This section describes the procedures for setting up your system to run sound card applications. You should select one of the programs in section 6 to use for testing and setup purposes. The examples given below are for the Hamscope program. This program is chosen because it provides both a waterfall and a spectrum display for monitoring band activity.

7.1 Load the Sound Card Program - Load the program and select "Settings / General Setup" at the top of the screen. Enter your callsign in the callsign panel, and enter the COM Port Number of the Serial Port used for PTT control.

Before you hook up your interface and rig, try out the program to get familiar with the sounds coming from it and the operation of the macros. Later on, once you get familiar with the operation of the software, you will probably want to customize the macros for your own operation.

7.2 Hook Up Your Rig - At this time, be sure that you have good ground connections to your PC the SSB rig and the tuner. Now, hook up the rig, interface and PC as shown in figure 7.1 below. Put the PTT control switch on the interface to the "Off" (center) position for initial tests.

On the Hamscope window, go to "Settings" / "Rx Level Adjust" on the control bar at the top of the window. This will bring up a window to allow you to set up which sound sources will be selected for processing by the sound card. Select "Options / Properties", set it to "Adjust volume for recording" and then click on all sources shown at the bottom of the panel. Click on "OK" and you will see the sliders for all possible sources for the sound card input. Click "Select" ONLY on the "Line" slider. This is the one that the interface is tied to. At this time, you can select "Options" again and unclick all of the sources except the Line In if you want to. Set the slider for about the middle of the range.

Set your SSB Rig to 14.070 USB (If your rig is LSB only, set it to 14.073 LSB). Listen for warbling tones on the frequency. If you hear tones, you should see signals on the waterfall display or the spectrum display. On the waterfall display, there should be a set of "tracks" going down the screen where a signal is being shown. You may need to adjust the Display Gain on the screen to see the signals. Set the Interface Rx Level Control knob to about mid range.

If you do not see signal activity on the screen, but hear tones, check your connections. If they are all right, take the interface card out of the box and look at the solder connections on the board to be sure that all connections are soldered, and no shorts are apparent. Also be sure that the rig is set up to send audio from the output connector you have selected.

When you see signals on the screen, set the AFC button on the Hamscope Receiver control and click on the center of the signal using the left mouse key. The top receive display should start printing data from the signal.

You may see a red warning on the waterfall to "Reduce Input Level". This indicates that the signal is too strong, and nearing the maximum dynamic range of the Sound Card. Use the Rx Level knob on the interface to reduce signal level on input if necessary. The best setting for the Rx Level knob is just under the point where you get the warning message. This will keep the maximum signal coming into, but not overloading, the Sound Card.

Other controls that affect the receive level are the RF gain of the receiver, and the receive volume control slider on the PC. The RF gain of the receiver can be used to reduce level of the

signal sent to the sound card. The best use of the RF gain is to reduce levels when you are copying a very strong signal on the waterfall. Reducing gain helps reduce some distortion when the signal is driving the AGC of the receiver. You will see in the next section, that the IMD measurement can be affected by these strong signals.

Take some time to monitor signals and get a feel for the style of QSO used on PSK31.

7.4.1 PC Tx Level Adjust - Go to the Hamscope Screen, and select "Setting/Tx Level Adjust". The volume control panel for the sound card volume control should appear. On that screen select "Options/Properties". The Button for "Playback" should be set. In the panel at the bottom, click on all of the sources so you can view their settings. Click "OK". The full Volume Control panel should appear, and should be similar to the view in figure 7.3, PC Tx Volume Control Panel, below.

The two controls not muted are: Wave, the control for the output level of the signal created by the Hamscope program; and Volume control, the general output level control for all sources. The combination of the two determines the actual output level sent to the interface and the rig.

If you like, you can now go back to "Options/Properties" and unclick on the view selections for all but the Volume Control and the Wave Control. This provides a smaller window, viewing only the activated sources.

7.4.1.2 Set the initial PC audio level - Set the sliders on volume control to the positions shown in figure 7.2. Volume around half, Wave around one third.

7.4.2 Getting Ready to Transmit - at this point you are ready to try transmit controls.

7.4.2.1 Reduce the rig power level and connect to a dummy load - It is a good idea to use low power and transmit into a dummy load during initial tests. Connect the transmitter to a dummy load, and set the output level control to around 5-10% of maximum.

7.4.2.2 Set the transmitter frequency - Set the transmitter frequency to USB, 14.070 MHz. The actual transmit frequency will be the combination of the SSB rig frequency (14.070), plus the audio tone created by the software (in the range of 200 to 2500 hz). The audio frequency is set by clicking on the waterfall at a particular audio frequency. If you are connected to an antenna, choose a point that doesn’t have a signal on or near it.

7.4.2.3 Transmit Audio offset should be between 800 and 2100 Hz - The waterfall shows signals from about 200 Hz to 2800 Hz above the frequency set on the rig. When you transmit, you should limit yourself to a tighter range, using offsets between about 800 to 2100 Hz. There are two reasons for this. First, your rig has a transmit audio passband that rolls off around 2100 Hz, Operating above that point will cause distortion. Second, don’t go too low, as the passband filter starts to roll off on the low end too. To work signals outside this range, move the rig frequency to get the desired signal in this limited range. Some software, like Digipan, has a waterfall width of about 4000 Hz, so be careful.

Some good news: There are some special single board transceivers built for PSK31 use which have a wider passband, so check your manual to determine your particular rig’s width. There are also some general purpose rigs, like the Pegasus, which have output audio passband which can be set up to 3900 Hz.

7.4.2.4 Set the Initial Transmit Level controls - Set the Tx Level knob on the interface to full CCW. Leave the PTT switch on the interface to the "OFF" position. Set the rig mic gain to about 20%. Set the PC TX Volume control and the Wave control to about 50%.

7.4.2.5 Set the Audio Monitor Level - Now, click on the big "RX" button on the Hamscope screen. It’s legend should change to "Tx". Normally you would be transmitting now, but we left the PTT control in the OFF position so everything is being performed except actually keying the rig. This lets you set up your monitor level without actually transmitting. You should hear a tone coming out of the PC speaker. It is probably too loud. Click on the "TX" button to turn it off.

Next, disconnect the left channel speaker on the PC, and go back to the Tx Level Adjust window in Hamscope’s "Settings". At the top of the Wave panel, there is a Balance slider that goes left / right. Slide the pointer to the left. This is an "attenuator" control for the speakers. Sliding it to the left attenuates the right channel, while leaving the left channel at full output. (The left channel is where your interface is connected). Turn on the "Rx" button again, and adjust the level of the tone in the speaker by moving the slider to the left until it is at the level you like. This is the advantage of using only one channel from the sound card. Click on the "Tx" button again to return to Rx mode.

7.4.2.6 Test the PTT - At this time, you should check that the PTT of the rig is operational. Move the Interface PTT control switch to the "On" position. You should see a transmit indication on the rig. Now, move the switch back to the "Off" position. The rig transmit indication should go off.

Now you are ready to actually try transmitting a signal to the dummy load. Put the interface PTT control switch to the "Auto" position, and click on the Hamscope "RX" button again. You should see several things. The PTT LED on the interface should come on, and the rig TX indicator should come on. The interface Tx Level knob has been turned to the lowest position, so there should not be any power showing on the meter of the rig or antenna tuner. Now rotate the knob clockwise toward the half way position. You should see the power level increasing up to the level you set the output gain control. The final step will be to get the right settings for the PC Wave level, and the microphone gain on the rig, such that the power is at the "normal" level when the interface knob is at the half way (straight up) position. Return the Interface Tx Level control to full CCW. Turn off the transmitter by clicking on "TX" button.

7.4.2.7 Power settings - A word about power settings. Your rig has been rated for SSB voice or CW operation, which run duty cycles of 50% or less. The digital modes are transmitting at nearly 100% duty cycle so you should not run your rig at more than one half the "rated" power level. If you have a 100 watt transceiver, run it at 50 W peak or less. Also, the PSK31 signals have multiple frequency content because of the modulation system. The audio path MUST be operated in the linear range when running PSK31. This means that you can NOT use the compression system, if you have one, and you should not operate at levels that use the ALC (automatic level control),

7.4.2.8 Adjust the Mic Gain and the Wave level - Move the Tx level knob back to CCW, and turn the output level control of the rig to 100%. From this point forward, you will be adjusting the power output level with the interface Tx level knob. Turn on the transmit signal with the Hamscope "RX" button again and slowly move the knob back toward the half way point. Use the peak reading setting on the power meter of the tuner or rig. Do not adjust the power above your half power point. If it is reached before the knob is at half way, reduce the mic gain on the rig until the knob can be set at straight up, producing one half rated output power. If you cannot reach the half power point when the knob is straight up, increase the audio level from the PC Wave control to bring it into range. The object here is to get the mic gain and the PC Wave gain settings to the point where there is adequate "head room" on the interface Tx level knob. Once you have the levels adjusted, turn off the transmitter by clicking on TX button on the Hamscope screen. You are now ready for your first QSO.

Note: Once the mic gain and pc audio level settings are set up, write them down so you can set them there again if they get moved. All Tx level setting done in normal operation is done with the knob on the interface. You will find that the output power at a particular knob setting will vary from band to band, and sometimes within the frequency range of the audio waterfall. That is the beauty of having the knob control on the interface - you will not have to change the mic gain or the PC Wave level very often, if at all.