softrock

Thu May 30 17:45:06 CDT 2013

Hey Alex.
I’m not sure what on-board sound chipsets are the best.  Generally, you get whatever that particular motherboard has, and if you don’t like it, you need to install a sound card.  The older USB sound card that people liked was the Creative EMU 0202.  I believe its replacement is not as good.

Depending on how good your soldering sills are, either the Ensemble II receiver or the Ensemble RxTx are good choices if you are comfortable with SMT.  They both rely on the Si570 chip for he LO, which allows frequency agility – a huge benefit.  These are both HF kits.  The receiver covers all of HF, while the RxTx is a small transceiver that covers one band really well, and another band OK.  The crystal-based Softrock kits are much simpler to build, but are stuck on whatever freq the crystal is for.  For 40M, the main Softrock frequency is 7.056MHz, for example.

Softrock Ensemble receiver ($67):
http://fivedash.com/index.php?main_page=product_info&cPath=1&products_id=6&zenid=fc11d0c66aca3263e3f48f1e58894fb0
Softrock Ensembe RxTx ($89):
http://fivedash.com/index.php?main_page=product_info&cPath=1&products_id=7
Softrock crystal receiver ($22):
http://fivedash.com/index.php?main_page=product_info&cPath=1&products_id=5

Fivedash (Tony Parks) used to run out of these kits all the time.  You may have to monitor the web site for in-stock opportunities.  There are also some Softrock-like kits out there as well. Lazy Dog is one company making a similar kit.  Bill Fenn has a crystal-controlled version that he purchased from Japan.

Almost any computer over 1GHz will work somewhat with simpler SDR programs, such as Rocky.  Windows XP and higher are OK as well.  Higher speed computers and/or newer versions of Windows (or Linux) will provide additional benefits, such as a wider receive spectrum – assuming that your sound card allows it as well.  Most SDR apps are 32-bit, generally so that they can run on a 32-bit OS.  There have been driver issues with 64-bit Windows as well...  For Apple devices (iPad/iPhone/iPod) there is a free iSDR app for that.

There’s a LOT of options in both hardware and software for SDR these days.

You may have also asked about slices of spectrum are displayed.  From what I’ve seen so far, each slice has been displayed on a separate line (in PowerSDR).  There is talk in the HPSDR group about splicing adjacent spectrum slices together, but I think that’s more for a spectrum analyzer project.  The new Flex radios, and some others like our own Charleston SDR, can suck in wider spectrum data, and that data can be displayed directly as a wider swath.  But, this isn’t true for sound card-based SDRs.  This is another advantage of DDC-based (Direct Digital Conversion) SDRs versus the cheaper QSD-based SDRs, which rely on sound cards (the Flex 1500, 3000, and 5000 have internal sound card like interfaces).
73, Terry, WB4JFI

From: Alex Fraser 
Sent: Saturday, May 25, 2013 2:51 PM
To: tacos at amrad.org 
Subject: Re: softrock

Yes Terry your reply was very helpful.  I wish I could clone myself as there are so many fun projects to get into.   Some like the entry level SDR softrock are fairly inexpensive and the way technology is these days a lot of projects can be done on a low budget.  Time is the limiting factor.  If you can do it in an evening I would guess it might take me a bit longer, but not so long as I can't fit it in.  So many rainy day projects and the summer is just beginning, so some will not get finished till the fall :-)  I think I'll buy something now as it looks like the kits come and go.  Recommendations? The softrock receiver looks like a good start and I can start hunting around for sound cards, which brings up that technology.  

    Often motherboards come with built in sound these days.  What are the best chip sets?  Also I lurk in the used market so the brand and model of the juicy older sound cards and/or devices would be very helpful.  If I run into a bunch of them I'll post the treasure map here first.  

    I assume that if a machine can edit HD video fairly quickly that it can do SDR processing, is this a valid assumption?  For a PC, multi core P4's with oodles of ram seem to work for that when the clock gets past 2.4 gig.   Is 64 bit SDR software around? Preferable?  I can do Linux, but when lazy use Windoze 7.  Is XP doable?

    As for application, well I saw that glsdr app on my phone and wanted a SDR remote server right away, but I must move one step at a time and I'm still doing baby steps (even crawling).

On 5/25/2013 1:34 AM, wb4jfi at knology.net wrote: 
  I have at least one each of most of them, and some of the similar QSD/QSE radios.  They are good, lower-cost entries to SDR.  The crystal controlled versions were cheaper than the tunable ones, with the Si570 oscillator used on tunable units.  Most are better as single-band units, even though they may cover multiple bands.  Most of mine are for 80/40M, but I have a few for 30M or 20M.

  If you mean the official Softrock kits from Tony Parks, they have a little SMT, but are mostly through-hole parts.  The SMT parts are the QSD/QSD switches, opamps, and bypass caps.  The SMT is generally easy to do for anyone that knows which end of the iron will burn your fingers.  You also have to wind all the coils, toroids mostly.  I can build most Softrock kits in less than an evening.  Winding the coils takes up the most time.

  You will need some decent software, especially for transmit.  Since they are QSD/QSE-based, there can be significant image problems and carrier leakage if not tuned up right.

  IMPORTANT:
  The single-biggest thing to realize with Softrocks, like all QSD/QSE radios, is that your COMPUTER SOUND CARD is the MOST important part of the lash-up.  IT determines how good or bad your experience with a Softrock will be.  If you have a poor soundcard, you will have image reject problems, lots of birdies, a BIG spike at center-frequency, limited bandwidth spectrum display, and a host of other issues.  If you have a REALLY GOOD sound card, most of those problems just don’t come to play.  24-bit is not as crucial, but can show slight improvements.

  You can spend $80 on a Softrock, but if you use a $10 sound card, there will be more problems.  If you spend $80 or more for a decent sound card, you will be rewarded.  A couple-hundred firewire-based sound card works real good, even at 192kHz.  Finding a decent/good USB sound card is a big challenge.  There used to be a good USB sound card, but it has been discontinued.  Most are pretty poor.  For desktops, get a decent internal sound card, or firewire.  For laptops, it’s firewire.  Or, an internal sound card if stereo inputs are found.

  You will need STEREO inputs as well as outputs, for I and Q.  Most laptop sound cards are mono mic in, and don’t really work.  Well, they do, but you cannot get rid of the image of signals.

  What are you planning to do with it?  For example, only messing with HF PSK31 does not require as wide a receive bandwidth as a general-coverage unit.  Sometimes only one frequency is required, such as CW QRP near 7056K, and a crystal controlled unit would suffice.  HF? VHF/UHF?

  The RTL dongles everyone is buying are fun, but they cannot approach even a Softrock for a decent SDR on HF.  With only eight bits A/D the dynamic range is rather limited.  I measured only about 60dB at 100MHz on one of the ones that I have.  For HF, you should have nearly 130dB, according to Mitola.  Of course, it’s all relative.  Ya gets what ya pays for.

  There are SDR programs for Softrocks for Windows, Linux, and Macs.  I’m most familiar with some Windows and Linux versions.  Rocky is probably the all-time simplest (www.dxatlas.com I think).

  Does that help at all?
  73, Terry, WB4JFI

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://amrad.org/pipermail/tacos/attachments/20130530/facfbc77/attachment-0001.html>