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©2010 SMARC
Digital Notes
by Lynn Lamb, W4NL
  • RTTY is in LSB
  • PSK31, PSK63, Domino, MFSK, and Olivia are in USB
  • PSK31 is slow, but takes little space
  • PSK63 developed by KH6TY is fast, wider and I feel in time will replace RTTY
  • Domino has several speeds (i.e. EX-11, 8, etc.). The lower the number the slower, but better under bad conditions, especially QRN. It’s the mode of choice for those developing UHF/VHF traffic nets.
  • MFSK is good; a bit harder to tune, but excellent. Wider than PSK31/63.
  • PSK125 and 250 are new, very fast and interesting. Great for moving large amounts of traffic if conditions are fairly good.
  • I find PSK31 is the most popular digital mode for chatting and some DX. RTTY has been around the longest and is popular all over the world, and currently the choice for DX work. It’s of course wider than PSK modes, but still much narrower than SSB.
  • Lower power is necessary for digital modes although RTTY can and does require more power for the same results. Twenty to 40 watts is generally sufficient for PSK31, etc., while 100 to 200 watts is fine for RTTY. Keep in mind many want to run more on RTTY which is okay, but it detracts from others relative to the QRM generated. I find 10 watts will shock most in all digital modes.
  • Put effort into antennas/coax versus power. A balance is wise between power and antennas.
  • Attic or stealthy antennas are very popular with the digital modes and create a challenge which motivates me and others. Anyone with lots of room can do well, but where is the challenge?
  • There are audio levels to contend with using the digital modes, i.e. computer output levels (speaker) which goes into the mike input of the transceiver. Once set it should be fine. The problem is we use the same transceiver for SSB. If a separate rig can be setup for the digital modes, it’s much neater.
  • Always cut off any audio pre-emphasis such as speech processing in the digital modes.
  • You will want to monitor your outgoing signal which means your monitor level needs to be adjusted, and another reason for a separate rig.
  • Older rigs work very well with most of the digital modes. Don’t let folks concern you relative to drift. Frankly, I never have seen a problem with older rigs in this regard. We have knobs!
  • There are two main ways to hook up the rig and computer: One is with two simple cables with the 1/4" general available at Radio Shack and fests, and go between the back of most of the last two or three generation rigs or the mike connector. In other words the audio in to the transmitter from the speaker out of the computer. The other is from the speaker from the rig (a ‘y’ is fine to use to connect to the mike or line-in of the computer. If you use this method the VOX gain/delay will need to be adjusted from the normal SSB levels. This is generally easy. That’s it for simple way. Don’t let others make it hard. They will!
  • The other way is to use an interface with ‘rig control’ either from the serial or USB on the computer and the other end of the interface to the rig of course. There are several good ones available. This will allow the rig once the proper port is set to turn the rig on and off with the software such as FLdigi, MixW, Digipan, MMTTY, etc. There are no levels to adjust for rig control generally. Easy.
  • Some general rules at present for where is the action on the bands are:
    160 meters: at the very bottom of the band and little activity but growing.
    80 meters: GENERALLY….3.570 up to 3.600. Listen for your mode. I find most around 3.580. I like 3.575.
    40 meters: 7.035-7.045 and around 7.080. Need a band plan!
    30 meters: This is a surprise to many, but 30 is a SUPER digital band. 10.130 to the top of the band 10.150.
    20 meters: Around 14.070 for PSK31 and slightly higher for the other digital modes such as Olivia, ’63, MFSK, etc. RTTY starts at 14.080 up even above 14.100. 20 meters appears at present to be the best organized for the digital modes.
    17 meters: This is a growing band for the digital modes as 30 meters and hangs in around 18.100 or so. Listen.
    15 and 10 meters generally follows 20 relative to PSK and RTTY. 10 meters even with low sunspots now can be a surprise especially to the south.
  • Most folks pick a favorite mode and practice moving to other modes to find a favorite to add to the pie. I find Domino EX11 to be a great choice for me since it is very good in poor conditions although not that much activity. It’s a good mode for schedules.
  • Some modes you will chuck quickly. Olivia sounds great, but is wide and harder to tune… or it is for me.
  • Programs: Most are free like FLdigi. Most are still adding and improving but the updates are easy and neat. MixW is a favorite at $50 with free updates. Many have logs built in, some better than others.
  • Macros: This is an important feature for programs and again better with some than others. FLdigi macros are at the bottom of the screen which makes them easier for me. The more macros the better and FLdigi has four sets of 12 each.
  • The “F” keys corresponds to the line of macros for most programs. In other words you can hit the proper ‘F’ key and avoid the mouse if that is your thing.
  • IMD is a measure of how clean your signal will be. Many programs will allow the one you are talking to look at your signal and nearer to -28 or -30 (and higher) the better. One must not be keying in anything, but have the transmitter on for this to work. You can also give your buddy his ‘score’ as well if your program has this feature. Some programs are adding this feature as I type this.
  • The squelch is handy in most programs allowing you to adjust to stop the garbage. This is something which you can play with.
  • Be sure to play with the fonts and colors of various windows within your selected program. I change mine weekly to give me a new picture.
  • There is a learning curve for each program so don’t be discouraged. It’s fun and you will be surprised how it may click at 0300!
  • I have often said, perhaps too often that nothing helps a person do the digital modes like a buddy to listen and offer help. Please don’t forget this since it can truly help and keep down frustrations.
  • Again, the ARRL digital book for around $20 is worthwhile. Many of the other things I’ve read are assuming we are experts and just like to read. There are exceptions on the internet.
  • The digital modes are the most progressive, moving forward at a rapid rate, saving space on the bands, reducing the need for power, working much better for those challenged for antenna space, the elderly in assisted living, etc. I know of NO negatives for some digital modes in your repertoire of ham radio experiences.