More Softrock’ing this time with si570 Sythesizer

A Skype call from out of the blue brought a Softrock A1 Lite+USB Xtall v9.0 in the post. I missed out on this model, I stopped following the development after building my Softrock TX/RX v6.1.

When Alun the owner mentioned USB Lite I thought only of the original Softrock Lite which got its power from the USB port and put its audio into the USB too. I knew of the si570 developments of add on si570 Synthesizers, I have a board which could be used on my v6.1, but not of an integrated Lite kit. Therefore a couple of Skype calls were a bit at cross purposes until it dawned on me that as the computer was asking for USB drivers there must be an si570 involved. Alun downloaded the drivers and got only some very patchy results. Having owned the SDR for a time, it was a supplied fully built unit, and struggled before without success it came my way.

On arrival in the post it rattled rather, that was just some board fixing hardware that had come adrift but it did mean I needed to open the box and re-fit the bolt. As I lifted the board the antenna lead snapped off, an odd one that, the small diameter coax is secured Softrock style by a 2 turn loop of copper wire. The PVC outer, braid, centre core and its polythene insulation all snapped clean after the loop. I can only suspect that the loop was too tight and too much heat was used when soldering thus circumcising the coax. Now that could be a good cause of intermittent signals.
First job then was to re-make the connection.

Next I connected up the board and set up the si570, it should store its last setting but it was showing its internal oscillator frequency. I set it to 28.2 MHz, for a 40m centre frequency of 7.05MHz x 4. Then I started Rocky, it worked nicely, CW and SSB signals were copied and BPSK31 was decoded FB. This is a nice RX and would be easier to modify to 500kHz, hmm, pity it has to go back to its home.

This blog entry will now take the form of a simple quick start guide to using the A1 Lite+USB Xtall v9.0 with Rocky 3.6.

First download and install Rocky 3.6 from HERE.

Next download and install the DG8SAQ Synthesizer Driver and Firmware from HERE.

Also download and install the USB Stand Alone Synth from HERE.
You can operate the Softrock without this but it is such a useful addition I wouldn’t want to be without it.

TIP If at any time the Softrock does not perform as expected remove the USB plug and re insert it, like all things the si570 synth can have a glitch.

On your desktop you will now have these short cuts.

Plug in the Softrock, 9 to 12 Volts Power, to avoid hum loops it is always best to run SDR’s on a battery supply. Stereo Jack to Line in on the Computer, USB and Antenna. On first use Windows will find a new USB device, allow Windows to automatically install the driver.

On all subsequent uses of the Softrock there will be no setting up do do at all and no messages from Windows.

Double click on the USB_Synth Icon the GUI will open. If all is well the Synthesizer online will show Green and the last frequency entered will be displayed, in this case 28.2MHz.

Close USB_Synth and double click on the Rocky Icon, select FileStart Radio, then – ViewSettings.

Right Click and select View image to see the complete picture.

Set your Sound Card in use as I/Q Input Device and Audio Output Device, mine are different sound cards for convenience, they can be the same card for in and out. Leave the Sampling Rate at 48kHz for most standard sound cards, there is no frequency coverage advantage with the si570 by using a 96khz card. Channels Left/Right Q/I is normally correct unless you find the band to be reversed.

Click on ViewSettingsDSP, select Use Si570-USB – set Address to 55, Divider to 4. The Local oscillator box shows the centre frequency of the Rocky tuning Scale. Rocky automatically adjusts the scale to show the correct frequency.
To move the frequency coverage around the band alter the 7050000Hz to 7060000Hz…7180000Hz etc. Do not forget to hit OK to close the box and enable the new setting.

For use on 80m and other bands plug in the appropriate BPF and set an appropriate centre frequency.

Right Click and select View image to see the complete picture.

I think Rocky is the best SDR software for the Softrocks. A very nice facility is the Automatic I/Q Balance,select ToolsAutomatic I/Q Balance and just leave it alone to just do its job continuously. Another the very useful thing Rocky provides is the direct de-coding of BPSK31 just select Mode BPSK31 and point the cursor at the centre of the signal.

Right Click and select View image to see the complete picture.
Next time you want to use the SoftrockA1 Lite+USB Xtal with Rocky all you need to do is double click on the Rocky Short Cut Icon.

Do not forget the very useful Waterfall View.

Right Click and select View image to see the complete picture.

Just use USB synth as a diagnostic tool or if you wish you can change the Local Oscillator frequency using the frequency setting window. However if the frequency is changed by this means the Rocky scale will be off as it will not follow the frequency variation and the calibration set in Rocky will not apply.

I wanted to provide a simple way of re-setting the calibration without any further need for a reference, I therefore started to play with ToolsSi570 Calibration , going through the process several times. Well you can definitely confuse Rocky this way, the calibration no longer made any difference and control of the Si570 frequency didn’t work, often after an attempted frequency shift the oscillator stopped completely.
I tried re-starting Rocky, the computer, altering and deleting the calibration figure and even deleting the Rocky Config file. Finally the only cure was to un-install Rocky and delete everything left in its folder and re-install. This worked fine, so if ever you get problems this will be the best course. This should be the only time that re-calibration should be necessary so the following screen shot shows for the record the dial Frequency to set on Rocky and the True Frequency to enter into the Si570 Calibration window should it ever be reinstalled. This figure of course applies only to the Si570 in this particular Softrock A1 Lite+USB Xtall v9.0.

Right Click and select View image to see the complete picture.

This has persuaded me to give it a little more intensive testing before returning it to its home to see if I can create more glitches. I want it to perform without problems upon its return.

Softrock Lite II for 500kHz and 136kHz

Your intrepid, no expenses spared blogger wanted to try an SDR on 500kHz. Being a big spender and having some PayPal bonus vouchers to redeem I splashed out and purchased a Softrock Lite II 80m Kit, it cost me £4 that !!

Jim Moritz published the details for converting the old Sotfrock Lite to 500kHz and 1softrock-lf36kHz, there is not a lot of difference so I reckon that it should be OK.


The main difference is the lack of divide by 8 so a 2MHz Xtal will be needed for 500kHz, as for 136kHz we must experiment.

First step for me was to build and test on 80m, my other SDR is 40m TX/RX so 80m would be a nice band to keep available. Hmm, I suppose I could spend another £4.


I must say it performs very nicely on 80m although FULL band coverage still needs one more Xtal than the 4 I have.


Well I spent the other PayPal voucher on a 9m glass fibre pole so I followed my original idea of making the Softrock Lite II 80m easily changeable to 500k and 136k.

First of course we need changeable, plug in Xtals, no problem. The Oscillator/Buffer has a bias change for the lower frequencies, 2 resistors need to be removed and another added. I mounted those on spigots for ease of removal. The other changes in this department are added capacitance, this can be added to the rear of the board.


The front end is the other change, we must built an LPF which will be too large for the board so this will be separate, this feeds the input transformer which must replace the 80m component.
To achieve this easily I have provided tabs to mount L1 and T1 for ease of swapping.


It won’t be a luxury band switch job but at least it’s not butchery. Now I need to find a source of 75 material toroid cores.


9kHz Radio – The Dreamers Band

Just a short while ago the subject of operation below 9kHz was mentioned, the chief LF grump, sceptic, policeman and expert said “you are all dreamers and won’t get over your garden fence at that frequency”.

The band became the “Dreamers Band”, DK7FC with some youth on his side got moving, yesterday he carried out a second test, using a kite flown 100m vertical wire his signal was identified to all but the greatest sceptics at a distance of 830km.

I can only sit back in awe of the expertise and energy involved and marvel at the results and the pictures on Stefan’s Site. Congratulations to him and all involved.

BTW regarding the snow picture, in the UK such conditions would force most of the population to abscond from work and public transport to be cancelled, someone could slip you know.

New RSGB Band Plan 2010

Like all things the Internet brings good and bad points. Good in that information is rapidly available. Bad in that the old information stays ‘for ever’.

Search for RSGB Band Plan and you get this OLD ONE with a note that 40m will be re-planned before March 2009bandplan-old


Is this because you are a fool, maybe you should have searched for RSGB Band Plan 2010 the exact title on the top of the plan. Not so, the nearest you get is a front page picture of the February 2010 RadCom Magazine in which the new plan was printed.

Second from top in the search is HF DXer here there is a Feb 2010 reference but the multi page Adobe plan is the 2007 vintage model.

The seventh item that a Google Search brings up contains February 2006 in the title.

Maybe this blog will change that situation.

No wonder there is yet more ill feeling among Hams, the new IARU Plan was agreed in 2008. Published by the RSGB in February 2010 RadCom and still hardly anyone has heard about the changes to the 40m plan.
Once again communication is what the communicators do really badly. I am not going to copy the RSGB plan and publish it here, that is for the RSGB to do.

Here is a tabulation of the Major changes on 40m.

7.000-7.040 is now Telegraphy

7.040-7.050 500Hz Narrow Band Modes

7.050-7.060 2.7khHz Digimodes

7.060-7.200 2.7kHz All Modes Voice

Some German stations have decided to cause QRM to PSK31 users with high power CW transmissions in order to let them know the changes. Many will be stubborn I am sure. Me, I shall be where the Band Plan says for the mode I am using. At least then I can complain about the QRM caused by some fools who still insist on using phone around 7.030.

BTW, the RSGB almost got it right this year. The annual Band Plan was always a pull out supplement in RadCom, I have them in my drawer in my shack for reference. Then one year they gave the job of producing it to their staff member, the spotty school leaver lad who has no interest in radio. The Band Plan was bound within the Magazine I disassembled mine and re built both, the mag now had parts of articles missing and the Band plan was a mess. I wrote to the RSGB pointing this out. I seem to remember that despite no acknowledgement of my mail the plan was pull out again for a time.
Then it crept back to being an inseparable part of the February issue. This year you can pull it out but the back page contains the first page of an article so you ruin your archive able magazine.
There are innumerable adverts that could have gone on that back page, hey RSGB maybe an advert on a long lasting pull out could even carry a premium. Another little thing that spotty lad knows nothing about is that the Band plan used to not have sequential magazine page numbers on it. Why is it now far beyond the mind of man (spotty school leaver) to number the 6 page plan i ii iii iv v vi, nah! that was the ancient Romans that did that and they knew nothing about radio.

EDIT 15March I have noted that the new plan is now on the RSGB site if you manage the right search. Is that not the nicest front page of irrelevant information you have ever seen?
In answer to queries, the new plan was effective from 1st January 2010 according the February RadCom. The above web version says 29th March regarding 40m, oh dear! are you confused yet.

GW6ITJ has gone to the trouble of producing a nice Graphical Plan which can be viewed, downloaded or printed, (2 pages).

I think this was printed in Practical Wireless. Of course there are those who say that this is not the ‘official plan’ due to the personalisation. Those who do not want to comply only need the slightest excuse.

FCC give thanks

The FCC has contacted the author to express their thanks for the technical information provided on this blog.

Agent 36543210 said:-

Thank you for pointing out that ROS Digital is merely a 2.4kHz wide MFSK mode and that even if Spread Spectrum Techniques are used, any coding algorithm involved cannot be secret and used as a cipher for nefarious purposes as the software freely provided contains the algorithm for both coding and decoding the signal.

We now understand that if we downloaded the software we would automatically have the means to both determine the nature of the mode and decode and monitor all transmission made using the software.

Given this revelation we hereby declare the mode legal in the whole known inhabited earth.

Thank you

Your indebted servants FCC (Fred Karno’s Circus)

With just a little poetic licence regarding the acronym letters used.

Please note:-
This post is a joke. Just in case you haven’t realised by now. At least it is an attempt at humour, in no way could it compare in hilarity to any real life story.

ROS arguments go on and on

I will not join in in this war of posts to groups. I will just sit and smile, as usual.

Why are hams so capable of causing constant aggro and ill feeling, with continual bitching posts to every radio group on earth, and in their blogs, about ROS but not capable of grasping the metal and making a decision for them selves.

A quote:-
“The FCC expects you too determine if you are legal are not…Thats why we have a license process.”


Today on 14MHz 1 baud I was called by a series of stations, some quite low signal strength. Sometimes 2 stations called at once, ROS sync’d on the strongest signal the data stayed intact, due to the slight frequency difference I think, even when calls overlapped for a time. The weaker station waited and called after the first caller had completed, all in all the mode did well and the operators were good too.

There were tuners, whistlers and aaaaaloooas present on the frequency and also some Olivia signals which I have not heard for some time. ROS was not troubled by any of them.

It is time that people calmed down and just let time and the mode just take its course. I am sure some of the controversy has been caused by cunning tricks by the anti brigade.
Not since WSPR jumped on top of the 10MHz QRPp QRSS frequency slot has there been such high tension among the gentlemen who usually agree and live in peace.

Careful boys you may be being used. We don’t suddenly need to be regulated by anyone just because there is a new mode and a few folk wanting to try it.