Ham & DSP

Myself

I am presently trying to learn as much as possible (very little time, very little results) from digital modulation over radio. More especifically using DSP evaluation cards from Texas and Motorola. At the moment I am almost exclusively using them not programming, but I think that time will arrive.

DSP and HAM

There are several advantages using DSP:

The cost is low (comparing to standard Multimode Controllers).
It is easy to upgrade the software (no EPROMS to burn).
There is much software available with sources.
There are many modems available: VHF packet 1200/9600, HF packet 300, 1200 BPSK, AMTOR, PACTOR, RTTY/ASCII
There are many sound processing soft: CW/SSB Filters, autocorrelation filters, automatic notch filters

There are also disadvantages

If you don't program (as me) you are bound to the authors that kindly developed a modem to keep it working (mainly if he didn't release source code)
If you plane to employ unattended operation, you need to have a computer running all the time: Noise...
You must search a program available to your OS of choice...
Normally you must use a computer to load soft on the board.

What to use / Where to search

There is a place to begin searching about DSP and HAM, it is at Tuckson Amateur Packet Radio TAPR.You can take a look at it, or go directly to Digital Signal Processing Experimenter's Page. What follows is facts about the DSP Evaluation modules I have used. There are also applications on other DSP, but I haven't tried them.

One of the most advanced DSP used by Ham is the Motorola 56002 which is available in a low cost Evaluation Module named EVM56002 Board. There are applications for VHF 1200/9600 packet, 1200 BPSK packet, Rtty/Ascii, Amtor and Pactor (Tx/Rx on FEQ and ARQ), SSTV, Fax, and APT interfaces to Jvfax 7.1, and several nice audio filters. I really stable and win95 compatible Flexnet drivers (I have been told that these are being developed by the Flexnet group), and Pactor ARQ Tx. You can begin take a look here.
 

I have setup a server with almost everything mentioned here. It's manually updated (no mirror, for TAPR compliance), and is really meant for near users, as the link is very good with Spain, good with Europe and from bad to very bad to N/S America. The server is located at ftp://det.bi.ehu.es/pub/ham If you are the author of some soft and you want to update it, please, put it in the incoming dir of the same server and send me a message.
KC7WW Collection of EVM56K Applications
There is a new page only for EVM also at TAPR, it is at Motorola DSP56002EVM
DSP-4 is a board based on a Motorola 56001 DSP, much of the software available for the EVM derives from it and there is a good documentation about the implementation of 1200/9600 modems and filters. Take a look at vk4yeq page.
You can also check some articles (in Spanish) by Jabi Agirre EA2ARU and me.
• The first one is based on a Johan KC7WW article published in QEX. It's here
• The second one is the continuation of the first one. It explains how to link interfaces to the EVM, and a EPROM with several modems. It's here
• The third and last at present. Gives the absolute beginner a guide to put the board at work and how to modify the sources in order to adapt them to his interface. It's here.
There is for example, another source of soft and text for TI TMS320C25 and Morotola DSP56002 EVM is   Jürgen Hasch DG1SCR's page  DSPs for Radio Amateurs . Buried in this page, there is a flexnet driver for the EVM here . At present, it is experimental.
Doug's SV/N1OWU contributions have arrived. They include a DOS/Linux loader through  the SCI port (no more serial port switching). They are available primarily at  TAPR Dsp Recent Upload Area as n1owu_11.zip
There is some activity based on Linux this time by D.Jeff Dionne, he has some utilities as a loader, asembler and compiler available at ftp://ftp.pfnet.com/pub/m56k
Another area where there is activity is the use of high level languages for programming the EVM. Johan's work is available as cevm*.* in TAPR Dsp Recent Upload Area. He includes also information for preparing a memory expansion for the board, as C programming is very RAM hungry. Doug's is also going to put information about his work in this area.
Domain Technologies (the author of EVM56K...) has a server here
There are development tools and a nice free scope application here , at Tasking.
I have been told that Jabi Agirre is promoting a low cost radio-interface to this board and also offers the board at an agressive prizing.
There are now  several exciting new modes for HF that envolve working with weak signals. You can read an article by Johan KC7WW that compares both of them in his article  Recent HF Communications Advancements :
• One of them is PSK31, based on Pawel Jalocha's slowbpsk that has been reworked by Peter Martínez G3PLX. You can find technical details here.  It's a mode for HF keyboard to keyboard communication that is regularly used by several people both in Europe and USA.In it's present incarnation it includes Viterbi coding and QPSK modulation. You will find the following versions and more information in the PSK31 WWW Homepage :
• PSK31 for Texas DSK C50 with QPSK DOS Version by Andrew Senior G0TJZ
• PSK31 for Motorola EVM 56002 on DOS with QPSK  equivalent to the Windows SB and EVM versions. By Peter Martinez G3PLX
• PSK31 for Analog Devices SHARC Evaluation Board, Windows Version by Michael Keller DL6IAK
• PSK31 for Linux and SoundBlaster by Hansi Reiser DL9RDZ. Although it's not full-duplex, it comes with full sources.
• PSK31 for EasyDSP unit on DOS by Ulrich DF6JB. It's available here
• New version for Windows and SHARC EZ-Lite that adds to the "standard" modes variable transmission-speeds (PSK16-124 ) with stronger QPSK modes up to constraint length 9 by Michael DL6IAK: mpskwin.zip
• PSK31 for Motorola EVM 56002 on Windows Version 1.24 With help, tunnig aids, and a waterfall indicator for easier tunning and a receive overload indicator. New version with Soft-decision Viterbi, better squelch, better AFC. by Peter G3PLX.
•   New version (1.05) for Windows and NT and Soundblaster. By Peter G3PLX. Now with more help, bigger waterfall display for easier tunning and overload indicator, it sets the sample-rate better and can handle really way-off-frequency soundcards now: p31sbw105.zip
• You can hear these modes here: Note that these files will be correctly decoded if feeded on the DSP, that's why they are so lengthy. Note the preamble at the start and end of the transmission. If you only want to know how they sound, you can get the ADPCM compressed version (I haven't tested if they decode correctly)
• PSK31 in bpsk mode calling CQ. Compressed here.
• PSK31 in qpsk mode calling CQ. Compressed here.
• You can see also how much spectrum they use. These images have been obtained with EvmSpec.
• PSK31 in bpsk mode.
• PSK31 in qpsk mode.
• Peter G3PLX has published a very informative article (in english) in RADCOM magazine. Editors have agreed and we are able to read it here in PDF* format. It's here
• The other one is Coherent BSPK by Bill de Carle VE2IQ. This software is intended to be used with two fine boards (Sigma A/D) he produces. You can read an article by Lyle K0LR about Coherent BPSK here. Johan KC7WW has prepared an interface that let's you use Coherent with the EVM. Perhaps you will need to add some lines and level shifters to your interface. The interface is available here and the program is available at Bill's BBS. These are the schedules: 14.081 at 1600z weekdays, 18.081 at 1700z especially on week-ends and 1.881 at 0300z (Mainly USA roundtable). There is a new program from Bill called Africa and available at his BBS.
• You can hear how this mode sound. Take in count that Coherent is very configurable in terms of speed and coding, Here is Coherent on MS25 and ET 1 calling CQ. Compressed here.
• You can see also how much spectra does Coherent use here.

There is also a 64 Tone Paralell modem by Pawel Jalocha, that works very well under heavy QRM and QSB.. It's available here.
• Here is how MT63  sounds calling CQ. Compressed here.
• This mode uses much spectrum, you can take a look at it here.
• There is a Web page that shows how to use MT63 here
• There is a Beta Version of MT63 that offers several differences as CWID and variable bandwidth (500Hz, 1000Hz and 2000Hz). It's here. It includes an split window DOS Terminal.
There is also a 15 Tone Paralell modem by Pawel Jalocha, with an KISS/AX.25 interface that seems promising. Any test?. It's available here.
• Here is how QPSK  sounds sending a AX.25 SABM packet. Compressed here.
• This is a spectrum plot.
There are two new aplications by Peter Martinez, one is an audio spectrum analyzer EvmSpec that you can get here. And the other is general purpose loader that can be used to load applications from the command line and to let G3PLX applications automatically load the EVM. You need an ATMEL 29C256 eeprom. It's named PlxBoot and it's here.
Johan KC7WW has released a beta modem and associated program that implements PACTOR and AMTOR. I have tried it and it works. Soon there will be sources available. You will need the same modifications to the interface board as for the coherent interface. It's available here.
Dough  SV/N1OWU has prepared a Win95 package that implements Hell (an abbreviation of 'Feldhellschreiben'). It's rather amusing. There are nets in Europe on Sunday at 1200Z on 7035 and at 1400Z 10137. The package is available here. You can hear how it sounds here, note the idle dit-dit at the end of transmission: Hell calling CQ. Compressed here.
Murray ZL1BPU has prepared a nice page about Feldhell and similar modes it's the WWW page of  the Fuzzy Digital Modes. There are available there several programs including Mosaic2 by himself.
Read about new MTHell Record between ZL1BPU and EA2BAJ.
Finally we are able to use two packages by Peter G3PLX that implement a Windows Feldhell terminal and a Windows MTHell (Multitone Hell) terminal. Both are for the Motorola EVM.
• Here is how MTHell  sounds calling CQ. Compressed here.
• This is how you can read it with a spectrogram program like GRAM.
Jabi EA2ARU has prepared a AMPOP emulator (the hardware used with hamcomm and Jvfax). It's an alpha and read the doc as you perhaps will need to make some more connections to your interface to reroute signals as AMPOP compatible programs use.  It's available here.
Doug  SV/N1OWU  has prepared a new downloader for Windows95/NT it's dl32.zip.along with an EEPROM you can download files to the EVM using the serial conector on the EVM you also need a eeprom.
Here are several articles in German from Fred OH/DK4ZC about PSK31 and Feldhell
TAPR is just promoting a case and interface for the EVM56002 take a look at it here, hopefully it will be directly compatible with Dough's and Johan's software.
Jabi EA2ARU has just adapted several modems that Ulrich Bangert DF6JB coded for his EasyDSP Unit They should be used with the fine JvComm32 program  by  Eberhard Backeshoff that is available here . The modems itself are available here: AmFax95, FmFax95, Sstv95. Perhaps they could be adapted for other programs.
I have prepared two articles in Spanish about New Digital Modes on HF. One of them is a 2 pages article written and acepted for the Ursi98 Spanish Conference that you can download or view online in PDF* format here. The other one is longer and appeared in the December 1998 Radioaficionados Magazine and you can get it also in PDF* format here.
Doug has re-released a bios2.asm file that is compliant with TAPR EVM interface and that also has get rid of several small bugs.
Doug has released a modem for getting Differential GPS information from the Coast Guard broadcasts. I cannot test it in Spain as at this moment that service is not available here.

There is another DSP in use on Ham applications the Texas Instruments TMS320 family (the C26 and C50 families). As far as I know there are applications for VHF 1200/9600 packet, Rtty/Ascii, Amtor and Pactor (Tx/Rx on FEQ and ARQ !!!), Flexnet drivers, and several nice audio filters. I miss here the Jvfax 7.1 Interface You can begin take a look here.

Thomas Sailer, HB9JNX there are Rtty/Ascii, Amtor and Pactor terminal for C26 and C50 kits.
There are also drivers for these (C26 and C50) boards for Flexnet in the Flexnet page that along with the TFemu package give a TheFirmware emulation.
There is a new version of Andrew's PSK31 terminal for the C50 that does offers QPSK and Viterbi coding it's here.
Recently  Alberto di Bene  I2PHD and Vittorio De Tomasi  IK2CZL have prepared a nice program Dspbox for the C50 kit that converts it in a notch, denoiser, passband and automatic AGC DSP box. It's really awesome, take a try. A new version that works flawlessly on fast computers has been released. It's here.

There is another DSP, the Analog Devices 21000 SHARC Family, that is begining to have use in HAM by the hand of Michael Keller DL6IAK. He has just developed a PSK31 version for this platform, and he has also been working on a RTTY modem for it.
 

Miscellanous

Sites that are worth to take a look

Association Pages
RadioClub de la Escuela de Ingenieros de Bilbao
AMSAT-EA Homepage
Tucson Amateur Packet Radio (TAPR) Home Page
American Radio Relay League (ARRL) Home Page
Radio Amateur Satellite Corporation, North American branch (AMSAT-NA) Home Page
Unión de Radioaficionados Españoles (URE) Home Page
Digigrup EA3 Home Page
Flexnet Homepage
Individual Pages
Phil Karn, KA9Q One of the more envolved hams in Digital Signal Processing
Thomas Sailer Thomas has many interesting pointers and he is one of the fathers of Flexnet.
This is Johan Forrer's KC7WW Homepage. It's worth a look.
Michael Keller's DL6IAK Homepage
Doug's N1OWU Homepage
Gram Homepage
There is a very interesting page by Oliver Welp listing SB Software for Ham
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