Calibrating the Softrock Si570 USB Controller

Including HDSDR installation and operating procedure.
No manual but this should give you a start.

This procedure only needs to be done once. When the controller is calibrated correctly NO SOFTWARE CALIBRATION IS NECESSARY. Just leave this at the default settings. If you HAVE tried software adjustments then you must delete the configuration file to bring it back to default. This often needs more than simply uninstalling the software.

The Si570 local oscillator frequency is set by an AVR ATTiny85 microcontroller. The original firmware for the AVR was written by DG8SAQ but Fred, PE0FKO modified and improved it. 
This firmware is in all Softrocks produced from 2009 so the PE0FKO configuration utility MUST be used.

Initial calibration. The internal crystal of Si570s may vary +/-2000ppm. With NO calibration the frequency is likely to be a long way out. When the Si570 is made a calibration figure is stored in each. This is not particularly accurate, but is used in the initial calibration. When this technique is used the frequency may be 100Hz in error at 10MHz.

April 2012 INSTALL THIS. CFGSR Version 2.5  which you download from http://home.ict.nl/~fredkrom/pe0fko/CFGSR/  with automatic installer and new guide on that web page. (Click on "msi" ....download the correct msi file...) Note Fred details some other ways of calibrating. 
My screenshots show the earlier version but the tabs shown are almost identical.

Here is the Calibration tab similar to the one  on Fred's page.
To apply the approximate factory calibration just click the top Calibrate (A) button.
This may be done with the stand-alone CFGSR or within Winrad as described below.

To set the calibration to within 1Hz a reference signal needs to be accurately tuned.
This is easily done using Winrad. I suggest this version, HDSDR http://www.hdsdr.de/ Read the pages there and my notes lower on this page. 
Winrad and its derivatives need ExtIO_Si570.DLL to be placed in the program folder. There is a shortcut to it in the CFGSR Start Menu folder.  COPY it to the Program folder. (Drag with RIGHT mouse button) Or navigate to the program file, eg C:\Program Files\CFGSR\ExtIO_Si570

Winrad has a fairly basic interface, when first started it will fill the screen, some versions can be made to start in a window. With HDSDR go to "Options" as below. Then it will restart in a window so it appears a little more familiar.
In the set up you must select the Input Source as 'SoftRock V9.0 Si570'.
Make sure that the IQ Swap is set correctly. It normally needs to be ticked but ensure that SSB signals are on the correct sideband and that tuning is correct, that higher frequencies ARE actually to the right.
Note if you have not set "Options - Channel Skew Calibration" (Image rejection) you will see images on strong signals. Do not be confused.

The picture below shows the Phase display that is present in AM mode. This is used to tune Winrad precisely to a carrier.


This page is based on Bob, G8VOI's advice often  posted in the "Softrock40" Yahoo group. Eg.
Bob helped Fred when testing the firmware, he knows how to do it!

"I always find doing that within Winrad is the simplest method. If you use
something like 10MHz WWV or one of the other time standards, select AM mode and
fine tune until the 'phase' display slows down or stops rotating. If you then
press 'H' to call up the configuration screens and go to the 'Calibration' tab,
you can type in the frequency in the 'Real' box, i.e. 10000000 and press 'Save' (Calibrate)
and 'Read'. That should accurately calibrate the Si570 frequency."


In Europe the RWM signals on 4996, 9996, and 14996KHz  are often heard. It uses a variety of modulation types, wait until the plain carrier appears. Eight minutes of carrier starting at 00 and 30 minutes past an hour.  There is no hurry! The Softrock needs to be left for as long as possible so the frequency has stabilised.  
Click on the picture below to see full-size Winrad when tuned to RWM, but not calibrated. Opens in new window

Tuning Winrad. Place the mouse cursor on a digit. The mousewheel or left/right clicks will set it. Set LO to, say, 10KHz above the required frequency. Look on the waterfall for the signal, click on it. It may be easier to find using SSB or CW. Then switch to AM and tune slowly until the Phase display stops or moves the slowest.

Jon, EA2SN points out a trick to ease the fine tuning of the AM signal. Use ECSS mode and let the system autotune until the phase "circle" changes from blue to green. Then push H to calibrate following the normal procedure.



Below, the Calibrate tab, obtained by pressing "H" on the keyboard, or, click the "ExtIO" button. 
In the "Real" box enter the exact frequency of the calibration station in Hz. Note the figure in the "Diff" box, it shows what tuning error you have, this will confirm you have entered the correct value.  Click on the lower "Calibrate" (B) button and you are finished. Winrad should now show the exact frequency with the Phase display almost stationary.
This setting is all that is ever needed. All software will show the correct frequency provided the default settings are not altered.

If you make a mistake then click the top "Calibrate" (A) button, this resets the calibration to factory default, start the procedure again.

Note that the Startup and Crystal frequency is unique to my Si570.

It is unlikely that your Si570 will be absolutely stable. With temperature changes it may drift +/- 10Hz at higher HF frequencies but for most uses it will be close enough. 

More About HDSDR
Look at http://www.hdsdr.de/faq.html Read the mouseovers. Also keyboard shortcuts, see an HTM file in the program folder. The keys affecting tuning can be particularly useful.
This Winrad window can be resized by dragging. 
Right click-drag on the frequency scales alters the spectrum/waterfall ratio, as far as selecting one or the other.  
CW Offset:- Hold the keyboard control key and left hand mouse button to drag the centre line of the CW filter.
When in TX mode IQ swap and image rejection for TX is enabled and the Volume/AGC sliders change to mic gain and power output.
April 2012 PE0FKO has produced a DLL, with CFGSR V2.5, to go with the latest version of HDSDR, 2.13. ALL THIS DOES IS PUT A SOFTROCK TO TX, so far no CW keying.
Two soundcards required, no ASIO for TX. Spacebar works PTT 
to TX.

In "Options" you will find that PTT may use a COM port OR CAT via a COM port. 3rd party software may be connected with VAC. WSPR, for example can be used with CAT (TS2000) to set the Softrock to TX. 
So far only the "Return" key may be used for keying CW. More options promised later.
 

Probably more hidden... Let me know.

Other SDRs and devices use the DG8SAQ firmware. To the best of my knowledge this does not have this frequency calibration facility. Thought should be given to change the AVR for one with Fred's firmware. Cecil sells pre-programmed ones here  http://thepartsplace.k5nwa.com/ 

Just posted! http://groups.yahoo.com/group/softrock40/message/52372 "Re: FA-SDR TRX - does it work? Hi, Just received the ATtiny last chip with 15.14 release from Fred, and it works now well inside the FA-SRD without any click on frequency step. ( yes, ABPF has to be disabled in CFGSR screen to get the PTT line working ) - so I recommend to FA-SDR users to change the original chip provded by funkamateur, by the last release from PE0FKO. Pascal F6EHP" In fact the FA-SDR will work properly BUT only with PSDR. A special DLL is used with this SDR. Using Fred's AVR will enable the FA-SDR to be tuned correctly whatever software is used. 

G4ZFQ March 2011
alan4alan at googlemail com
More of my pages related to SDR
Setting up CFGSR for different versions of the Softrock http://sites.google.com/site/g4zfqradio/extio-or-cfgsr-some-notes

All aspects of the Softrock SDR a big page with lots of links but you should find answers to most questions. http://homepages.wightcable.net/~g4zfq/Si570.htm

 1 The Si570        
2 Getting and Making Softrocks What computer?          
3 Building a Softrock. Or look at http://www.wb5rvz.com/sdr/        
4 For Information Surrounding the Softrock  VHF converter, MOBO, PAs, Panadapter for use with conventional rigs etc.    
5 Soundcards Setting up, USB, problems.      
6 PIC/PICAXE control of the  Si570, Tony's first method. switched control without a computer. Reprogramming the PIC (and PICAXE)          
7 Parallel Port Control of the SI570.        
8 USB Control of the SI570  Information, driver installation. BPF control.       
9 Serial (COM) Control of the Si570.         
10 Some Stand-alone Controller Kits Control the Si570 independently. Links to other SDR kits.       


http://sites.google.com/site/g4zfqradio/soundcard_sdr_software Notes and links for all soundcard SDR software I know. 
Including Modes not yet Supported by these SDR Programs.  Audio Files to Test Software Without a SDR And a few links to some of the many SDRs on the web. Check them out without owning one.