Soft Rock FAQ
Version 0.2
January 22, 2009
Table of Contents:
1 Introduction to SDR and the
Soft Rock family of kits
1.1 How
the Soft Rocks Work (in a nutshell)
1.2 What
do you need to get started?
1.4 Where
can I get more Information?
2.1 Soft
Rock Kits available from Tony Parks
5.4 Who
do I contact if there is something that needs to be changed or added?
(Looking for a section maintainer and additional content)
The Soft Rock family of receivers works as follows. RF from the antenna is sent though a band pass filter and then mixed with a local oscillator to shift the frequency into the audio spectrum. Using two local oscillator signals that are 90 degrees out of phase you can obtain the “I” and “Q” signals for the RF signals that made it though the band pass filter. These signals are basically stereo audio that get sent to your computer’s sound card for conversion to digital so it can be processed by software. The software then can decode the desired signals digitally by looking at the audio data.
The kits that allow TX operation provide a means of reversing the process and taking I and Q signals generated by the software as audio and generating an RF output that is again frequency shifted back to the desired frequency using the two local oscillator signals that are 90 degrees out of phase, a mixer and an appropriate band pass filter. Yea, it’s a bit more complex than that, but this is basically what is happening with all these kits.
The key to the success of the Soft Rock is the I and Q signals interface in the audio spectrum. This means that relatively cheap hardware can be used to perform the analog to digital conversion needed to deal with signals using software. It also means that the performance of the receiver is largely driven by how good the audio hardware is and how much processing power is available in the computer that runs the software.
(RLD, 2009/01/21)
Getting started with the SoftRock family of kits is pretty easy, but you do need to have a number of things beyond the kit to make this all work. Here is a basic list, hopefully you have most of what you need already.
See the available kits section of this FAQ for ordering information but I suggest you start slow and go with the cheapest kit Tony produces. This is currently the SR Lite II which costs only $10 ($11 DX).
Soft Rock kits are ones you have to solder together and have surface mount devices so you will need some tools for this type of work. The Builder’s notes cover the list of what you will need, so make sure you have everything they recommend. Soldering surface mount stuff isn’t that hard as long as you have the basic tools you need and take your time but it is very frustrating if you don’t have the basic tools required. (Trust me on this one, I found out the hard way.)
This can be just about anything that puts out 6 to 14 volts at about 200 mA for the RX only kits. This means that a 9V battery will work if that’s all you have. Lots of folks use 13.8 V (12V) because it is common in a ham shack.
This is discussed in further detail below, but just about any reasonably modern computer with a sound card will work here. If you have a stereo line input into your sound card and an 800Mhz or better CPU you should be able to at least hear something with your SoftRock kit and learn a lot about SDR in the process.
There are a number of packages you can try, but START with Rocky.
(RLD, 2009/01/22)
Tony is the one who pretty much holds this whole Soft Rock idea together. Tony Parks (KB9YIG) and Bill Tracey (KD5TFD) designed the original SoftRock-40 kit a long time ago. Tony with some assistance from others has kept the Soft Rock set of kits up to date and available for order. Over the last few years he has added many features to the available kits, including adding the Si570 programmable oscillator and the RxTx series that added transmit capacity to the original receive only kits. He does all this pretty much for free as the prices being charged for the kits are basically just covering his costs. Thanks Tony!
(RLD, 2009/01/21)
The Soft Rock kits and associated projects are discussed in a Yahoo Group called “Softrock40”. If you are having difficulty with your kit or want to discuss the kits in more detail it is strongly recommended that you use this group. This group generates a lot of message traffic so when you sign up be ready to receive over 50 messages a day (or sometimes more).
http://groups.yahoo.com/group/softrock40
You can also ask your question to Tony directly, but please try the yahoo group first. Tony does read and respond to messages in the group, but there are a lot of experienced folks who can help and that frees up Tony to do other things.
(RLD, 2009/01/22)
This section covers the available kits that we know about. This list is always changing so what you see here may be out of date.
(RLD, 2009/01/22)
Kit orders are currently suspended from 1/28/2009 until 2/16/2009 so Tony can get caught up.
This information is condensed from various posts from Tony in the Yahoo Group as well as the website that holds all the assembly instructions for the “official” Soft Rock kits available from Tony. Tony usually accepts payments though “PayPal” at his “KB9YIG(at)gmail.com” address. This information my be out of date by the time you read this so it is suggested that you check on http://www.golddredgervideo.com/wb5rvz for more up to date information and how to order or contact Tony directly.
|
Kit Name |
Price(*) US/DX |
Builder’s Notes |
Comments |
|
V9.0 Lite+USB Xtall |
44/45 |
http://www.golddredgervideo.com/wb5rvz/RX_V9_0/ |
With Manual BPF switching for 4 bands (1.8 to 30.0 MHz) |
|
V9.0 & Switched BPF for 1.8-30Mhz |
56/57 |
http://www.golddredgervideo.com/wb5rvz/RX_V9_0/ http://golddredgervideo.com/wb5rvz/hf_bpf/ |
Includes the V9.0 Receiver and the Electronically switched BPF in place of the manual switched ones. |
|
V9.0 & Switched BPF for 75-6 Meters |
56/57 |
http://www.golddredgervideo.com/wb5rvz/RX_V9_0/ http://golddredgervideo.com/wb5rvz/hf_bpf/ |
Includes the V9.0 Receiver and Electronically switched BPF in place of the manually switched ones. |
|
Switched BPF (80-6 Meters) |
14/15 |
http://golddredgervideo.com/wb5rvz/hf_bpf/ |
Electronically |
|
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|
Lite II |
10/11 |
http://golddredgervideo.com/wb5rvz/sr_lite_ii/ |
For a single band (80,40) |
|
Lite II Upgrade |
12/13 |
http://golddredgervideo.com/wb5rvz/sr_lite_ii/ |
Upgraded bands (30, 20, 15) with 1/3 subharmonic sampling with an OpAmp in audio stage |
|
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|
USB IC2 Interface Kit |
10/11 |
See the Yahoo Group for Documentation for this kit. |
USB control of Si570 frequency in existing V8.3 receiver |
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* Price is US & Canada/DX in US Dollars.
(RLD, 2009/01/28)
TBD
(RLD, 2009/01/22)
The following are software packages known to work with the current Soft Rock kits. (RLD, 2009/01/22)
It is highly
recommended that you start with Rocky!
This is most likely the simplest software to get running and most of us started with it. You can find it at: http://www.dxatlas.com/Rocky Tony explains how to configure Rocky in message 21692 in the Yahoo Group (you must be subscribed to view) http://groups.yahoo.com/group/softrock40/message/21692
(RLD, 2009/01/22)
RX:CW, PSK, SSB
TX: unknown
Power SDR is slightly more complicated to setup and use, but has a bit more flexible operation. PowerSDR is under active development so it is difficult to know exactly where to look for information. A google search is suggested, or ask on the yahoo reflector for information about how to configure this software for the Soft Rock.
http://groups.yahoo.com/group/powersdr-iq/
(RLD, 2009/01/21)
RX: CW, SSB, AM, FM
TX: CW, SSB
This software is available for download http://www.m0kgk.co.uk/sdr/index.php and is the creation of M0KGK. This software has it’s own Yahoo group which can be found at http://groups.yahoo.com/group/kgksdr/ if you want more information.
(RLD, 2009/01/21)
RX Only though I’m told it’s pretty good. Winrad doesn’t seem to be under active development at this time. You can find more information at http://www.winrad.org/winrad/
(RLD, 2009/01/21)
RX of DRM broadcast modes from a soft rock receiver.
http://sourceforge.net/projects/drm/
(RLD, 2009/01/21)
The choice of computers is largely one of what you can
afford. Generally the faster and more
memory you can get the better. Most of
us cannot afford the top of the line and have to settle for technology that is
a few years old, which is fine too. In
my experience, a lot more depends on what operating system you have installed
than how fast your CPU is. For most of
the software discussed above, you will do fine on a 1.4 Ghz CPU and 2 Gigabytes of memory running Window’s XP
or Linux. If you are running
(RLD, 2009/01/21)
The sound hardware is important to the effective operation of all audio based SDRs. If performance (sensitivity, dynamic range, noise, etc.) is important to you then you will need to be careful with your sound card selection. Of course it’s easy to spend a lot of money on a sound card and not get any improvement. At a minimum, you have to have a way to digitize stereo inputs to make use of most of the SDR software listed here.
Generally, there are two important considerations with sound cards. First is sample size or how many bits are used each time the analog signal is sampled. Usually PC hardware will provide 16 or 24 bits in a sample. You should use 24 bits for SDR applications which is unlikely to be a problem unless you are using a very old ISA based sound card that won’t do more than 16 bits. The second parameter you should look for is sample rate. Good sound cards can have up to 192 kHz sample rates, some won’t do 48 kHz very well. The higher the sample rate the better but only up to a point for two reasons. Some sound cards consume more CPU when running at higher sample rates and the increased sample rate makes the software work harder to deal with the extra samples. If you don’t have enough CPU power available to handle the extra load there is no point in having the extra samples. However, the higher the sample rate the greater the frequency spectrum you can see. (Generally the spectrum you see is ½ the sample rate of the sound card.) This means you need a sound card with 24 bit sample size and as high of a sample rate as your computer (and pocket book) can handle.
The following is a list of sound hardware information that is believed to be accurate but because manufactures of this stuff don’t check with us before they make engineering changes to their products, the information here could be incorrect for your specific card. M0KGK has an excellent discussion about noise performance at http://www.m0kgk.co.uk/sdr/soundcards.php that one should take a look at before buying a sound card.
By all means, let us know what sound hardware you have tried and what results you have had so we can report it here:
(RLD, 2009/01/21)
|
Card |
Cost |
24 Bit? |
96 kHz |
192 kHz |
Reports |
|
Creative Labs E-MU 1212M PCI |
$140 |
Yes |
Yes |
Yes |
Success with PowerSDR |
|
Infrasonic Quartet PCI |
$140 |
Yes |
Yes |
Yes |
Success with PowerSDR |
|
M-Audio Delta44 PCI |
$150 |
Yes |
Yes |
no |
Success with PowerSDR |
|
M-Audio Audiophile 2496 PCI |
$90 |
Yes |
Yes |
no |
Success with PowerSDR |
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(RLD, 2009/01/21)
Because of the CPU load that USB imposes on a computer, it is generally not recommended that you use a USB sound card on a computer that is not pretty fast.
|
Card |
Cost |
24 Bit? |
96 kHz |
192 kHz |
Reports |
|
Creative Labs E-MU 0202 USB |
$100 |
Yes |
Yes |
Yes |
Success with PowerSDR Recommend MultiCore CPU |
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(RLD, 2009/01/21)
|
Card |
Cost |
24 Bit? |
96 kHz |
192 kHz |
Reports |
|
Roland Edirol FA-66 Firewire |
$280 |
Yes |
Yes |
Yes |
Success with PowerSDR |
|
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|
|
(RLD, 2009/01/21)
|
Card |
Cost |
24 Bit? |
96 kHz |
192 kHz |
Reports |
|
SoundBlaster Audigy 2 ZS Notbook |
$100 |
Yes |
Yes |
no |
Success with PowerSDR (Used only) |
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(RLD, 2009/01/21)
This is version 0.2 of the FAQ and was released on January 22, 2009.
(RLD, 2009/01/22)
|
Date |
Version |
Changes |
|
2009/01/21 |
0.1 |
Initial Version |
|
2009/01/22 |
0.2 |
Re-Organized, Removed some stuff, Added Copyright notice. |
|
2009/01/26 |
0.3 |
Removed RxTx+Xtall V6.3 kit |
|
2009/01/28 |
0.4 |
Added The suspension of kit shipments |
(RLD, 2009/01/28)
This FAQ was started by R.L. Diepenbrock (KC4UAI) in an attempt to distill all the available information on the Soft Rock kits into one organized place. Many folks have assisted with this effort, some who are listed here:
(RLD, 2009/01/21)
The current overall maintainer is Bob Diepenbrock. PLEASE contact him directly at kc4uai@gmail.com with your suggestions, additions or changes.
(RLD, 2009/01/21)
Copyright 2009 by Robert Diepenbrock (KC4UAI@GMAIL.COM)
Permission is granted to copy, distribute and/or modify this document with the following terms: