DigiPan.RTF              Digipan Help for Version 1.6              Page of

Equipment Setup

Receive Audio Connection

Connect an audio cable between the transceiver audio output and the soundcard LINE IN jack. The audio output of the transceiver may be the speaker output, an auxiliary audio output, or an earphone jack. It is best to use a transceiver audio output that is unaffected by the transceiver volume control if available.

In case the audio output of the transceiver is too low to produce a blue speckled background on the DigiPan Spectrum Window, change the connection at the soundcard end of the cable from the soundcard LINE IN jack to the soundcard MIC jack.

Receive audio level is controlled by the DigiPan Receive Volume and, if coming from the transceiver speaker or earphone audio output, also by the transceiver volume control.

Set the soundcard for the best sample rate conversion quality for the sharpest  possible display of received signals. DigiPan works best at a sample rate of 11025 Hz or higher.

Transmit Audio Connection

Connect a shielded audio cable between the transceiver MIC input and the soundcard LINE OUT jack through a 40 db attenuator, consisting of a 100K series resistor feeding a 1K parallel resistor. This attenuator will reduce the soundcard LINE OUT level from about 1 Volt down to the normal MIC input level of about 10 millivolts, so the higher soundcard output level does not overdrive and distort the transceiver MIC input.

If the transceiver is equipped with a high-level auxiliary input, then the attenuator is unnecessary, and the transceiver auxiliary input may be connected directly by shielded cable to the soundcard LINE OUT. If using the auxiliary input of the transceiver, be sure the transceiver microphone is disabled when operating PSK31, to prevent illegal modulation of the transceiver in the CW band by sounds picked up by the microphone!

T/R Connection

The transceiver’s VOX can theoretically be used to control the transmit/receive function, however it is often difficult to adjust for reliable operation while still maintaining the proper audio levels needed to preserve an undistorted PSK output signal. For this reason, Digipan provides for positive control of the transceiver’s PTT via the RTS and/or DTR  outputs of the computer’s RS-232 serial port.

The RTS and DTR outputs of the serial port are not directly compatible with the PTT control of most transceivers. The serial port outputs +12 to +15 VDC for transmit and –12  to –15 VDC for  the receive condition. Transceiver PTT circuits on the other hand, generally require a ground for transmit and an open circuit for receive. For most modern solid-state transceivers, a simple NPN switching transistor (2N2222 or equivalent), with a  2.2K resistor inserted in series between the base and the serial port, emitter connected to ground, a diode connected between the base and emitter (to prevent the –12 to –15 VDC from reaching the transistor), and the collector to the transceiver PTT line will suffice.

Connect a cable from the computer RS-232 connector to the transceiver PTT line, through a switching transistor as described above, using pin 7 or pin 4 if a DB-9 (small) connector, or pin 4 or pin 20, if a DB-25 connector (large).

In case there is no voltage available at the transceiver PTT input, try connecting the coil of a 12 volt, 1020 ohm, sensitive reed relay between ground and the output of the RS-232 connector, with a small signal silicon diode in series with the RTS or DTR output and the relay coil, cathode to the coil, and using the relay contacts to operate the transceiver PTT input. Also connect a small signal silicon diode in parallel with the reed relay coil, with the anode connected to the ground, in order to absorb any "inductive kick", or transient, created by the relay coil when de-engergized.

Transceiver PTT operation can also be switched manually if necessary.

Software Adjustment

After connecting the RS-232 port to the transceiver, the correct serial port must be selected in DigiPan, under Configure/Serial Port, and the "RTS as PTT" or "DTR as PTT" box checked. Since the internal modem, or other device, of the computer may be using one of the serial ports, it is necessary to physically connect to an unused serial port and then select that same serial port in DigiPan. DigiPan will send a PTT signal to either RTS or DTR, or both, so either one can be used for PTT. However, your cable wiring must agree with your PTT selection.

Troubleshooting

In some installations, ground loops on receive or transmit, or RF feedback on transmit, may cause problems in reception or transmission. In these cases, it is sometimes helpful to isolate one of both of the audio lines connecting the transceiver and the soundcard with a 1:1 audio isolation transformer to break the ground loops or even help keep unwanted RF out of the audio lines. Feeding the audio lines through small ferrite beads as RF chokes is often helpful in reducing feedback caused by RF on the lines.

Sometimes, simply muting the Microphone and Line inputs on the Windows Volume Control panel, which controls the sound fed to the computer speakers, is enough to stop audio feedback. In this case, never mute the Volume or Wave level controls, or the soundcard audio that is generated for transmitting will be shut off. Only mute the Microphone and Line controls, which will then make it necessary to use the transceiver audio system for monitoring the band by ear, as the receiver sound will no longer be passed to the computer speakers. However, since DigiPan is a visual method of reception, actually hearing what is happening on the band is only seldom necessary.

Setup

General setup:

Connect your transceiver to the soundcard and a serial port (for T/R switching) as described in Equipment Setup.

Under Configure/Personal Data, enter your Call, the Name you use on the air, and your QTH. Fill in the CW ID information and check Use CW ID  if you want to activate it.

Under Configure/Waterfall drive, adjust the appropriate Windows Recording Control level controls for a speckled blue background on the Spectrum Window, which is the window on the bottom of the DigiPan screen with the calibrated scale across the top, as described in Setup. If you are using Windows 95, to get to the Recording Control window, select Options/Properties/Adjust volume for recording and press OK. Be sure either Microphone or Line level controls are checked for display.

Press the T/R button on the Control Bar, which is the one with the twelve buttons at the top of the DigPan screen.Under Configure/Transmitter drive, adjust the Volume and Wave level controls for undistorted RF output as described in Setup. Press the T/R button again to stop transmission and return to Receive mode.

Setting up the DigiPan dial scale to read actual transmitted RF frequency:

Under Configure/Band, mark the band you wish to be displayed on the dial scale as active, tab to the Spectrum Start box and enter the Spectrum start frequency in kHz, or kHz and tenths of kHz, and check if you want the dial scale to display the Tone frequency, USB, or LSB. If you select USB, the Spectrum start frequency to enter is the low end of the band segment you want to cover and if you select LSB, it is the upper end of the band segment. It is important to note that the Spectrum Start frequency is the "zero beat" frequency, which is the same as the transceiver dial setting, so it is suggested that the Spectrum start frequency, and accordingly the transceiver dial, be set about 0.5 kHz away from the first desired frequency of operation.

As an example, for 20 USB meter operation starting at 14070,

Enter 14069.5 as the Spectrum start frequency.

Set your transceiver dial to 14.069.5 MHz and DigiPan will tune from 14.069.5 MHz

to 14.073 MHz for you. Do not touch the transceiver dial after setting it and the DigiPan dial scale will read correctly. Assign the frequency to a memory if you have one. Use the widest IF filter available. If the IF filter is 3.5 kHz wide, stations between 14.070 and 14.0730 should be workable. If the IF filter is only 2.5 kHz wide, stations between 14.070 and 14.072 will be workable. Even though it may be possible to copy strong stations somewhat outside the filter bandwidth, attempted transmission too far from the filter passband will usually result in operation at greatly reduced power levels.

If you need to use LSB, check LSB, set the transceiver to 14.073 MHz, and the Spectrum Start frequency to 14073.0 kHz, and DigiPan will tune down 2.5 kHz or the width of the IF filter for you.

DigiPan will remember the dial scale settings you enter, so when you change band, it will usually only be necessary to select the active band and the dial scale will read correctly.

You can edit the default Band and Spectrum start frequency to any band and any frequency and the DigiPan dial scale will read correctly, as long as the frequency is entered in kHz.

Just remember to always set the Spectrum start frequency and the transceiver dial frequency to the same value and select the same sideband on each.

Feedback problems

If you experience audio feedback on Receive, try muting the Microphone and LINE inputs by checking the mute boxes on those controls on the Windows Volume Control panel, which you can access under Configure/Transmitter drive, or by double-clicking on the speaker icon in the Windows system tray. Do not mute the Volume or Wave controls, or you will not be able to transmit. You will not be able to audibly monitor the band using the computer speakers, but DigiPan uses the Recording Control panel to adjust drive to the spectrum display and will function normally. Depending upon your equipment setup, you may still be able to monitor the band using the transceiver speaker.

Receiving PSK31

Single Channel Operation (Channel A)

PSK31 signals display as two parallel lines, resembling railroad tracks, in the Spectrum Window. Tune in a PSK31 signal by pointing to it with the mouse and clicking the left mouse button. The text being sent by the station will then appear in the Receive Window, which is the largest window, near the top of the DigiPan screen.

In this screen capture of a portion of the Spectrum Window of an actual DigiPan screen, the bright yellow-green stripe with the diamond-shaped cursor in the middle is a strong PSK31 station, the one to the left is a weak PSK31 station, but still printing perfect copy, and the faint signal to the right is a PSK31 station that is too weak to copy enough to sustain a QSO. The short trace between the two is a carrier that has already left the air, and the very faint signal to the far left is a weak PSK31 station that has just quit transmitting.

The diamond-shaped cursor has been placed in the middle of the strong signal by pointing to the signal and clicking the left mouse button, and indicates the station that is currently being printed.

It is also possible to move the diamond-shaped cursor for tuning using only the keyboard by holding down Ctrl and pressing the left or right arrow key.

Stations may also be tuned in by assigning the <SEEKLEFT> and <SEEKRIGHT> macros to individual function keys, preferably single-finger keys. Pressing the key assigned to <SEEKRIGHT> will cause the cursor to jump to the next signal to the right of the current cursor position. Pressing the key assigned to <SEEKLEFT> will cause the cursor to jump to the next signal to the left of the current cursor position. Seek will send the cursor to any signal strong enough for Seek to detect, so if the cursor stops on what appears to be an empty frequency, it may have detected a noise pulse or spurious signal instead of a station. Just continue to press the Seek key repetitively until the cursor stops on the desired station. If the cursor seems not to move, there may not be a detectable signal in the direction of Seek. It is important to always select the proper sideband in use, through the Band menu configuration, in order to make Seek move in the proper direction. If Seek passes the station you want to tune, or tunes to one side to the station and not in the middle, just press the Seek button to pass the station and approach it from the other side. The default keys for Seek are F11 and F12, labeled << and >>.

When Options/Arrows for Seek is checked, the left and right arrow keys can be used for the Seek function, releasing F11 and F12 for other one-finger macro key configurations. However, if the left and right arrow keys are used for Seek, they are not available for editing the TX and RX windows. You need to decide if you prefer using the arrow keys for Seek, or for editing the TX and RX windows.

When Options/Continuous Seek is checked, Seek will search continuously for a signal and stop when it finds one. To manually stop Continuous Seek, just press any Seek key.

If Digipan is tuned to a station, and Squelch is not set too high, and no characters are displaying on the screen, the cursor may have been left in the RX screen from a previous operation. Just press the Tab key to place the flashing text cursor in the TX window and characters should start displaying on the RX screen again.

A place-holder called a Bookmark is available on the spectrum display. To place a bookmark at the cursor position, click the Mark button, or hold down Ctrl and click the left mouse button. A numbered bookmark will appear at the diamond cursor position at the bottom of the Spectrum Window. Pointing to any bookmark and pressing or clicking the Mark button, or holding down Ctrl and clicking the left mouse button, will remove a bookmark. To return to a bookmarked frequency, point to the numbered bookmark and click the left mouse button to position the diamond cursor there, or click the right mouse button to position the triangle cursor there.

When the Bookmark macro is assigned to a key, pressing that key will place a bookmark at the diamond-shaped cursor's position and if a bookmark is already placed there, it will remove the bookmark. DigiPan uses the name Mark for the bookmark key, as "Bookmark" is too long to fit on a key label.

In order to use bookmarks, you must have Bookmarks checked under the View menu selection. The bookmarks are numbered from 1 to 10 in the same order they were created. One way bookmarks are helpful is to mark the location of a station that has not yet transmitted a callsign, while checking another station of possible interest, and being able to easily return to the first station of interest. Bookmarks are also helpful in marking where you have been transmitting and wish to attempt to QSY by transmitting on another frequency, but return to the original frequency in case the other station did not hear you on the second one. The usefulness of bookmarks is only limited by your imagination! Bookmarks only work with the diamond cursor.

Dual Channel Operation (Channel A and B together)

Double-clicking the right mouse button in the spectrum wi...