Some digital modes on MF & LF

Using some of the digital modes on the lower Ham bands.


Get ready...

It's hard enough, at times, using SSB and CW modes on the HF ham bands, where most signals can be heard and communications with other stations from around the world can be done with moderately sized antennas and reasonable power levels. When operating in marginal conditions an alternative is available. The use of some clever software and interfacing with existing communications equipment, may allow the average user to continue to communicate with others around the world, even when the signals are inaudible. There is a plethora of software available and I choose only to name a few here, where communications on the newer MF and LF bands that have become available but, due to lack of antenna size for these bands (630m and 2200m) digital techniques are often employed to enhance communications with fellow hams.

CW decoding

Although CW is considered by some, not to be a digital mode, it can be generated and decoded by digital means. Most transceivers have this mode available to the operator and is usually decoded as an audible signal via the speaker or headphones. Likewise, the transmission is achieved via a morse key or paddle operated also by the operator.
Connect the audio output of the transceiver to the sound card input on a computer along with the sound output of the computer to the microphone input of the transceiver and we are almost there. To implement the push-to-talk, PTT, on the transceiver, we generally have an interface box of some description to allow the computer to control the transceiver via computer software control. There may be some buffering of signals and/or galvanic isolation included in this interface box, used to condition the signal to and fro', so the speaker and microphone/data leads may pass through this box also.
To decode Morse Code, any number of programs are available. Selection may be based upon ease of use, receive only or whether transmit may also be required. The text is normally entered via keyboard and commonly used text messages may be stored in an editable memory location that is usually accessed and recalled for transmission via a "soft key" as used in, say, contesting events.
Some programs I have used included the Terminal program, as part of both the Elecraft K3 and KX3 Utility software (free download). Probably not much chop if you don't have either of those radios!
FLDIGI - Fast and Light Digital Modem program. This free software allows both transmit and receive, has CW and other digital modes, provides capture, waterfall and text decode display. Quite amazing software.
Another program that may be a bit advanced for some, is DM780. Digital Master 780 also has CW and other digital modes along waterfall and text decode screen.
Argo is a QRSS/DFCW viewer. Slow more and other digital modes is supported, along with waterfall display, screen capture and file upload capabilities.
This is by no means any real list of any sorts, just a sample of a few I have come across and as with all software, hands on configuration is generally required.

WSPR - Weak Signal Propagation Reporting

Yes. 160m is in the MF band of frequencies. 3 to 30 MHz is classed as HF and 300 kHz to 3 Mhz is classed as MF. 30 Khz to 300 kHz is LF. As an aside, this is why 160m was not included the high power trials conducted in Australia as the trial was listed for the HF bands...! No one requested the 160m allocation in the MF band! Doh! Could this have been a Homer Simpson moment?
Back to WSPR. Well, it is a form of communications, of sorts. Yes, you do need the internet if you want to upload reports. You don't have to but it helps others if you can do this as it may means that conditions may be favourable for other modes of communication, yeah? This is exactly what does happen. Fellow hams send emails to individuals or groups and arrange "skeds" (scheduled contacts) at certain times usually pre-arranged and mutually convenient. We're all hoping for a successful contact. Especially if we are using any of these more "exotic" modes. Still a load of fun. So, WSPR does require critical timing, accuracy to within or less than one second. Apart from that, not a lot of power, it seems. Most stations are operating QRP levels and achieving amazing results. A good way to test propagation at different times and testing antenna efficiencies. It is good to see who else is on the band and where they are located.

WSPR on 160m #1

 15955km on 160m running only  10 watts as reported on website.

WSPR on 160m #2

 A world map helps gets the path  in perspective.

WSPR on 630m #1

 Made it over to New Zealand with  20 watts on 630m band.

WSPR on 630m #2

 Short lived top score. This what  spurs some of us on. Oh, well.  Good while it lasted!

WSPR on 630m #3

 Seen in five other states using 20  watt transmitter. Missed  Queensland and the A.C.T.

WSPR on 630m #4

 Using WSPR-X to capture other  stations and upload to the web.

WSPR on 630m #5

 A bit of activity on 630m! More  transmitters and receivers.

WSPR on 630m #6

 Screenshot of the Flex 1500 used  to monitor my Tx signal.

WSPR on 630m #7

 Snapshot of the waterfall display  of WSPR-X showing my transmit  signal.

WSPR on 630m #8

 WSPR-X decode screen showing  other hams using WSPR as  shown at my location.

WSPR on 630m #9

 Another snapshot of making it  across Australia.

WSPR on 630m #10

 And the published details on the  WSPRnet.org website.

WSPR on 2200m #1

 Showing that if you are there and  listening...

WSPR on 2200m #2

 783 kms with less than 20 watts!  I'm chuffed!

WSPR on 630m #11

 Some recorded distances on  630m by various hams in the  region.

Other modes...

Some other modes that seem popular at the moment are QRSS (plain on/off keyed slow morse), FSK/CW (frequency shift keyed slow CW), DFCW (dual frequency CW, dits and dahs on different frequencies), Slow-Hellschreiber (frequency shifted slow Hellschreiber), Hellschreiber, Domino and customable FSK patterns. WSQ2 is another specific program design by Con, ZL2AFP, for two way communication on both LF and MF bands. It allows two way chat with on screen text decode and waterfall. There are certainly a lot of clever people with clever skills.

Domino on 630m

 Nick, VK2DX, advertising a  weekend event on 630m band  using DominoEx4 protocol.

FSKCW & QRSS on 630m

 Here's some of us on the band  being capture by one of the  "grabbers".

QRSS decode

 Here is a good decode of  VK3TCT, John's signal using  ARGO software.

Ok. That's it for the moment. Hope to add some more detail as time permits...


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Steph - VK5FQ
Adelaide, South Australia,
AUSTRALIA