Olivia MFSK Ver

DominoEX v1.0 Build 18.12.05, MFSK, with RIGblaster

(DominoF/G/EX by ZL2AFP)

Developed for ionosphere made distortions, weak signal QSOs. Bandwidth = 262 Hz – 18 Tones

A much abbreviated setup and operating guide, simplified to encourage those who maybe scared off by complexity.

Hardware:

A RIGblaster (1ea), Soundcard speaker cables: Radio Shack-42 2387 (3ea)

RIGblaster:

Strap P1 to match your radio's Microphone. (i.e. RJ45 IC706 page 9). Set Audio Level

Control full clockwise. Swith VOX/AUTO to AUTO, apply power. Cable RIGblaster to

radio and computer, as shown in RIGblaster manual’s hookup diagram, (PC Speaker Out to Rigblater In; PC Min In to

Rigblaster Out. The RIGblaster interface will allow computer speakers to continue to operate for music etc.

Note: Don't use low impedance un-amplified speakers.

Domino software Downloads:

DominoEX program: http://www.qsl.net/zl1bpu/domino/index.htm

Domino Help File: http://www.qsl.net/zl1bpu/domino/index.htm

Install to Domino folder:

Create a shortcut Icon and Reboot computer

Windows Sound card setup:

Master Volume: Master Volume to 1/3 of the way up - Balance slider to the center

Wave Volume to 1/3 of the way up - Balance slider to the center

Line In Volume to 2/3 of the way up - Balance slider to the center

Microphone Volume to 1/3 of the way up

PC Speaker Volume to 2/3 of the way up

Recording Controls: Line In SELECT - Volume to 1/3 of the way up - Balance slider to the center

Note: Turn the computer speaker volume control knob most of the way, but not all of the way down.

Radio setup:

Set all IF Filters to OFF (or as wide as possible)

Set Audio RF to MAX

Set VFO to: 14.107.5

Set Transmitter output power to ¼ manufacturer’s rated RF power output, 25 watts or

less is a good operating setup to provide linear performance.

Set Mode to USB (convention)

Set Processor to OFF and SWR and ALC ON

Speak into the Mic., adjusting Mic gain so that ALC doesn’t occur above the ALC Zone indicator.

Adjust Tuner for 1:1

Set ALC to ON and SWR OFF

Click on TX now button (transmission starts).

Adjust RIGblaster Audio Level Control, stopping as transmitter output power reaches MAX

(ie. 25 watts) keep an eye on your ALC so that ALC does not occur; run with NO ALC

indicating occurring; any ALC indicating, results in your TX Signal being distorted,

and causing harmonics.

Click RX to Stop TX

Note: The RIGblaster Audio Level Control is the most precise way to adjust the

Soundcard output voltage into the radio. The Microsoft Volume controls were

designed to vary the voltage, through a range of reasonable outputs for Speakers;

They were not designed to be adjusted so precisely as to be reliable set to

5 millivolts.

ALC can remain (on) to control drive limit.

Recommended frequencies:

3.683 3.880 7.079 7.080 7.105.5 14.078 14.107.5 18.107

To Operate:

Click on DominoEX Icon

Click DominoEX Icon

Click Mode – Select 11 baud

Click Options:

Type CALLSIGN – Received Text Character Set All 256 ASCII – PTT COM1 – Symbol sync a little sync average –

Keyboard Normal

Click Tools:

Squelch 5 – BW 122 – Input atten. 1 – AGC 5

Set Macro Buttons 1 to 10

To Transmit:

Type message in TX window and click TX now (message is sent)

Click STOP to PAUSE transmission

Click RX now (goes into RX)

Click RX to END (EOT)

The speed can also be identified by the apparent bandwidth on the waterfall - for example about 200Hz for DominoEX 11, and about 300Hz for DominoEX 16. If the speed is set incorrectly, the waterfall will be blurry, with dots of uneven brightness, and the problem obvious. Tuning is easy. Just keep all the signal between the two yellow lines, one in the middle and one at the bottom of the waterfall display, either by tuning the receiver, dragging the tuning scale to the left of the waterfall display, or dragging the display itself.

Three tuning displays are provided. The largest and most obvious is the Waterfall Display, the upper-most of the group on the right of the Receive Window. This indicates the signal tuning, and the quality of the received signal. Because the DominoEX Waterfall is synchronous with the signal, it will give a very sharp and clear display if the signal is of the correct type, and will be slightly blurred if it is not. Each little white dot (domino pip?) represents a burst of tone, or symbol. The scale on the left is frequency, in Hz, and changes when the mode is changed. The bottom of the scale (by default 1000Hz) is set by sliding the waterfall with the mouse.

The waterfall clarity is superb - you can always see the signal, even if it is very weak. The DominoEX example to the right was recorded with the signal 10dB below the noise in a 3kHz bandwidth, and the signal can be tuned by eye down to -15dB! Most other digital mode software is very difficult to tune with the signal below the noise, because you can't tell signal from noise.

The waterfall image moves left to right with time, and can be dragged up and down to tune the signal. Two yellow lines are visible on the display - one in the centre of the waterfall, the other right at the bottom of the waterfall. If all the signal falls between these two yellow lines (which are preset to indicate the receiving range), then the signal will be decoded correctly. It does not matter where in this window the signal falls, or if it drifts (provided all of the signal stays within the yellow lines). This gives you up to 200Hz of tuning latitude.

When there are significant problems caused by multi-path reception, the distinct little white stripes will show broadening or transient effects. When this becomes quite marked, copy will suffer, and a slower mode should be used. As the signal gets weaker, the noise background becomes more obvious, but you will be able to easily tune any signal that could be copied.

Below the Waterfall Display are two small Sync Displays. Their main purpose is to illustrate received timing variations. They can be useful when considering using different speeds. On the left, a cumulative indication of symbol sync versus time is shown. This is useful as an indication of multi-path reception, and the sync can often be seen to change abruptly when there is a fade. This display moves from left to right, and illustrates the tips of the sync triangle in the time domain. A bright green band indicates the centre of each successive symbol, as the display slowly moves along. Ragged upper and lower edges indicate multi-path reception. Fades will show as a darker or narrower section, followed perhaps by a vertical shift in the green band. There will also be a vertical shift in the green band whenever reception starts and the new signal is acquired. The height of this window is equivalent to the length of one symbol (1/baud rate).

On the right, below the Waterfall, the instantaneous Sync Display shows how each symbol is interpreted. A triangular green line with the apex uppermost indicates where the receiving software has determined the centre of the current symbol to be. This indication changes quickly with propagation changes. The red vertical line indicates the average receiver symbol clock position, i.e. the average of the peak in the green line. Sync tracks very quickly and is not affected greatly by noise.

The receiver signal level should be adjusted so that this display shows a full-height green triangle, perhaps a little flattened on top, but not too flattened, and not too small, preferably at least half the maximum height. This is best adjusted using the sound card Recording Control applet level control rather than the receiver audio gain. The height of the green line will change with signal strength, but operation is not fussy as the software has excellent AGC.

Characteristics:

DominoEX is a computer-based radio mode intended for chat-mode operation on the lower HF bands. You can use any SSB transmitter, even an old "steam radio" type. DominoEX has been designed to get around several problems which exist with other digital modes, such as difficult tuning, slow response, and poor performance on the 80 - 30m bands. It is so robust that FEC is not required. The new mode is so 'slick' that it would be useful for contesting. It is great for nets - it's as slick as RTTY, faster, and far better!

The all-new 'DominoEX' replaces the older DominoF experimental mode. The two modes are not compatable.

DominoEX is a digital mode with MFSK (Multi-Frequency Shift Keying), used to send data (for example, hand-typed text) by radio. MFSK sends data using many different tones, sent one at a time. Each tone element ('symbol') can carry several bits of data, unlike most other modes, where each element represents only one bit. Thus the symbol rate is much lower for the same data rate when MFSK is used. This is beneficial, since it leads to high sensitivity with good data rate and modest bandwidth. MFSK is ideal for HF operation as it also has good noise rejection and good immunity to most propagation distortions which affect reception of other modes.

MFSK is used on HF by modes such as MFSK16, ALE, THROB and Olivia.

The MFSK technique has a few limitations. The main disadvantage is that radio transceivers with high stability and tuning accuracy are generally required, since very narrow frequency differences are used. MFSK is also prone to interference from data arriving from different ionospheric paths (although less so than other modes), and prone to interference from fixed carriers within the data passband. With Forward Error Correction (FEC) deployed to reduce errors, these modes can become slow and clumsy to operate, or consume excessive bandwidth. In DominoEX, all the inherent MFSK problems are avoided or much reduced.

Digital mode approval: http://www.arrl.org/FandES/field/regulations/techchar/

References:

http://www.qsl.net/zl1bpu/domino/index.htm

Test equipment software:

Audio Signal Analyser: SpectrumLab v204b29 (speclab24b29.zip) www.xs4all.nl/~nl9222/software.htm

Oscilloscope, Dual-trace: WinScope 2.51 ( osc251.zip) www.electronicsaustralia.com.au/cgi-bin/downloads.pl?area=5

Spectrogram v5.0.8 (gram517.zip) http://neasmn.org/ben/software/software.htm

Spectrogram v4.2.6 (gram426.zip)

Analyzer 2000 v5.04 (Pay for) www.dxzone.com

MUF Charts: http://www.arrl.org/qst/propcharts/

DX Spots: http://hamcall.net/dxspots

DX Summit: http://oh2aq.kolumbus.com/dxs/