AmateurRadio.com

This article is part one in a multi-part series.  Part 2 is located here: One Aspect of Amateur Radio: Good Will Ambassadors to the World.  Part 3 is located here: In Response — Can’t We All Just Get Along?

We’ve all heard it at least once:  no one owns a frequency.

By law, amateurs must keep the transmissions from their station within the bounds of the allocations granted to license-holding operators–within these bands that are allocated for amateur radio use.  Amateurs are expected to follow band-plans, which guide us to which mode can be used in a band.

Subbands — Band Plans

There are many decades of constant refining of the standard operating procedures–perhaps we can call them, traditions–that, for the most part, work out pretty well for most amateur radio operations on our precious allocations in the radio spectrum.  Each band–a slice of radio spectrum between a lower frequency and a higher frequency–is made up of subbands.  These subbands are slices within a specific band (allocation), in which amateurs participate in two-way communications by using a particular mode of transmission, like single side band or CW.

For instance, Morse code enthusiasts use CW (continuous-wave modulation, i.e., A1A) between 14.000 MHz and 14.150, which is the subband that exists in the larger allocations known as the 20-Meter Band.  The 20-Meter Band is 14.000 MHz to 14.350 MHz, and the regulating bodies (such as the FCC in the USA) have directed through law that voice modes cannot be used between those subband frequencies from 14.00 MHz to 14.15 MHz. Voice modes can be used from 14.15 MHz up to 14.35 MHz, with certain license class variations. Read the PDF from the FCC: FCC ONLINE TABLE OF FREQUENCY ALLOCATIONS

CW is not the only mode allowed in the 14.00-MHz-to-14.15-MHz subband.  The regulations stipulate that a number of data modes can be used in this subband. There are specific requirements that a mode must meet, in order to comply with regulations–these are known as the authorized emission types.

Gentlemen’s Agreements

Amateur radio operators, decades ago, began discussing, then agreeing to, agreements between all operators as to where specific modes can be used, so those operating the different modes do not trample on each other’s transmissions.  These agreements are known as our band-plan gentlemen’s agreements.  They exist to help minimize interference–QRM–and to help foster good operating procedures between the different groups.

The band plans that have evolved through the decades are not regulations, and do not mean that any particular group of amateur radio operators own any frequency or subband.  A mode does not own a particular subband.  Amateur radio operators are not encouraged to start transmitting a mode that is typically found in that subband, if someone else is on that frequency using a mode not expected.

Just because some other operator is using the subband for a mode not in compliance with the gentlemen’s agreement, don’t purposefully try to eject that operator.  At the same time, the gentlemen’s agreements exist to help amateurs avoid interference with others that are using different modes.  Thus, the operator who has chosen to use a non-standard mode for a subband known to be used for some other mode should move that operation to the subband identified to be for that operator’s current mode of transmitter emissions.  In other words, do not QRM another amateur radio operator, and do not cause confusion and frustration by barging into a subband for a mode that you are not intending to use.  Use the mode expected in the subband of your current operations.

This concept is especially helpful when we consider weak-signal operations.  If a very strong, loud teletype transmission begins in a subband that is set aside for weak-signal propagation modes like WSPR, then it defeats the efforts of the operators making the attempt to have successful weak-signal two-way communications.  Thus, the teletype transmission should be made in a subband where teletype operation is expected and acceptable.  And, WSPR should stay in the subband where people expect to find WSPR signals.

This concept is also applied to VHF or higher bands.  Why?  If repeaters are parked on known repeater subbands, then weak-signal single-sideband communications can take place in a subband where repeaters are not allowed.  By allowed, though, I mean, by agreement with gentlemen’s agreements.  Regulators have stayed out of the amateur radio operations except by creating regulations at a high-level–for instance, the FCC stipulating that voice communications are not allowed between 14.000 MHz and 14.150 MHz, in the 20-Meter band.

The Frequency Grabs by the WSJT Developers, Planners, and Leadership

With several current release candidates of the WSJT-X software by Joe Taylor, the group of developers and leadership have programmed into the WSJT-X software a set of NEW default frequencies.  These new frequencies are in addition to their current pre-programmed frequencies that the amateur community now identifies as, The FT8 Subbands.

The new proposed frequencies are right on top of other subbands where other modes have been operating for decades (such as PSK and Olivia, and many others).  There was no community discussion, except within the WSJT community.  And, when someone protested the take-over of other well-established subbands, those protests were shot down.  The stated reasons included, “Well, those other modes are not very active or popular, because spots are not showing up on various spotting networks.”  Such reasons break down on deeper consideration–for instance, most spotting networks are not programmed to automatically identify Olivia transmissions.  CW, PSK, and FT8 are programmed into scanners, but other modes are ignored.

This behavior, considered rude, arrogant, presumptuous, and anti-gentlemanly (referring to well-established gentlemen’s agreements) has happened before, with the initial release of FT8.  They (the WSJT-X developers and leadership) simply picked a frequency slice of each subband, without true collaboration with the wider amateur radio community.

When this columnist and fellow amateur radio community member, attempted a discussion, the retort from an official representative was an absolute dismissal of any protest against the choice and method of frequency options within the WSJT software. While the software marks these frequency as suggestions, only, these defaults are used without question by the operators of said software.  And, the mode is so fast that there’s no human way of truly monitoring the frequency before use, to see if some other mode is in operation.  Besides, weak-signals that are present but cannot be heard by one’s ear, might well be in operation.  Subbands exist to keep QRM from covering up the weak signals of the mode expected at that frequency.

Enter the IARU…

The IARU has decided to step in and join the discussion.  “The International Amateur Radio Union has been the worldwide voice of radio amateurs, securing and safeguarding the amateur radio spectrum since 1925.”  The IARU guides regulating bodies like the FCC, regarding the administration and rule-making pertaining to amateur radio.

The IARU states, on their website,

The radio spectrum is a priceless natural resource. Because radio waves do not respect borders, the use of the spectrum must be regulated internationally. This is accomplished through the International Telecommunication Union (ITU), a specialized agency of the United Nations. Through World Radiocommunication Conferences (WRCs) held approximately every four years the ITU revises the international Radio Regulations which have the force and effect of a treaty. The Radio Regulations allocate the spectrum to different radiocommunication services such as broadcasting, mobile, radar, and radionavigation (GPS). The most recent WRC was held in October-November 2019. The next one is not yet scheduled but is expected to be held in 2023, so it is usually referred to as WRC-23.

New uses of the spectrum are being developed every day. This puts enormous pressure on incumbent users who are called upon to share their spectrum access with new arrivals. The allocation process is extremely complex, especially when satellite services are involved.

Reportedly, from first-hand communication from one IARU representative,

WSJT-X RC3 has 14074 kHz again for FT8. IARU is intervening. Stay tuned. I am asking for further suggestions.

73 Tom DF5JL
IARU R1 HF Manager

This is very welcomed news!

What ought to take place, as quickly as possible, is to rally the different interested parties, like the Olivia group, the PSK groups, the various CW groups like CWOps, FISTS, and the SKCC, and many others, for ideas and suggestions.  A discussion must take place in the hope that new gentlemen’s agreements can be made, that include the FT8 and FT4 operations, without stepping on the subbands of other digital modes.

As Tom says, STAY TUNED.

If you have suggestions, please comment. This columnist will summarize the main ideas of the comments and forward them to Tom.  You may also contact the IARU managers and let them know your suggestions.

Discussions in the Olivia community are ongoing, too.  Join in at OliviaDigitalMode.net even if you are not yet an Olivia operator.

On Facebook, you may also discuss your thoughts, in either the Olivia Digital Modes on HF group or in the Digital Modes on HF group.

If you use FT8 and FT4, voice your concerns and ideas, too.  Open dialog, without declaring war, is welcomed and hopefully will prove productive.

This article is the first in a series focusing on band plans, and gentlemen’s agreements. Please stay tuned for more installments.

Tomas Hood, NW7US, is a regular contributor to AmateurRadio.com and writes from Nebraska, USA. Tomas is the Space Weather and Radio Propagation Contributing Editor to ‘CQ Amateur Radio Magazine’, and ‘The Spectrum Monitor’ magazine.

About a month ago, I asked,

“What is going on with you during this challenging situation?” and, “How do you use amateur radio, now that we are all stuck at home?  Are you using ham radio more, now?  Less?“

I am moved to say, “Thank you, to each of you who commented and even those who made a video response. I sure appreciate it!“

During that video blog (or, Vlog), back a month ago (link: Chat From a Quarantined Software Engineer – Welfare Check!), I mentioned my need for dental surgery. 

I did have to have the tooth removed.  It was completely split down the middle (top to bottom), down to the root.  There was no justifiable way to save the tooth. 

I now am missing two bottom back-most teeth, and one bottom, back-most tooth.  I can report that I have healed up nicely.  I am starting to enjoy a hamburger or two.

Through all of this, I’ve still been working. Also, I’ve been involved with a LOT more ham radio–especially with Morse code activities.

How has the last month treated you?  After watching this new video (below), please leave a comment or two, or three; let hear from you, okay?

More than anything, please leave a comment to let me know how you are doing.  I hope to hear from you.

Here’s the video:

[embedyt]https://www.youtube.com/watch?v=vFGbw7d91GA[/embedyt]

73 de NW7US dit dit

This is a welfare check on you. Please leave a comment on how you are faring, what is happening in your situation with the lock-down.

Are you quarantined? Working from home? Did you lose your job? How are you doing during this crazy time?

What is going on with you during this challenging situation?

I talk about what I’m doing, too.  I’m quarantined at home.  I can work from home, as I am a senior software engineer.  I can do my job by remote access to a virtual workstation, through a secure VPN connection.  I’m blessed that I still can work during this lock-down.

But, I have a medical emergency – a dental problem – and trying to be seen by a dentist is difficult, because all of the local dentists were told to shut down their daily business and quarantine.  Only emergency appointments are being made!  I was finally, after two days of phone calls, able to schedule an emergency visit to my dentist!

I want to know: How do you use amateur radio, now that we are all stuck at home?  Are you using ham radio more, now?  Less?

Please leave a comment to let me know how you are doing, and answer the other questions, too.  I hope to hear from you.

I hope to meet you on the shortwave amateur radio bands.  I am usually using Olivia, or Morse code CW.  More information about Olivia: http://OliviaDigitalMode.net.

Be healthy, be safe, stay sane!

This past weekend (third full weekend in February, February 15-16, 2020) is the ARRL International CW Contest (ARRL DX CW link: http://www.arrl.org/arrl-dx ). This is interesting to my study of radio signal propagation as a columnist and as an amateur radio operator​ because of the contest objective: “To encourage W/VE stations to expand knowledge of DX propagation on the HF and MF bands…” This contest is a good way to get a feel for current propagation–though there are caveats.

Speaking of Morse code and the CW mode on our amateur bands: those of you using CW during contests, do you send by hand or by computer?  Do you copy the code by head, or do you use a computer for decoding?

Just curious about those of you who use CW. Do you send by hand or computer? Receive by head or computer?

In most contests like the ARRL DX CW contest, I copy by ear, and send mostly by rig keyer. If needed, I use a single paddle key with the Icom rig’s internal keyer to answer unique questions and so on.

Below is a quick demo of using the internal Morse code keyer in my Icom IC-7610 transceiver.

V47T, in the Saint Kitts and Nevis Island in the Caribbean, is calling CQ TEST in the ARRL DX CW contest.

Using the programmable virtual buttons, in which I programmed my callsign, NW7US, and other info, I answer and make a complete contest QSO.

In activity like the Straight Key Century Club (SKCC – https://SKCCGroup.com) K3Y special event, it is all manual. I send my Morse code using a WWII Navy Flameproof Signal Key, and decode with my ears.  It is contextual for me.

[embedyt] https://www.youtube.com/watch?v=vm8UJst6umA[/embedyt]

How do you do contesting Morse code?  Bonus question: How do you do logging while doing contest operation?

73 es best dx = de NW7US dit dit

Meme: Car and Woman Arguing, 73

“Best regardses” and “Best regards’s”

That’s silly, of course. We who speak and write in the English language know that you should not pluralize a word that is already in its plural form. “Best regards” means, “I wish you the best of regards.” It is implied that there is more than one regard. Perhaps there are a few, perhaps many more. It then is clear that we wouldn’t normally pluralize “regards,” into, “regardses.”

It is also silly to say that the best of regards owns something.  How can a regard let alone a group of regards own anything?  So, why “73’s” when written?

Old SWLer QSL Card With 73’s

The usage of “73” comes from early landline telegraph (typically railroad telegraphy landlines). Originally devised in the era of telegraphs, 73 and other numbers were used to speed up the transmission of common messages over landlines by mapping common messages to these specific numbers.  And, numbers were quicker to send than the longer messages the numbers replaced.

QST, April 1935, on page 60, contains a short article on the origin of the amateur radio vernacular, 73. This article was a summation of another article that appeared in the “December Bulletin from the Navy Department Office of the Chief of Naval Operations,” published December of 1934.

A skilled landline Morse code operator, in action.

Here’s a quotation from that Navy article:

“It appears from a research of telegraph histories that in 1859 the [land-line] telegraph people held a convention, and one of its features was a discussion as to the saving of ‘line time.’

A committee was appointed to devise a code to reduce standard expressions to symbols or figures. This committee worked out a figure code, from figure 1 to 92.

Most of these figure symbols became obsolescent, but a few remain to this date, such as 4, which means “Where shall I go ahead?’. Figure 9 means ‘wire,’ the wire chief being on the wire and that everyone should close their keys. Symbol 13 means ‘I don’t understand’; 22 is ‘love and a kiss’; 30 means ‘good night’ or ‘the end.’

The symbol most often used now is 73, which means ‘my compliments’ and 92 is for the word ‘deliver.’ The other figures in between the forgoing have fallen into almost complete disuse.”

We can see, then, that “73” mapped to “best regards” or “my compliments” and was intended as a general valediction for transmitted messages.  That’s why it is silly to say, “73s,” as that maps to, “best regardses” – 73s adds the plural to a plural.  (And, don’t make it possessive, as in using, “73’s” – a regard cannot own something).

Cartoon: Jeeves, there is no plural for 73…

For reference and some more interesting background on this, see http://www.signalharbor.com/73.html

An example of on-the-air conversation (or, QSO—“QSO” is the shorthand Q-code for, “two-way exchange of communications”) illustrates proper usage of 73. When saying your goodbye, you would tap out the Morse code as follows:

TNX FER FB QSO. C U AGN. 73 ES HPY NEW YR.

That is interpreted as, “Thanks for the fine-business chat. I hope to see you again for another chat. Best regards and happy new year.”

This, if you choose to throw around shorthand Morse code number codes when you are speaking, you wouldn’t say, “73s.” You would say, “73.”

The Old Man Hiram Percy Maxim 1AW used 73’s on his QSL cards.

My friend, David Edenfield, opined, “This idea is beyond turning into glue from the dead horse it’s beating again. This is so petty to be concerned with this. Even the Old Man Hiram Percy Maxim 1AW used 73s on his QSL cards.”

Well, even Hiram Percy Maxim has been incorrect and incorrectly used grammar. (chuckle)

There is something to be said about teaching new amateur radio operators the best of our traditions, history, skills, procedures, protocols, ethics, and culture. There’s no rational argument that can make a case that allowing these aspects of our service and hobby to degrade over time (by the lack of Elmering) is a good way to see our service and hobby thrive and progress.

I don’t see any slippage from high standards as being a good strategy for nurturing growth, progress, and effectiveness of our service and hobby. Keeping some level of excellence in every aspect of our hobby can only be beneficial.

In this case, how many new hams that learn to repeat ham lingo know anything of the history behind the common “73?” My dead horse turned glue is educational and it is my belief that educating about origins elevates the current.

73 – NW7US

NW7US QSL Card (circa 2019)

..

Man, lots and lots of Morse code on the ham bands, this weekend. The CQ Worldwide CW Contest weekend was hopping with signals!

How did you do this weekend? How were conditions on the various contest bands?

Comment here and your report may make it into the propagation column in an upcoming edition of the Radio Propagation column in CQ Amateur Radio Magazine.

Here are a few moments as heard at the station of the CQ Amateur Radio Magazine propagation columnist, in Lincoln, Nebraska (yeah, that’s me, NW7US).

[embedyt]https://www.youtube.com/watch?v=eWCbtIOJmLI[/embedyt]

Here are the results of my dabbling with the Icom rig and this contest:

 NW7US's Contest Summary Report for CQ-WW
 Created by N3FJP's CQ WW DX Contest Log
 Version 5.7  www.n3fjp.com

 Total Contacts = 55
 Total Points = 8,979

 Operating Period: 2019/11/24 10:23 - 2019/11/24 22:51

 Total op time (breaks > 30 min deducted): 3:58:46
 Total op time (breaks > 60 min deducted): 4:45:17

 Avg Qs/Hr (breaks > 30 min deducted): 13.8


 Total Contacts by Band and Mode:

 Band       CW   Phone     Dig   Total       %
 ----       --   -----     ---   -----     ---
   80        8       0       0       8      15
   40        7       0       0       7      13
   20       25       0       0      25      45
   15       15       0       0      15      27
            --   -----     ---   -----     ---
 Total      55       0       0      55     100

 Total Contacts by State \ Prov:

 State       Total     %
 -----       -----   ---
                52    95
 HI              3     5

 Total = 1


 Total Contacts by Country:

 Country                      Total     %
 -------                      -----   ---
 Canada                           6    11
 Brazil                           5     9
 USA                              5     9
 Argentina                        3     5
 Costa Rica                       3     5
 Hawaii                           3     5
 Bonaire                          2     4
 Cayman Is.                       2     4
 Chile                            2     4
 Cuba                             2     4
 Japan                            2     4
 Mexico                           2     4
 Aruba                            1     2
 Bahamas                          1     2
 Barbados                         1     2
 Belize                           1     2
 Curacao                          1     2
 Dominican Republic               1     2
 French Guiana                    1     2
 Haiti                            1     2
 Honduras                         1     2
 Martinique                       1     2
 Montserrat                       1     2
 Nicaragua                        1     2
 Senegal                          1     2
 St. Kitts & Nevis                1     2
 St. Lucia                        1     2
 Suriname                         1     2
 US Virgin Is.                    1     2
 Venezuela                        1     2

 Total = 30


 Total DX Miles (QSOs in USA not counted) = 151,407
 Average miles per DX QSO = 3,028


 Average bearing to the entities worked in each continent.
 QSOs in USA not counted.

 AF =  83
 AS = 318
 NA = 124
 OC = 268
 SA = 137


 Total Contacts by Continent:

 Continent   Total     %
 ---------   -----   ---
 NA             32    58
 SA             17    31
 OC              3     5
 AS              2     4
 AF              1     2

 Total = 5


 Total Contacts by CQ Zone:

 CQ Zone   Total     %
 -------   -----   ---
 08           13    24
 03            7    13
 09            7    13
 07            6    11
 11            5     9
 13            3     5
 31            3     5
 04            2     4
 05            2     4
 06            2     4
 12            2     4
 25            2     4
 35            1     2

 Total = 13

Wow. What a radio!

One of the most useful (and, to me, amazing) features of this Icom IC-7610, is the IP+ function, which, when turned on, improves the Intermodulation Distortion (IMD) quality by optimizing the direct sampling system performance. This function optimizes the Analog/Digital Converter(ADC) against distortion when you receive a strong input signal. It also improves the Third-order Intercept Point (IP3) while minimizing the reduction of the receiver sensitivity.

In short: I was listening to an s-0 (i.e., no strength-meter movement) weak signal of a DX station, when right adjacent to the frequency came an s-7 signal, wiping out my ability to copy that weak signal. I turned on the IP+ and the distortion of the adjacent signal disappeared, and once again, I heard the weak signal IN THE CLEAR! WOW!

This video is a quick capture of my running the Olivia Digital Mode on HF, on the 30-Meter band. The transmissions are of a two-way Olivia digital-mode radio conversation between station K8CJM and station NW7US on 12 November 2019 (UTC date). K8CJM is located in Dayton, Ohio, and I am located in Lincoln, Nebraska. I’m running the radio at full power. The radio is rated as being able to handle 100% duty cycle at full power. The radio ran cool, no significant heating.

A few months ago, a lightning strike took out my ham radio station. The antenna was NOT connected, but I did not unplug the power supply chain and my computer from the wall. The surge came in through the power mains, and fried my uninterruptable power supply, the interfaces between my PC and radio, and fried the radio. Thankfully, all of that was covered by my homeowner’s insurance policy, less the steep deductible. My insurance covered all of the blown items, and that provided me this chance to obtain a repack version of the Icom IC-7610. I bought an extended four-year warranty.

CAUTION: Check the documentation of your transceiver/transmitter. NEVER run your radio’s power out at a level that exceeds what it can handle in reference to the duty cycle of the mode you are using. Olivia, for instance, is a 100-percent duty cycle mode. Morse code is NOT quite 100% duty cycle. Nor is SSB, a mode that operates with a duty cycle much lower than 100%. Your radio’s manual should tell you the specifications regarding the duty cycle it can handle! If you run more power than your radio can handle with the given duty cycle of the mode in use, you will blow your radio’s finals or in some other way damage the radio! Beware! I’ve warned you!

Compression and ALC!?

Some have noted that it appears that I’ve left on the Compression of the transmitted audio. However, the truth is that compression was not being used (as is proof by carefully taking note of the zero meter movement of the Compression activity). I had the radio set for 20-Meter USB operation on the Sub VFO. Compression was set for standard USB operation. Note also that the radio was transmitting USB-D1, which means the first data/soundcard input to the radio.

Also, some people complain about my use of ALC, because, in their view, ALC (automatic level control) is a no-no for data modes.

The notion that one must NEVER use ALC when transmitting digital modes is not accurate.

Multi-frequency shift keyed (MFSK) modes with low symbol rate–such as the Olivia digital modes–use a single carrier of constant amplitude, which is stepped (between 4, 8, 16 or 32 tone frequencies respectively) in a constant phase manner. As a result, no unwanted sidebands are generated, and no special amplifier (including a transmitter’s final stage) linearity requirements are necessary.

Whether the use of ALC matters or not depends on the transmitted digital mode.

For example, FSK (Frequency-Shift Keying; i.e., RTTY) is a constant-amplitude mode (frequency shift only). In such a case, the use of ALC will NOT distort the signal waveform.

PSK31 does contain amplitude shifts, as an example, therefore you don’t want any ALC action that could result in distortion of the amplitude changes in the waveform.

On the other hand, the WSJT manual says that its output is a constant-amplitude signal, meaning that good linearity is not necessary. In that case, the use of ALC will NOT distort the transmitted signal-amplitude waveform. You can use ALC or not, as you choose when you run WSJT modes, or Olivia (MFSK).

Clarification

Nowhere in this am I advocating running your audio really high, thinking that the ALC will take care of it. I am not saying that. I am saying that some ALC is not going to be an issue. You MUST not overdrive any part of the audio chain going into the transmitter!

Transmit audio out of the sound card remains at a constant amplitude, so there will be no significant change in power output if you adjust your input into the radio so that the ALC just stops moving the meter, or, you can have some ALC meter movement. You can adjust your audio to the transmitter either way.

If the transmitter filters have a significant degree of ripple in the passband then you may find that RF power output changes with the selected frequency in the waterfall when there is no ALC action. Allowing some ALC action can permit the ALC to act as an automatic gain adjustment to keep the output power level as you change frequencies.

Linear and Non-Linear

Regarding linear and non-linear operation (amplifiers, final stages): While a Class-C amplifier circuit has far higher efficiency than a linear circuit, a Class-C amplifier is not linear and is only suitable for the amplification of constant-envelope signals. Such signals include FM, FSK, MFSK, and CW (Morse code).

If Joe Taylor’s various modes (in WSJT software) are constant-envelope signals, than class-C works, right? At least, in theory.

Some Additional Cool History

The digital mode, Thor, came out of DominoEX when FEC was added. Here is an interesting history of FSQ that seems to confirm that FSQ is like MFSK, so no problem with a bit of ALC.

The following is from https://www.qsl.net/zl1bpu/MFSK/FSQweb.htm

History – Let’s review the general history of Amateur MFSK modes. The first Amateur MFSK mode developed anywhere was MFSK16, specified by Murray Greenman ZL1BPU, then first developed and coded by Nino Porcino IZ8BLY in 1999. Before MFSK16 arrived, long-distance (DX) QSOs using digital modes were very unreliable: reliant, as they were, on RTTY and later PSK31. MFSK16 changed all that, using 16 tones and strong error correction. Great for long path DX, but nobody could ever say it was easy to use, never mind slick (quick and agile)!

Over the next few years, many MFSK modes appeared, in fact too many! Most of these were aimed at improving performance on bands with QRM. Most used very strong error correction, some types a poor match for MFSK, and these were very clumsy in QSO, because of long delays.

The next major development, aimed at easy QSOs with a slick turnaround, was DominoEX, designed by Murray Greenman ZL1BPU and coded by Con Wassilieff ZL2AFP, which was released in 2009. Rather than using error correction as a brute-force approach, DominoEX was based on sound research and achieved its performance through carefully crafted modulation techniques that required no error correction. The result was a simpler, easier to tune, easily identified mode with a fast turn-around.

DominoEX is widely used and available in many software packages. A later development by Patrick F6CTE and then Dave W1HKJ added FEC to this mode (THOR) but did not add greatly to performance, and at the same time eroded the fast turn-around. The final DominoEX- related development was EXChat, a version of DominoEX designed specifically for text-message style chatting. While completely compatible with DominoEx, it operates in ‘Sentence Mode’, sending each short over when the operator presses ENTER. EXChat was developed by Con ZL2AFP and released in 2014.

Back in 2013, Con ZL2AFP developed an MFSK mode for LF and MF which used an unusual decoding method pioneered by Alberto I2PHD: a ‘syncless’ decoder, which used a voting system to decide when one tone finished and another began. The first use of this idea was in JASON (2002), which proved to be very sensitive, but very slow, partly because it was based on the ASCII alphabet. The new mode, WSQ2 (Weak Signal QSO, 2 baud) combined the syncless decoder with more tones, 33 in total, and an alphabet specially developed by Murray ZL1BPU, which could send each lower case letter (and common punctuation) in just one symbol, resulting in a very sensitive (-30 dB SNR) mode with a 5 WPM typing speed.

In the subsequent discussion in late 2014, between the developers ZL2AFP and ZL1BPU, it was realized that if the computer had enough processing power to handle it, WSQ2 could be ‘sped up’ to become a useful HF chat mode. This required a large amount of development and retuning of the software to achieve adequate speed was involved, along with much ionospheric simulator and on-air testing used to select the most appropriate parameters.

Tests proved that the idea not only worked well, but it also had marked advantages over existing HF MFSK modes, even DominoEX. As expected, the new mode was found to have superior tolerance of signal timing variation, typically caused by multi-path reception, and would also receive with no change of settings over a wide range of signaling speeds.

So this is how FSQ came about. It uses the highly efficient WSQ character alphabet, IFK+ coding, the same number of tones as WSQ (33), but runs a whole lot faster, up to 60 WPM, and uses different tone spacing. The symbol rate (signaling speed) is modest (six tones per second or less), but each individual tone transmitted carries a surprising amount of information, resulting in a high text transmission speed. And it operates in ‘Chat’ (sentence) mode, which allows the user to type as fast as possible since they type only while receiving.

The ability to send messages and commands selectively has opened a huge array of communications possibilities.

What Makes FSQ Different

Incremental Keying – FSQ uses Offset Incremental Frequency Keying (IFK+), a type of differential Multi-Frequency Shift Keying (MFSK) with properties that make it moderately drift-proof and easy to tune. IFK+ also has excellent tolerance of multi-path reception.

IFK was developed by Steve Olney VK2XV. IFK+ (with code rotation) was proposed by Murray Greenman ZL1BPU and first used in DominoEX. IFK+ prevents repeated same tones without complex coding and provides improved rejection of propagation-related inter-symbol interference. In the context of sync-less decoding, the IFK+ code rotation also prevents repeated identical tones, which could not have been detected by this method.

Efficient Alphabet – In FSQ, a relatively high typing speed at a modest baud rate comes about because the alphabet coding is very efficient. All lower case letters and the most common punctuation can be sent in just one symbol and all other characters (the total alphabet contains 104 characters) in just two symbols. (The alphabet is listed below). This is a simple example of a Varicode, where it takes less time to send the more common characters. The character rate is close to six per second (60 WPM), the same as RTTY, but at only 1/8th of the baud rate. (RTTY has only one bit of information per symbol, 7.5 symbols per character, and wastes a third of its information on synchronization, and despite this, works poorly on HF).

No Sync – Another important factor in the design of FSQ is that no synchronizing process is required to locate and decode the received characters. Lack of sync means that reception is much less influenced by propagation timing changes that affect almost all other modes since timing is quite unimportant to FSQ; it almost completely eliminates impulse noise disruption, and it also contributes to very fast acquisition of the signal (decoding reliably within one symbol of the start of reception). Fast acquisition removes the need for the addition of extra idle characters at the start of transmission, and this leads to a very slick system. Add high resistance to QRM and QRN, thanks to the low baud rate, and you have a system so robust that it does not need error correction.

Cool.

See you on the bands!