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 Try working 3B9C on some new
modesby Don, G3BJ 3B9C will be active on most modes. We will be using RTTY, PSK and SSTV as conditions and activity allows, and certainly will be making efforts to give everyone who wants a QSO on these modes the chance to work us. If you do not currently have equipment for these modes, do not worry ! Following these guidelines will give you an excellent chance of working us. For all three modes, you will need some form of data terminal. Nowadays, this is almost always provided by a computer running one of the readily available software packages, which provide access to all three of the modes above. Excellent ones include MIX-W and the MMHAMSOFT suite which is freeware. For PSK and RTTY, almost any computer running a modern version of Windows will suffice. For SSTV, you will need a fairly fast computer (probably in excess of 500 MHz clock speed). After you have loaded the software, you will need to interface your computer to your rig. The MMHAMSOFT site gives details of this. In short, using the sound card input and output, you should: a) Connect the AF line output from your rig (most transceivers have a low-level audio output at the rear, which is independent of the AF gain control) to the sound card input, using screened cable. b) Connect the sound card output via a 40 dB attenuator to the Mic input of your rig, using screened cable. A simple attenuator is: From sound card o/p 0----------/\/\/\/\/\/\/---o--------------> to Mic input 100k ohm | | 1 k ohm | To ground <--------------\/\/\/\/\/\/---o Set your transceiver to “USB”. Now you should be able to receive PSK, RTTY and SSTV ! Try listening to the frequencies for these modes – start with 20m and listen for RTTY around 14085. RTTY is a “jingling” sound, with a clear difference between the two tones. PSK will be found nearer 14070, and is almost a steady tone, with a slight “warble” on it.  Use
the “Waterfall” display on your software to check the tuning of your
receiver – most software allows you to point to the signal on the waterfall,
and click the mouse to “tune” the sound card to that frequency. You should
soon be receiving copy on both modes.Then you can try transmitting – first turn the speech processor off ! Then click the “TX” icon and away you go – but be careful – you must limit the power output of your transmitter to about 35% of the PEP power rating – so for a 100 w pep transmitter, use no more than 35 watts RF out on any of these modes. You can adjust this using the Mic gain control. A little practice will result in easy QSOs on these modes, but you need to get that practice in before trying to work 3B9C – as there is more to learn ! 3B9C will be working split – this means that you will need to transmit above our frequency. For PSK and RTTY 1-5 kHz is probably the best choice – listen on the “B” VFO to hear where everyone is calling, and use the split facility on your transceiver to call us. Alternatively, some software allows you to select a different transmit frequency simply by instructing the sound card to “split” but you may not want to bother with this approach. SSTV is a little more complex. Once you have loaded the software and interfaced the rig as above, try listening around 14,230 kHz. Most of the time you will hear a rhythmical “sloshing” noise, which you should be able to tune in using the spectrum display on your software to result in a picture. Remember SSTV picture transmission takes a long time – it is transmitted one line at a time in a 3 kHz bandwidth, so be patient. It takes time to be able to tune in an SSTV signal. Once you have the knack, it is time to prepare to transmit. But you will need some pictures, or at least a message. Your software allows you to prepare a basic message, which could be: 3B9C de < your call > Pse K You will also need to prepare a second message which is your report. SSTV uses a 5-9-5 scale for signal reporting, so if 3B9C is a fully readable signal, your report could be : 3B9C de < your call > Rgr UR 595 de <your call> If you have a digital camera, or some digital images, you can use these as the background for your messages. But again you will need to practice – so try a few SSTV QSOs before you try to work us, and importantly, get used to the “style” of an SSTV QSO ! Again we will be working “split” (see above) but the split will probably be up to 10 kHz – so listen around above our frequency to find a good spot ! Good luck ! |
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