SOFTWARE FOR HAM RADIO OPERATORS

Here are some links where you can download the best software for your HAM RADIO needs:

SSTV Software Selection Guide by John Langner.

Amateur Radio Soundblaster Software Collection

(by Oliver Welp, DL9QJ)dl9qj@amsat.org

Packet Radio

RTTY

Multi Mode

Fax (Amateur and Weather Fax)

SSTV

CW

Voice Tools

Recording Tools

ZVEI, DTMF & More

ACARS

Analyzers & DSP

Miscellanea

DETAILS BY: Oliver Welp, DL9QJ

Sound Card:

Many of these programs use a direct access to the sound card hardware, thus so-called "Soundblaster compatible" cards often will not work. So use an original Creative Labs Soundblaster card (Pro, 16, 32 AWE, 64 AWE) whenever possible. That does not mean that your compatible card will not work at all; it depends on the program. Some programs will work with many cards, some only on original SBs. Just try, but keep in mind that you may encounter problems.

Always install the latest driver available, since older drivers might contain bugs. - Some programs (e. g. W95SSTV, ChromaPix) that run under 32 bit operating systems (Windows 95/98, NT) may require a 32 bit sound card driver. Even a driver for Windows 95/98 does not automatically have to be a 32 bit driver - sometimes it is a 16 bit driver and you will not even know.

Do not tune the input and output volumes to its maximum, 1/3 usually is enough, larger volumes can cause distortion since the audio amplifiers on sound cards are not quite linear.

Connections:

When using the "Microphone" input of the sound card, the signal will be lead through the microphone preamplifier. So do not use the "Microphone" input since this can cause distortion - always apply signal to the "Line In" input. Same is applicable for the output; use "Line Out" instead of the "Speakers" output.

When connecting to the radio, usually a direct connection will work. If you encounter problems with hum or others (noise caused by the computer etc.), try an audio transformer or a capacitor in the signal path to avoid galvanic connection. Consider the impedance of the sound card and your receiver / transmitter.

At the receiver, use a fixed level audio output e. g. for tape recording, if your receiver has such an output. If not, use the audio output but tune it to about 1/3 of maximum volume - more can cause distortion. High speed data (such as 9k6 packet radio) will need the connection to the discriminator output of the FM chip, the normal audio output will not work.

Transmitting:

If the program has transmit capability, the radio needs to be switched to transmit mode. Sound cards do not have a PTT (push-to-talk) output, so additional hardware might be neccessary. Many programs use a simple device like the DSR or RTS pin of a serial port to switch the PTT, this signal will switch a transistor which sets the PTT input of your radio to ground level. Please read the programs documentation to see what device will be neccessary. Sometimes (when fast switching is not required) an audio Vox circuit or the Vox of your radio can do the switching.

Oliver Welp, DL9QJ, dl9qj@amsat.org

UPDATED: September 2001