There are a significant number of programs available to the Amateur Radio operator enabling the use of digital modes. Some are self contained, others form part of a suite of programs designed for general logging etc (DM780, WinWarbler) . Choice will be made largely on the basis of cost or personal preference based on ease of use and available features. My own preference, having spent some time using all the programs discussed, is for DM780 which I judge to be state of the art. If computer screen space is limited or a simpler interface is required, next on my list are the more ‘compact’ programs of Fldigi and MixW.
MultiPSK offers more modes than any other but is definitely not for the beginner.
Software for Digital modes
A number of computer programs have been written for Amateur Radio Digital Mode operation. These operate in conjunction with conventional HF SSB radio transceivers, and usually use the PC sound card as the means of input and output to and from the radio. The sound card of a PC is a cheap effective analog to Digital converter. Some programs allow for the use of an external TNC or multifunction controller (ie Kantonics or SCS PTC) as an interface between radio and computer. Digital modes use audio-frequency signals which are modulated in various ways according to the mode. The computer and software link to the transceiver also by a serial port connection (CAT) which allows the program some control of the radio . Much of the software available is multi-mode, which means that they are able to operate many popular digital modes (ie DominoEX, MFSK16, PSK31, and RTTY) though not all are equal in this regard.
It can be difficult to identify some of the more obscure modes which appear on the amateur bands. Some digital software packages include the Reed Solomon ID protocol that sends a two second code before each text transmission informing the software at the other end what mode is being used to send the message and the center frequency for the transmission. At this time Fldigi, Digital Master 780 v5, and MultiPSK all implement this protocol.
Generally these programs have similar interfaces which include the following general features: A Receive Pane Text from decoded incoming signals is displayed here. When you transmit, the transmitted text is also displayed here, making a record of the QSO. A Transmit Pane Here is where you type what you want to transmit. Pressing a macro button will enter text into this pane. A Waterfall Pane This is the main tuning facility. The signals coming in can be seen, selected and tuned to. The type of signal being received can often be identified by its fingerprint on the waterfall. A Set of Macro Buttons These programmable buttons enable blocks of text to be entered into the transmit window. Text can include predefined fields (i.e. call-sign, name etc) Other controls and functions may also be offered.
How do we choose between the programs available for operating digital modes?
All programs perform operations under the surface that affect how signals are decoded etc. I don’t believe that there is much to choose between programs in this regard unless the operator is very technically minded and anxious to have control over all the parameters of the signal processing. Of more relevance, particularly to the novice user, is the programs user interface that determines just how easy the program is to use. The following issues are of relevance when choosing a program to use for digital modes. : -Does it have an attractive easy to use interface? -Are the controls intuitive? -Ease of signal identification and ease of selection. -Multiple signal decoding (like CW Skimmer). -Who is the caller? Have I worked them before? Have I worked this entity on this mode or band? Is this information readily available? -How easy is it to get the caller and QSO details into the log? -Integral QSO logging in a compatible format included? -What modes are handled by a program? -Easy switching between modes? -Ample macro buttons that are easily identifiable and grouped -How big a footprint does the program make on the screen? How much space does it take up in relation to what I have available?
The following programs have been reviewed below, and lower down the page are screenshots of many of the programs available.
Above ~ A typical 'Set Up' to work Digital Modes ___________________________
An Introduction to Digimodes
Receiving. Although it is possible to just wire the Transceiver headphone socket direct to the 'Line In' or 'Mic' sockets on a computer, and use one or more of the many programs avaiable free on the internet to just receive digital modes and produce text on your computer screen, it is much better to use some form of isolation between receiver and computer - this can range from simple opto-electrical coupling hardware costing about £30, to more sophisticated units. These 'cheaper' versions will be using your computers sound card, and 'tie up' use of that card. It is much better to obtain a Data Interface unit with a built-in dedicated Sound Card. There are several on the market, and available for around half the retail price on eBay or the other sites, where used Amateur Radio equipment is for sale.
Transmitting and Reception. There are many interfaces for use between the Transceiver and Computer, I believe the best solution is the Tigertronics 'SignaLink USB' interface, for many reasons - the main one being that it was easy and uncomplicated to install. The main feature of this interface is that it uses its own internal sound card, making the 'set up' very simple. It is around £90-100 to buy from the usual emporiums, Mine was £50 off Ebay 'As New'.
Digital Modes Described
(Ranked in order of common usage on HF).
1. PSK Most popular digital mode is the PSK31 variant. Lots of QSOs are to be had, with the favourite frequency being 14.070 USB.
PSK63, PSK125, PSK250 and PSK 500 are used much less frequently and signal "robustness" decreases as speed increases. PSK63
and PSK 125 are sometimes used in contests, much like RTTY. PSK31 and
other PSK modes suffer from the impact of loud signals nearby that can
cause the software to essentially only decode the strong nearby
station. Use of DSP, filters, and AGC settings can greatly reduce the
impact of this phenomenon, I usually work with AGC off..
As PSK 31 is the most popular Digital Mode on the Amateur Bands, It is given a more detailed description below.
PSK31 is a highly-efficient data mode that lets you work long distances, even when you can barely hear the signal. PSK31 stands for Phase Shift Keying 31 baud (or 31 bits per second/bps). Unlike RTTY (radio teletype) the characters are formed by changing the phase of the sound wave, not by using different tones. A PSK31 signal just sounds like a single tone or note with a slight wobble and is used for real-time keyboard-to-keyboard text “chats” over the air. PSK31 works very well with low power levels and for this reason it has become a firm favourite for QRP and stealth antenna operators.
PSK31 was developed by Peter Martinez (G3PLX) and introduced to the amateur radio community in late 1998. The mode was enthusiastically received and has since quickly spread into worldwide use.
PSK31 can often overcome interference and poor propagation conditions in situations where voice or other data methods of communication fail. Contacts can be conducted at less than 100Hz separation, so with disciplined operation at least 20 simultaneous PSK31 contacts can be carried out side-by-side in the bandwidth required for just one SSB voice contact. Typically, you can make good round-the-world PSK31 contacts with 10-25W.
Factoids :-Accuracy of decoded signals decrease as signals get weak. Affected by noise levels. Good for general "conversational" QSOs. Most non-English speakingstations use pre-set 'Macros' to communicate in English Text There are a few downsides to PSK31. One is that many contacts tend to be “rubber stamp” QSOs with amateurs just sending pre-prepared texts or macros. Some of these leave a lot to be desired as many operators seem to think that you are interested in what sound card and other computer equipment they are using. If you are a DX chaser the other limitation is that many DXpeditions don’t operate much PSK31 (if any) – you might be better off adding CW to your arsenal of skills, but if you are limited in terms of what antennas you can put up PSK31 will let you make guaranteed contacts when SSB could be virtually impossible. HF PSK31 Frequencies
There are many free programs available on the internet, some of the popular ones are Airlink Express, MultiPSK, FlDigi, Digipan, etc.A favourite for many is one that you have to buy, very easy to use and intuitive, called 'MixW2, - (See Screenshot, below).....
A Screen Shot of the program 'MixW' being used in PSK31 Mode
MultiPSK program in action (Above). This free program, plus the other one pictured above (MixW) can receive and decode a good number of the digital Modes, described later on this page. Most other programs are dedicated to just one mode.
'WinPSK' in action. This is perhaps one of the easiest PSK31 programs for a beginner to start with
A Screenshot of Digital Master 780, a program for PSK31 This Program is a part of the Ham Radio DeLuxe Suite, which includes Rig Control and Logging all interlinked. (With this program you can monitor up to 20 Stations at once!)
Screenshot of FLDigi in action,
This digital mode is getting more and more popular. Slow callsign and signal report digital mode, takes almost a minute to send a 13 letter message at the 60/0 second point of each minute. Essential to synchronise PCs using the mode all to the same second this is done with a program called 'Dimension 4' which synchronises every computer to the Atomic Clock. Extremely good with weak signals and low power. Lots of activity . great for long distance "hauls" to Asia and Oceania. Only very low power is needed to get a signal round the world. Great where it is impossible to erect bigger and more efficient antennas.
Screenshot of JT65HF Program in action
This shows me (2E0JJH then) 'working' a Japanese station JA1FMN on 14.076 Mhz ....You will see that he is calling CQ - I go back with 10 Watts, but he calls 'QRZ' - so I up the power to 20 Watts, and we exchange signal reports in -db, and then exchange 73's. This just shows what is possible, without anything more than a USB interface, and a free program. Frequencies used are 7.0760, 14.0760, 21.0760 and 28.0760 Mhz.
3. WSPR (PROUNOUNCED 'WHISPER)
Slow weak signal mode. Often one-way beacon only but some 2-way versions of the software still exist. Callsign , QTH, and signal report mode only. No QSO-type conversations. Fairly commonly heard on 30M. Usual Power on Transmit is 5 - 10 Watts
'Distant Whispers' One of the things that makes communicating with amateur radio more fun than using the Internet or the phone is that you never know where your signals will be received. Short wave radio propagation is never completely predictable, and can often surprise you. If this is an aspect of radio that fascinates you, then you'll enjoy using WSPR. WSPR is a piece of software that enables you to participate in a world-wide network of low power propagation beacons. It enables your radio transceiver to transmit beacon signals, and to receive beacon signals from similarly-equipped stations in the same amateur band. Because participating stations usually upload spots that they receive in real time to a web server, you can find out within seconds of the end of each transmission exactly where and how strongly it was received, and even view the propagation paths on a map.
If you left WSPR running while you were doing something else, you can also search the database to find out later where your signals were received during the day. You can analyze past signal reports to see the effect of seasonal propagation changes or antenna improvements.
SCREEN PICTURE OF WSPR RUNNING ON 10 MHZ Time, Signal Strength, Frequency, Callsign and Maidenhead Square are shown.
PSK REPORTER Some Digital Mode Programs can be configured to interact with this Mapping Program. I am using it to report on Stations receiving my signals from my WSPR program running at just 10 Watts !!! Below is a 'Map Report' from WSPR on 13 August 2012 on 20 Metres for 3 hours. WSPR stands for Weak Signal Propagation Reporter, but it's pronounced "Whisper" - an appropriate name as it is all about sending and receiving signals that are barely audible.
WSPR is a software application written by Joe Taylor, K1JT, a Nobel Prize-winning Princeton physicist. It was first released in April 2008. It uses a transmission mode called MEPT-JT. The "JT" stands for Joe Taylor, while MEPT stands for Manned Experimental Propagation Transmitter.
MEPT is not something specific to WSPR. MEPTs are very often simple home-built QRP transmitters that send beacon messages using very low-speed Morse (QRSS). Their very weak signals are copied visually using software called a "grabber" - a horizontal waterfall display capable of detecting and highlighting signals well below the noise threshold. The content of a transmission is determined - as with many other weak-signal QRSS modes such as EME (moonbounce) - by literally reading the dots and dashes as they are displayed on the waterfall.
The "manned" aspect of MEPT simply relates to the operator's licence conditions. It is not necessary to obtain a special dispensation to operate a MEPT station because you are present while it is in use, just as you would be when using CW, SSB or another data mode. In fact, some MEPT enthusiasts discourage the use of the term "beacon" because beacon operation without a special permit is prohibited by some licencing authorities.
Once set up, operation of WSPR is completely automated. The software logs every transmission you make, as well as all the "spots" (decoded MEPT-JT signals) received. So this is something you can do when you are otherwise engaged and not able to get on the air and make normal QSOs. Just how "hands-on" you need to be when operating WSPR is a matter between you, your licence authority and your conscience, but some people leave their WSPR beacons running 24/7 and some of that time, they must be asleep.
A CLOSER LOOK AT THE 'REPORT MAPS' ABOVE. When there are many stations in the map, you can zoom in to separate them
The three farthest stations . DU1SGA - Manilla, Phillipenes - 6682 Miles away WA2YUN - Wake Island, Hawaii - 7399 Miles away DP0GVN - Atka Bay, Antarctica - 8549 Miles away. A confirmation Card of the contact was received electronically (Below)
A Screenshot of 'Dimension 4' The most popular program for maintaining computers worldwide to an accuracy of less than one 100th of a second - essential for using JT65HF and WSPR as they have to 'Sync' with other Transceivers throughout the world
Still quite common on HF for APRS activity and bulletin-board email exchanges. Some Emcomm use. Slow and only fair when weak signals or QRM.
6. Pactor Very common , part of world-wide network of stations that send and forward email(WL2K) Very good weak signal performance and speed. Some keyboard QSOs to be had, but very rare. Peer to Peer exchanges possible when used in WL2K but mostly client to server activity.
7. Opera Like JT65A and ROS, generally a SLOW digital mode used for super weak signal detection. Callsign and signal reports. No conversations beyond that.
8. ROS Like JT65A and OPERA , generally a SLOW to medium speed digital mode used for super weak signal detection. Callsign and signal reports. Some conversational QSOs. Not legal on HF in USA since some feel it uses a prohibited Spread Spectrum technique.
9. Winmor Common , part of a world-wide network of stations that send and forward email (WL2K) Fair to good weak signal performance and moderate speed. Some keyboard QSOs to be had but very rare. Peer to Peer exchanges possible when used in WL2K but mostly client to server activity.. Also has a similar "cousin" mode , V4 Chat.
10.RTTY (Radio Teletype Telephony)
Used by DXpeditions , so good for chasing DXCC totals. LOTS of RTTY contests on weekends. Fair performance when faced with weak signals, QRM, QRN. Conversational QSOs and quick contest-type exchanges are common. AFSK RTTY is used with soundcards. FSK RTTY is produced by most modern rigs and the filtering usually ensures better performance than AFSK RTTY.
Screenshot of 'MMTY' A program used for transmission and reception of RTTY Signals
5. SSTV Poor when faced with weak signals or QRM. There are several modes - usually Auto-detected in the program. Quite common on HF usually 20M (14.230Mhz) and 40M. Digital SSTV programs like those within 'Easypal' or 'Multipsk' can perform perform better in weak signal conditions. Exchanges of "pictures" like QSL cards and, annoyingly, bikini clad women.
Digital Master 780 Program for SSTV (Exchanging Pictures with an American Radio Station)
6. Olivia Quite common, especially in digital nets. Olivia 8/500 seems like the most common variant but some 8/100 and 32/1000. Used frequently for digital messages transfers on HF and VHF point-to-point Emcomm work. Some conversational QSOs to be had but you can go several hours without hearing any signals.
7. MT63 Moderate throughput under weak conditions but suffers badly when faced with QRN. Copes with QSB quite well. Most common variant on HF is MT63 1000 but some MT63 500 is used. On VHF and UHF MT63 2000 is very effective. Used a lot by Emcomm groups on HF, exchanging bulletins, ICS forms, and much more. Rare to hear QSOs using this mode.
8. FSK441 Used mostly for meteor scatter on 6M, 2M and 70cm. Very efficient for detecting very quick signal bursts, good weak signal performance. Used only to exchange signal report, QTH. and callsign. Only in WSJT software
9. HELL Moderate performance in terms of weak signal work. Requires good eyesight. Some conversational QSOs to be had but you can go several hours without hearing any signals.
10. MFSK Moderate to good performance in terms of weak signal work. Some conversational QSOs to be had but you can go several hours without hearing any signals.. Used with PSKmail as MFSK32 or MFSK 64 but MFSK16 is most common if used for general QSOs.
11. ALE 141 Used by 100-200 stations regularly and they put out periodic "soundings" that can be heard throughout the day. Sophisticated communications system used by Govt agencies and the military but not widely adopted by hams (alas). Several messaging sub-systems with good through-put including ARQ methods. Limited by some OFCOM & FCC restrictions of speed and bandwidth. Only available in PC-ALE and Multipsk software and via firmware in some high-end commercial radios.
12. Thor Moderate to good performance in terms of weak signal work. Some conversational QSOs to be had but you can go several hours without hearing any signals.. Used with PSKmail as THOR 22 is most common . May sometimes be used by Eccomm nets to pass point-point traffic. Not in all common software applications.
13. Lentus Super slow callsign and signal report digital mode. Extremely good with weak signals and low power. Moderate activity. Only available via Multipsk software
14. Contestia Similar to Olivia in terms of performance but not very common. Can go days without hearing signals.
15. Throb Fair to moderate performance in terms of robustness. Can be used as conversational mode. Can go days without hearing a signal.
16. DominoEx Similar to Olivia in terms of performance but not very common. Can go days without hearing signals except when used by PSKMAIL stations and some NBEMS emcomm stations.
17. PAX Good weak signal performance but only available in Multipsk. Can go days without hearing signal. 18. ALE 400 Good weak signal performance but only available in Multipsk. Great ARQ performance with auto-resync. Can go days without hearing a signal. Can be used for conversation QSOs and can be configured to send email and files.
19. JT6M Used mostly for meteor scatter on 6M, 2M and 70cm. Very efficient for detecting very quick signal bursts, good weak signal performance. Used only to exchange signal report, QTH and callsign. Only in WSJT software
20. Jason Another super but slow mode. Very good under weak signal conditions.
How to identify the modes. There are three things you can do to easily narrow down the list of possible modes and quickly identify them.
1. What frequency is it on? If it is on 7035, 10.100, 14070, 18.100, 21.070, 24.920, 28120, or within 2 Khz of those frequencies, it is almost certainly PSK31 or PSK63. If it is on 7076, 14076, 21076, 28076, it is almost certainly JT65A. PSK31 and JT65A will be at least 75% of what you will hear on the entire HF band, so by learning their frequencies quickly you will be able to discern 75% of all signals.
2. By Sight. Observing the width of a digital signal will also enable you to quickly narrow in on the possible signals. PSk31 should be around 31 Hz wide in your waterfall. To some its like a 31 hz wide single vertical trace, it may look like two traces, or tram lines, 31 Hz apart. RTTY (in ham bands) is 170 Hz wide and be seen more clearly as two vertical traces on your waterfall. On a busy weekend, if you can easily tell a PSK31 signal and a RTTY signal , you will recognize 85% of the signals on the band. If you know that RTTY is very rarely within 2-3 Khz of 14070, 21070, 28120,, you will have extra info to make your decision (RTTY typically shows up above 14080, 21080 , and 28080 for a 10 to 15 Khz swath during a busy contest). You can also begin to recognize the narrow "zig-zag" of a WSPR signal or the almost domino dots-like pattern of a strong JT65A signal. A little practice and you will get most of the common modes instantly recognizable. YouTube has many examples of these modes that you can view.
3. Hearing. Your ears can be quite valuable in this regard. The sounds are not easy to describe in writing BUT if you have the software installed, all you need to do is press TRANSMIT (with a dummy load or no radio connected) and you can easily hear what the modes sound like. Some have a different sound if they are just idling, so activate each mode and execute a macro with a CQ in it. Eventually you will easily recognize Hell (a sick CW-like sound), the shrill RTTY sound, or the low roaring noise of MT63 signal. Some modes like Olivia , Contestia, Thor, MFSK16, and Domino sound quite alike. Those you really have to practice. These mode have so many variations of settings that only sound SLIGHTLY different , so it gets hard for people who do NOT use RSID.
RSID. An interesting and useful program used to identify digital modes, but is dependent on people using it, it also does not ID every common mode. Often RSID is required to identify modes, but your ears can tell Olivia from MFSK16 and Thor from Olivia... with practice. Remember that if you take the frequency on the band and the width of the signal in the water fall , in to account... you should narrow it down to just 2-3 modes. If you are in a section of the band where Olivia , Contestia, Thor, MFSK, and Domino is being considered... remember thant Olivia is the most common of these modes followed by MFSK, So give those two a try first.
If you are on frequencies commonly used by PSKMAIL servers (e.g. 10147) PSK250, PSk500, THOR 22 and MFSK32 are the modes to try. PACTOR and WINMOR signals are present throughout every band, carrying email and file traffic. You will likely not care about these signals unless you have traffic to pass , you can't eavesdrop on message content. So learn how these signals sound and appear, that way you will not waste time thinking it is an exciting QSO mode. Some modes like JT65A give another clue.... they ALWAYS start a transmission at the top of the minute (give or take 1-2 seconds) and end after 48 seconds. WSPR does essentially the same but transmits for about 2 minutes. Opera has differing lengths, like LENTUS , they can last up to 10 minutes!
Please click the button below to return to the Navigation Menu