 Active Member

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    Ah that's not my video, just an example of what I'm going to do here.

    Got a TS-680 a TS-2000 and now the TS-940 here.

    I was originally going to hack either the 680 or 2000 but they don't have an easy spot to tap in front of the roofing filters. That means if I did that I'd only be able to see about 15kHz on the spectrum vs the 192kHz I should see with the 940.
     
  6. HiDef

    HiDef Active Member

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    I would like to try one of these in the near future but I'm waiting so I can copy someone else's homework:laugh:

    Just curious. Would there be any advantage to marry the SDR to the first I.F. at 45.05 mhz instead of the 8.83 mhz second I.F. ? I would think the second I.F. would be more narrow due to the transformers between stages.

    Best of luck with the project.
     
  7. SR385

    SR385 Active Member

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    Yeah the whole point of tapping at the IF before any filtering is to have a wider spectrum view feeding into the SDR for processing.

    I could tap the 10.x Mhz on the TS-2000 as an example and it would have a bunch of filtering in ahead of it or the 455Hz IF on the 680, but you only get 15kHz vs 192kHz of spectrum to 'play' with in the SDR.

    The first priority for me is a wide view of the band to click around for signals. Second is the filtering ability.

    As you are listening, you can use the rig with it's filtering as the RX and/or the SDR audio output so if the SDR for some reason isn't as good as the rig's selectivity, you can just toggle what you are listening to once you tune in.

    ===========================

    I read what you said wrong, yeah it might be a better option, but you would need a 180Mhz crystal to use that IF and the IF tap on the 940 is already there from the factory at 8.83 buffered as well.
     
  8. SR385

    SR385 Active Member

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    O.k. so a status update.

    Hardware is as follows

    Kenwood TS-940
    LP-PAN for 8.83 MHz IF from Telepost Inc. Home Page
    Edirol FA-66 firewire soundcard
    PIEXX RS232 controller for the TS-940
    2 balanced audio lines from stereo mini to XLR
    Heil foot switch...using secondary line to 'mute' on the LP-PAN for TX mute

    It goes like this

    IF output RCA plug on the TS-940 into a BNC plug for IF input on the LP-PAN

    Two balanced audio cables from the I and Q audio outputs of the LP-PAN into the Edirol soundcard

    Mute connection (RCA) to the unused secondary cable on a Heil foot switch to the LP-PAN. This mutes the IF while transmitting so I don't get feedback on my own audio signal. It can be skipped but you'll find it very annoying to hear yourself with the delay/latency in processing...it will make you tongue tied to listen to it while talking.

    Software varies in combinations.

    Ham Radio Deluxe for CAT control of the TS-940, controls the frequency of the VFO via the computer for this use.

    PowerSDR-IF Stage, the IF-Stage variant is significant here, it's specifically modified to track the VFO of the rig with the VFO of PowerSDR and keep a constant IF offset alignment.

    Alternately to PowerSDR is Winrad. Winrad won't tune the rig though, you tune the rig on your own and Winrad 'chases' the rig.

    PowerSDR-IQ is yet another...it is a more advanced version adapted than the IF Stage version with better processing and far more image rejection, however....it isn't done yet for this particular use so you have to tune it up for the frequency you are on and that's it...once you tune the VFO of the rig away from that 'center' frequency, you have to line it all up again. It is due to be modified I believe so that it will have full function.

    What does all of this do for you?

    Well my transmit is plain old TS-940, which is to say about 2.8kHz with audio processing and about 2.6'sh with a mic right into the rig. It's great audio, but not Hi-Fi. A good compromise though for most use on SSB.

    My receive...now that is what this is all about. The TS-940 has a fixed filter. You can go narrower using the slope tune function, but you can't go wider at all. So if you are listening to nice wide band signals on a quiet night, you will never get the full quality from the TS-940.

    With my setup, I have infinite filter width and shift selections. I can go to 10kHz wide or wider and at whatever passband I like. I can go down to 50Hz wide if I want to. This allows me to see the signals on the screen and see where the interference is coming from and simply click and drag the edge of the filter until it disappears. I only have to apply the bare minimum filtering to get around the interference.

    Now the 'panadapter' is where you see the spectrum. As I mentioned it lets you see the signal you are listening to and also any adjacent transmissions. The width of spectrum you can see is limited by the sampling rate of your sound card. My sound card gets me right around 180kHz. 192kHz really but it drops off on the ends. What this means is, if I'm centered on 3.800Mhz I can see up to 3.890 and down to 3.710.

    Any transmission within the pass band of the panadapter can just be clicked on and listened to. I can leave the primary RX at 3.8 and have the rig auto tuned to TX there and open a second receiver to monitor anything else within the 180khz range with 3.8 being the center of it.

    Winrad doesn't have the second receiver option unless you listen to the primary frequency for TX through the rig speaker and then use Winrad to tune into the surrounding stations. Also, with my setup....at least from what I can find, Winrad doesn't read the frequency of the rig or tune the rig when I move around inside Winrad. With the PowerSDR IF Stage, when I tune the rig, the software follows in frequency display. When I click in the software, it actually tunes the rig all lined up for TX when I hit the switch.

    The software also allows me to record at a click. Now...you don't just record what you are tuned into, you record the whole spectrum that you can see at that time. So when I record, I get the entire spectrum of 180Hz at once. When I play that file back, I can actually tune it as though I'm listening to it live.

    So one great example...if you are being jammed, those guys are generally just up the band talking it up and planning what they are doing and using their call signs. Simply hit record, don't say anything and when you get a chance, play it back later and tune around until you find them...callsigns and all.

    You also have various display types you can toggle. You can see audio spectrum, a panadapter frequency spectrum, a waterfall and a few others depending on software. This is very useful in analyzing signals to let people know if their rig is not performing properly or to help people figure out any issues they may be having with their signal.

    In addition to all that, you have incredible DSP noise reduction, noise blanker, auto notch filters...basically anything you want to do with the signal can be done and is either already done or being worked on.

    A download of new software and you have a totally new radio...or in this case just a receiver.

    This is all quite beta. You'll have a pretty frustrating learning curve to figure out lining up the IF offsets, audio sampling rates and buffer sizes and all the features available once you get the initial configuration done. Don't do this if you aren't into tinkering around with software and computer settings....just don't do it. If you are up for the adventure though...it is pretty amazing stuff.

    The software is all free by the way...all of it.

    This should also all work in linux with linrad and likely SDR-Shell, but I haven't gotten around to that just yet...just made up all my cables and got it plumbed on Saturday.


    LP-PAN LP-PAN.html
    PowerSDR IF Stage Welcome to Amateur Radio station WU2X
    PowerSDR-IQ powersdr-iq - Google Code
    Winrad Winrad.org
    Linrad Linrad home page
    Edirol FA-66 EDIROL FA-66 24Bit/192kHz FireWire Audio Capture :: Overview
    PIEXX interface board TS-940 Interface Board - $89.00 : Piexx Company, Computers & Electronics
     
  9. SR385

    SR385 Active Member

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    This configuration will work with TS-450 (Not 100% on this one),TS-830, TS-850, TS-870, TS-940 and TS-950

    Any of the Kenwoods with the 8.83 IF tap out for use with the SM series station monitors will work.

    There is also an LP-PAN for the Elecraft K3 and actually the software is more integrated with the K3 than with my setup, it works very nicely and here is a youtube showing a full run through with the K3 integration which is closer to what I have than my first video posting.

    YouTube - PowerSDR/IF Stage Elecraft K3 Part II
     
    #9 SR385, Mar 3, 2009
    Last edited: Mar 6, 2009
  10. SR385

    SR385 Active Member

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    So gradually I'm ironing out the details as I go along.

    I now have about $15k in test equipment on loan, including a GPS disciplined double oven time source and a bunch of HP gear to fiddle around with aligning the software and my rig to be in sync for s-meter level and frequency. It's all very ridiculous but it was a lot of fun getting the run down on how to use all the gear hands-on. My TS-940 is far more accurate than it ever needed to be now heh.

    Some software tips. When using Ham Radio Deluxe or another serial comm application with SDR software running, if you set CPU priority on the SDR to make it run more smoothly, be sure you set the priority of the serial com rig control app to the same level or you will possibly have bus conflicts and get garbage data going to the rig. The 940 had been hopping around in mode and frequency a bit randomly before I came across this tip. Now it's all good again.

    There will be a release coming up for the PowerSDR-IQ patch branch of PowerSDR that will make it work properly for IF stage use. This will be great as it is a generation newer code base than the PowerSDR-IFStage version that is out there now. Many more of the functions in it work properly and it has other advantages as well.

    I also understand that LP-Bridge will be released to work with Kenwood rig control. This will eliminate having to run HRD just for rig control comms. It's lighter weight and a bit more straightforward to set up.

    Watching the panadapter is extremely addicting. You really have to sit down and use one for a couple hours to begin to see what you can get from it. The whistles that slide past you, you can now see on the display as they sweep the entire band. Typical of someone using a VNA to sweep their antenna system. People with flat-topped overdriven signals are clear as day once you get used to tweaking the waterfall for the proper gain and contrast. Spectrum analysis is child's play for signals you hear and also for looking at your own signal.

    This is a lot of fun and I think I've broken my brain forever as far as using a radio 'blind' again.
     
  11. SR385

    SR385 Active Member

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    [​IMG]

    A new toy has arrived, a QS1R software defined receiver. The screenshot is the SDRMAXIII softwware that runs with it, all compiled from source and running natively on an Ubuntu 8.10 system. This is a Cadillac SDR receiver...it's amazing.
     
  12. HiDef

    HiDef Active Member

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    Cool. Thanks for sharing!
     
  13. SR385

    SR385 Active Member

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    No problem, it's an obsession now, this is all too fun.
     
  14. wb0gaz

    wb0gaz New Member

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    I found this thread by searching for TS940S and Panadapter - lo and behold here it is!

    After completing the 160 meter contest this weekend, I decided I need a FFT panadapter for my TS-940S, however, my desire need is to watch frequencies very close to the IF (+/- 2.5 kHz would be ideal - I'm interested mainly in "are there signals very close to mine?)", rather than seeing a wide spectrum which seems to be the common use case for SDR software.)

    I'm using a generic RTL-SDR, a homebrew upconverter (to get 8.83 MHz into the tuning range of the RTL-SDR), and HDSDR software. From a hardware perspective, this all works; it's the software I'm focusing on.

    The problem is that HDSDR's minimum bandwidth/sample rate is 225001 Hz, which means that signals within a 5 kHz passband are too close together to resolve.

    Do you have any recommendations for SDR software that supports the RTL-SDR and also allows a narrow bandwidth such as this?

    Thanks very much!

    Dave
    wb0gaz@yahoo.com
     

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