Softrock Pages. Initial Configuration.


And some notes about SDR including the "dongles" now available.
More and more are obtaining ready-built SDRs thinking that will save them time and trouble.
Be warned! Setting up a SDR can take more time and be more frustrating than the actual construction.

Transmitting needs a receiver to check you are on the correct frequency and to adjust transmit image rejection. 

Software Defined Radio says it all! Most of a SDR is within the computer.
Because of the wide variety of soundcards, computers, operating systems and the way they are setup there can be no simple "Do it like this" instructions. If you are not familiar with these items you may find you have a lot to learn.
Note many of the pages I refer to contain information for constructors as well as configuration, you may need to look carefully for what you want.

This site, http://www.wb5rvz.com/ contains the construction details. IT ALSO INCLUDES ALL THE SOFTWARE AND COMPUTER SETUP INSTRUCTIONS
I suggest you go through it thoroughly. Most constructors use these pages and get their Softrocks working.
This page is basically a summary of the techniques required.
LINUX:- It is possible to use Linux but I cannot help. My main page, link at the bottom, has some references. 

Computer.

Maybe a single core 2GHz is the minimum, this may need all other applications disabled. Lower performance ones may work but a fast one will not usually need "tuning". I suggest a desktop, these are far more versatile.
The RTL dongle will need a faster computer.

Connections.

12 volt power and USB if used. For receiving a STEREO line input to a soundcard and speakers or headphones from the output of the soundcard. A GOOD antenna, not just a piece of wire. 
Transmit:- Leave this until you are happy with receiving. In many cases a second soundcard will be required. See bottom of page for some Softrock connections.
Please note the socket marked "Line In" on a Softrock refers to where it is connected on the computer.

Soundcard.

Most will work. PCI, USB  and some modern on-board systems are quite good. 
It is not necessary to get a high performance card to begin.
Settings can be very confusing.
and

 The dongles do not use soundcards for an input. The FCD has its own USB, the RTL uses a different method.
 

USB Softrocks.

First the USB driver must be installed.

January 2013 NEW DRIVER INSTALLATION FILE.


From Fred PE0FKO:- 
There is a new driver installer for the software that can be
The installer will install the certificate and then install the driver (32 
& 64 bits) then the hardware can be plugged in.

Then check it with

Further instructions and links on this page, relevant for all USB Softrocks. 

November 2014. The Softrock and other USB devices use libusb0.dll It has been suggested that there may be problems with earlier versions of this file. If you have problems with USB3 or later versions of Windows it may be an idea to update this file https://github.com/libusb/libusb/wiki/Windows 

Software

It is a good idea to get receive working first. An easy to setup program is SDR# (SDR Sharp) this is my recommendation, see this page
Do not adjust the bandwidth, filters or any other receiving settings until you have got it working. Default settings on all software will give good results.



The dongles need software to be configured specially. SDR# is again the easiest, but read carefully about the RTL.


This page shows SDR Sharp   https://sites.google.com/site/g4zfqradio/connecting-soundcard-sdr-to-computer and gives some hints about soundcard setup problems.

This page http://sites.google.com/site/g4zfqradio/installing-and-using-hdsdr gives basic installation details for  HDSDR a Winrad derivative. This will give receive and transmit capability with all versions of Windows. 

This page http://sites.google.com/site/g4zfqradio/setuprocky shows Rocky, this older RX and TX software is increasingly giving problems with current Windows installations. Most of the instructions for using Rocky are on it's download site. To add more frequencies to Rocky's drop-down selection http://www.wb5rvz.com/sdr/RX_V8_3/Sw1Settings.htm relevant to USB as well. Or paste and copy from my list. http://homepages.wightcable.net/~g4zfq/Si570/40FreqRocky.txt 


Use one or the other of these programs until you have everything working satisfactorily.

Here is a link to a discussion opened by a beginner, just about everything is covered http://groups.yahoo.com/group/softrock40/message/49895

Links to other SDR software on my main page, link below.

Connections.

Basic connections here for a Lite http://www.wb5rvz.com/sdr/sr_lite_ii/07_extconn.htm 
Basic connections for an Ensemble, this is the VHF one but HF is the same. http://www.wb5rvz.com/sdr/ensemble_rx_ii_vhf/08_extconn.htm

Basic Use of SDR Programs

A band of frequencies is displayed on an SDR screen.
The width depends on the sample rate of the ADC used. This may be the soundcard. All will operate at 48KHz, some higher. The FCD is fixed at 96KHz, the new Pro+ up to 192KSPS. The RTL from 2MSPS down. (SPS, Samples Per Second, same figures just a more correct name.)
There are two frequencies to consider, the centre frequency (Local Oscillator) and the tuned frequency.
The centre frequency defines the band of frequencies shown. Do not set the tuned frequency near the centre, always keep an offset.
Because of the way SDR works operating near the centre can give problems. Right at the centre is a dead spot where nothing is received, some soundcards, including the FCD, show a sharp spike there. The RTL shows a big band of noise at the centre in my setup.
Some software hides these effects but does not remove them.

"IQ" Signals

A soundcard SDR is fundamentally a direct conversion system. The problem with direct conversion is that signals both side of the local oscillator (LO) are produced. As an example the Softrock SDR splits the RF signal into two signals with 180° phase difference between them.
Two mixers are used, the LO is split into two signals 90° apart, each of these is sent to a mixer, mixing with the split RF signal. The two signals that come from the mixers are known as the IQ signals, 90° apart. These signals range in frequency from almost zero Hz up to half the soundcard sample rate. Because they have a phase difference the computer can cancel out the duplicate "image" and show a display as wide as the soundcard sample rate with the LO in the middle.
If there is a fault, one of the IQ signals is missing for example, then this cancellation will not be possible and signals will be duplicated each side of the LO.

Funcube, beginners use SDR Sharp.
Or HDSDR With HDSDR you must put the DLL in its working folder, use the DLL found here:-  http://www.hdsdr.de/hardware.html
All information is here. http://www.funcubedongle.com/ Run your mouse over the black header.
If you use Chrome this page translated is good http://www.qsl.net/py4zbz/FCD.htm 
SDR-Radio will work with it. I am reluctant to guide an absolute beginner to this software but here is a start http://groups.yahoo.com/group/sdr-radio-com/message/10836

RTL Dongle
Driver installation on HDSDR's site http://hdsdr.de/RTLSDR_with_HDSDR.pdf This technique is valid for all software. Be careful! It is easy to assign the driver to the wrong device make sure "Bulk Interface" and/or the correct VID/PID is selected.  See here
With HDSDR you must put the DLL in its working folder, use the DLL found here:-  http://www.hdsdr.de/hardware.html


G4ZFQ March 2013
alan4alan at googlemail com

More of my pages related to SDR

Main reference page:- 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 use Ctrl-F on your keyboard to bring up a search box to find keywords.

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