Posts Tagged ‘Digital modes’

Interested in Amateur Radio Digital Mode FT8 Operations?

A VISUAL + AUDIO AIR CHECK OF DIGITAL MODE FT8 QSOs, ON THE 30-METER BAND

Here is a video capture of the reception and transmission of many digital FT8-mode amateur radio high-frequency (HF; Shortwave) communication signals. This video is a front-seat view of the software operation performed at the radio room of amateur radio operator, NW7US, Tomas Hood.

The software packages demonstrated are installed and operational on a modern personal computer. The computer is connected to an Icom IC-7610 radio transceiver, controlled by the software. While there is no narration in the video, the video provides an opportunity for you to see first-hand how typical FT8 operations are performed. The signals can be heard.

The frequency used for the FT8 communication in this video is on or about 10.136 MHz, in the 30-Meter shortwave amateur radio allocation (or, band). As can be seen, the 30-Meter band was active at this time of day (0720 UTC, onward–local nighttime).

In this video you see (and hear) NW7US make two-way contacts, or QSOs, with stations from around the country and the world.

There are amateur radio operators within the amateur radio community who regard the FT8 digital mode (FT8 stands for “Franke-Taylor design, 8-FSK modulation“, and refers to the mode created by Joe Taylor, K1JT and Steve Franke, K9AN) as robotic (automatic, automated, and unattended) computer-to-computer communications, and not ‘true’ human communications–thus negating the spirit of ham radio. In other words, FT8, in their opinion, is not real amateur radio. While they pontificate about supposed automated computer communications, many of those holding this position have not installed and configured the software, nor tried communicating with the FT8 digital mode. They have perhaps formed their anti-FT8 opinion in a vacuum of knowledge. (This writer has other issues with FT8, but not on this point–see below)

As you watch the video linked in this article, consider these concepts:

+ A QSO is defined (as per common knowledge–see below) as the exchange of at least the minimum information needed as set by the requirements of a particular award, or, as is defined by law–for instance, a QSO would have at least an exchange of the legal call sign assigned to the radio station and/or control operator, the location of the station making the transmission, and a signal report of some kind about the signal received from the other transmitter at the other end of the QSO.

+ Just how much human involvement is required to make a full FT8 QSO? Does WSJT-X software run all by itself, with no human control? Is WSJT-X a robot, in the sense that it picks a frequency, then initiates or answers a CQ call automatically, or is it just powerful digital-mode software that still requires human control?

The video was captured from the screen of the PC running the following software packages interacting together as a system:

+ WSJT-X: The primary software featuring the digital mode, FT8. (See below for some background on WSJT-X software.)

+ JTAlert: Provides several audio and visual alert types based on decoded Callsigns within WSJT-X.

+ Log4OM, Version 2: A full-featured logging program, which integrates well with WSJT-X and JTAlert.

+ Win4IcomSuite: A full-featured radio controlling program which can remote control rigs, and provide control through virtual communication port-sharing.

+ Com0Com: The Null-modem emulator allows you to create an unlimited number of virtual COM port pairs and use any pair to connect one COM port based application to another. Each COM port pair provides two COM ports. The output to one port is the input from other port and vice versa.

As mentioned, above, the radio used for the communication of FT8 at the station, NW7US, is an Icom IC-7610 transceiver. The antenna is an off-center fed dipole that is over 200 feet in total length (end-to-end measurement).

Some Notes:

About WSJT-X

WSJT-X is a computer program used for weak-signal radio communication between amateur radio operators, or used by Shortwave Radio Listeners (SWLers; SWL) interested in monitoring the FT8 digital communications between amateur radio operators. The program was initially written by Joe Taylor, K1JT with Steve Franke, K9AN, but is now open source and is developed by a small team. The digital signal processing techniques in WSJT-X make it substantially easier for amateur radio operators to employ esoteric propagation modes, such as high-speed meteor scatter and moonbounce.

WSJT-X implements communication protocols or “modes” called FST4, FST4W, FT4, FT8, JT4, JT9, JT65, Q65, MSK144, and WSPR, as well as one called Echo for detecting and measuring your own radio signals reflected from the Moon. These modes were all designed for making reliable, confirmed QSOs under extreme weak-signal conditions. JT4, JT9, and JT65 use nearly identical message structure and source encoding (the efficient compression of standard messages used for minimal QSOs). They use timed 60-second Transmit/Rreceive (T/R) sequences synchronized with UTC (Universal Time, Coordinated). JT4 and JT65 were designed for Earth-Moon-Earth communications (EME, or, moonbounce) on the Very-High Frequency (VHF), Ultra-High Frequency (UHF) and microwave bands. JT9 is optimized for the Medium-Frequency (MF) and High-Frequency (HF) bands. It is about 2 dB more sensitive than JT65 while using less than 10% of the bandwidth. Q65 offers submodes with a wide range of T/R sequence lengths and tone spacings.FT4 and FT8 are operationally similar but use T/R cycles only 7.5 and 15 seconds long, respectively. MSK144 is designed for Meteor Scatter on the VHF bands. These modes offer enhanced message formats with support for nonstandard call signs and some popular contests. (The MSK in MSK144 stands for, Multiple Frequency Shift Keying.)

FST4 and FST4W are designed particularly for the Low-Frequency (LF) and MF bands. On these bands, their fundamental sensitivities are better than other WSJT-X modes with the same sequence lengths, approaching the theoretical limits for their rates of information throughput. FST4 is optimized for two-way QSOs, while FST4W is for quasi-beacon transmissions of WSPR-style messages. FST4 and FST4W do not require the strict, independent time synchronization and phase locking of modes like EbNaut.

As described more fully on its own page, WSPR mode implements a protocol designed for probing potential propagation paths with low-power transmissions. WSPR is fully implemented within WSJT-X, including programmable band-hopping.

What is a QSO?

Under the title, CONTACTS, at the Sierra Foothills Amateur Radio Club’s 2014 Technician Class webpage, https://www.hsdivers.com/Ham/Mod15.html, they teach,

An amateur radio contact (called a QSO), is an exchange of info between two amateur radio stations. The exchange usually consists of an initial call (CQ = call to all stations). Then, a response from another amateur radio operator, and usually at least a signal report.

Contacts can be limited to just a minimal exchange of call signs & signal reports generally between amateurs previously unknown to each other. Very short contacts are usually done only during contests while longer, extended ‘rag chews’ may be between newly met friends with some common interest or someone you have known for a long time.

Wikipedia has an entry for QSO, too.

My Issue With FT8 and WSJT-X

I have written in the past, on this website, about an issue that came about during the course of the development of the WSJT-X software package. The development team decided to widen the slice of ‘default’ (pre-programmed) frequencies on which to operate FT8. The issue was how the choice of new frequencies was made, and what choices were implemented in an upcoming software release. Read more about all of this, in these three articles:

+ Land (er, FREQUENCY) Grab (Part 1)

+ One Aspect of Amateur Radio: Good Will Ambassadors to the World

+ In Response — Can’t We All Just Get Along?

Has this issue been resolved? For now, yes. There appears to be more coordination between interested groups, and the proposed new frequencies were removed from the software defaults in WSJT-X. At least, up to this point, at the time of publishing this article.

..

One Aspect of Amateur Radio: Good Will Ambassadors to the World

This article is part two of the series taking a look at band plans and gentlemen agreements.
See part one, here: Land (er, FREQUENCY) Grab.  See part three, here: In Response — Can’t We All Just Get Along?

Displaced and Marginalized

There are some unhappy amateur radio operators in the world of shortwave operations. Users of Morse code, and digital modes other than the highly-popular modes engineered by Joe Taylor, K1JT, feel displaced on the many amateur radio bands where Joe’s wildly-popular mode FT8 has erupted.

Joe (born March 29, 1941), is a friend of hams everywhere, and is an American astrophysicist and Nobel Prize in Physics laureate (https://g.nw7us.us/2Ptquv1) for his discovery with Russell Alan Hulse of a “new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation.”

Many have asked questions like, “Did Joe Taylor K1JT Destroy Amateur Radio? Did Joe Taylor K1JT, Nobel Laureate and noted friend of hams everywhere, accidentally destroy amateur radio?” This question remains relevant, even as more and more FT8 operators take to the HF bands to chase wallpaper and awards.

FT8 Has Validity and Usefulness

Full disclosure: I administer a Facebook group for FT8 and FT8-related modes, because I believe that the mode has a valid place in our amateur radio technology portfolio.  Here is the Facebook group URL, if you would like to join the fun: https://www.facebook.com/groups/FT8.FT4.HF.6m/. Understand, I have used and will continue to use FT8.

Because it has a place, it stands to reason that everyone should become more aware of the impact of using FT8 on the bands. It also stands to reason that it should be used ethically, and in the best spirit of amateur radio.

Many amateur operators use the FT8 digital mode as a novelty when there isn’t much else happening on amateur radio shortwave bands. One of the great things about it is that you can tell when a band is open–even though you don’t hear any other signals of other modes on the band in question, you very well may hear the roar of FT8 on the band where propagation actually exists to somewhere else than your QTH.

Others use it to finally get their DXCC, or WAS, or other award and wallpaper. This is especially popular during this season of the sunspot cycle where there are no sunspots–propagation is limited to lower-HF amateur bands because there’s just not enough solar activity to energize the ionosphere enough to open up the higher segment of shortwave.

FT8 Has Limitations

Can FT8 be used for two-way conversations? No. However, the JS8CALL digital mode is designed from the FT8 mode, by changing the protocol in a way that allows free text. It is designed for ragchewing and the new version 2.0 offers three modes of chat with 50 Hz and 16 wpm, 80 Hz and 24 wpm, and the turbo mode at 160hz and 40wpm with turbo only having a 6-second turn around time. The designated frequency is 7.078, which many find much nicer to use.

However, many find JS8CALL combersome, and non-intuitive.  How fast and how reliably can it handle critical messages, say, during an emergency?  I’m sure the software will improve, but how good is the protocol?

A mode such as Olivia has been field proven, and time tested.  It can reliably handle traffic.

The Rant

During the early days of widespread FT8 operation that came with the first public non-Beta release of FT8-equipped WSJT-X software, I tried to reason with the FT8 development leadership team. I made a polite attempt at explaining how incredibly rude they were in purposefully programming into the software the default operating frequencies such as 7.075, 14.075, and so on.

One of the main leaders of that team slammed me and stated that “we only suggested those frequencies; the operator is free to change them.” Additionally, he stated that the team used a common QSO/Mode spotting website to see what digital modes or other operations (like CW) were sparser. They perceived that the frequencies they proposed where no longer active because they saw few if any spots. They thought that no one would care.

I explained that a single website-spotting strategy was illogical and very lazy. This is true for several reasons, at least.

I guess you have to have a Ph.D. to know better than any average ham who went by gentleman’s agreements. I have an extremely dim view of JT and his disciples. CW is not the only operating group he’s engineered out of traditional slices of spectrum. Olivia, and other modes, now have been pushed down into PSK subbands, and everyone is feeling the crowding. As far as my thinking of FT8, well, it is radio, but it doesn’t foster goodwill and building serious communications skill. IMHO.

Play Nice, Be Positive and Polite. Smile.

I’ve received wise counsel from a number of fellow amateur radio operators.  They implore us to not promote hostility between “us and them.”  That even though the WSJT team is playing the playground bully, we should not be vengeful, but polite and willing to negotiate in good faith.

If we don’t play nice with the bully then the bully won’t play with us.  And, the general public will side with the bully because the bully has the nice toys…

Good negotiations, though, take a willingness by both sides, so that conversation evolves,  resulting in positive, cooperative actions embraced by both parties. There are other amateur radio operators who have made attempts to open up talks with Joe and crew.  What are the results, so far?

We can hope that Joe Taylor and his group of developers and leadership take a proactive role and join a conversation that is with a wider group of amateurs than just the WSJT enthusiasts.  We hope that they will play fairly, and cooperatively, with the rest of the amateur radio community.

 

 

Tomas, NW7US

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.

Land (er, FREQUENCY) Grab (Part 1)

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, NW7US

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.

From Lightning Comes a New Icom IC-7610 (First Transmission)

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!

Olivia Digital Mode (1000 Hz) on Twenty Meters – A Simple Video

The Olivia digital mode on HF radio is a mode capable of two-way chat (QSO) communication (keyboard to keyboard, like RTTY) over long-distance shortwave (HF) ionospheric propagation paths, especially over polar regions.

If you are interested in more than a logbook QSO (such as is typical with FT8 and other propagation-checking modes) but want to chat with other hams around the world using digital modes, consider Olivia as one option.

This video captures a few moments of two-way conversation on the Twenty-Meter band, up in the sub-band where 1000-Hz digital modes are commonplace. More narrow-bandwidth settings are used in a lower subband in the digital slice of Twenty Meters. More details about the mode are in the files section of this website: http://OliviaDigitalMode.org.

In 2005, SP9VRC, Pawel Jalocha, released to the world a mode that he developed starting in 2003 to overcome difficult radio signal propagation conditions on the shortwave (high-frequency, or HF) bands. By difficult, we are talking significant phase distortions and low signal-to-noise ratios (SNR) plus multipath propagation effects. The Olivia-modulated radio signals are decoded even when it is ten to fourteen dB below the noise floor. That means that Olivia is decoded when the amplitude of the noise is slightly over three times that of the digital signal!

Olivia decodes well under other conditions that are a complex mix of atmospheric noise, signal fading (QSB), interference (QRM), polar flutter caused by a radio signal traversing a polar path. Olivia is even capable when the signal is affected by auroral conditions (including the Sporadic-E Auroral Mode, where signals are refracted off of the highly-energized E-region in which the Aurora is active).

Currently, the only other digital modes that match or exceed Olivia in their sensitivity are some of the modes designed by Joe Taylor as implemented in the WSJT programs, including FT8, JT65A, and JT65-HF–each of which are certainly limited in usage and definitely not able to provide true conversation capabilities.  Olivia is useful for emergency communications, unlike JT65A or the popular FT8. One other mode is better than Olivia for keyboard-to-keyboard comms under difficult conditions: MT63. Yet, Olivia is a good compromise that delivers a lot. One reason for this is that there are configurations that use much less bandwidth than 1000 Hz. 16 tones in 250 Hz is our common calling-frequency configuration, which we use lower down in the Twenty-Meter band, with a center frequency of 14.0729 MHz.

Q: What’s a ‘CENTER’ Frequency? Is That Where I Set My Radio’s Dial?

For those new to waterfalls: the CENTER frequency is the CENTER of the cursor shown by common software. The cursor is what you use to set the transceiver’s frequency on the waterfall. If your software’s waterfall shows the frequency, then you simply place the cursor so that its center is right on the center frequency listed, above. If your software is set to show OFFSET, then you might, for example, set your radio’s dial frequency to 14.0714, and place the center of your waterfall cursor to 1500 (1500 Hz). That would translate to the 14.0729 CENTER frequency.

The standard Olivia formats (shown as the number of tones/bandwidth in Hz) are 8/250, 8/500, 16/500, 8/1000, 16/1000, and 32/1000. Some even use 16/2000 for series emergency communication. The most commonly-used formats are 16/500, 8/500, and 8/250. However, the 32/1000 and 16/1000 configurations are popular in some areas of the world (Europe) and on certain bands.

These different choices in bandwidth and tone settings can cause some confusion and problems–so many formats and so many other digital modes can make it difficult to figure out which mode you are seeing and hearing. After getting used to the sound and look of Olivia in the waterfall, though, it becomes easier to identify the format when you encounter it. To aid in your detection of what mode is being used, there is a feature of many digital-mode software implementation suites: the RSID. The next video, below, is a demonstration on how to set the Reed-Solomon Identification (RSID) feature in Ham Radio Deluxe’s Digital Master 780 module (HRD DM780).

I encourage ALL operators, using any digital mode such as Olivia, to TURN ON the RSID feature as shown in this example. In Fldigi, the RSID is the TXID and RXID; make sure to check (turn on) each, the TXID and RXID.

Please, make sure you are using the RSID (Reed Solomon Identification – RSID or TXID, RXID) option in your software. RSID transmits a short burst at the start of your transmission which identifies the mode you are using. When it does that, those amateur radio operators also using RSID while listening will be alerted by their software that you are transmitting in the specific mode (Olivia, hopefully), the settings (like 8/250), and where on the waterfall your transmission is located. This might be a popup window and/or text on the receive text panel. When the operator clicks on that, the software moves the waterfall cursor right on top of the signal and changes the mode in the software. This will help you make more contacts!

RSID Setting:

+ NOTE: The MixW software doesn’t have RSID features. Request it!

Voluntary Olivia Channelization 

Since Olivia signals can be decoded even when received signals are extremely weak, (signal to noise ratio of -14db), signals strong enough to be decoded are sometimes below the noise floor and therefore impossible to search for manually. As a result, amateur radio operators have voluntarily decided upon channelization for this mode. This channelization allows even imperceptibly weak signals to be properly tuned for reception and decoding. By common convention amateur stations initiate contacts utilizing 8/250, 16/500, or 32/1000 configuration of the Olivia mode. After negotiating the initial exchange, sometimes one of the operators will suggest switching to other configurations to continue the conversation at more reliable settings, or faster when conditions allow. The following table lists the common center frequencies used in the amateur radio bands.

Olivia (CENTER) Frequencies (kHz) for Calling, Initiating QSOs

Current Olivia Digital Mode Calling Frequencies

Current Olivia Digital Mode Calling Frequencies on Shortwave (HF)

It is often best to get on standard calling frequencies with this mode because you can miss a lot of weak signals if you don’t. However, with Olivia activity on the rise AND all the other modes vying for space, a good deal of the time you can operate wherever you can find a clear spot–as close as you can to a standard calling frequency.

Note: some websites publish frequencies in this band, that are right on top of weak-signal JT65, JT9, and FT8 segmentsDO NOT QRM weak-signal QSOs!

We (active Olivia community members) suggest 8/250 as the starting settings when calling CQ on the USB frequencies designated as ‘Calling Frequencies.’ A Calling Frequency is a center frequency on which you initially call, ‘CQ CQ CQ. . .’ and then, with the agreement of the answering operator, move to a new nearby frequency, changing the number of tones and bandwidth at your discretion. Even though 8/250 is slow, the CQ call is short. But, it is narrow, to allow room for other QSOs nearby. It is also one of the best possible Olivia configurations for weak-signal decoding.

Let’s Call CQ – QSO Today Episode 184 with NW7US

I got a Skype call a few weeks ago from Eric, 4Z1UG–the creator and host of the QSO Today Podcast–during which he asked me about how and why I got into amateur radio.  Here’s the result.

Eric writes,

We talk a lot about the band conditions due to the Sunspot cycle. Most of it on Facebook and other places is about how “dead” the bands are at this point. We all can’t wait until the cycle starts to rise and we will be making contacts with little effort. I remember in my conversation with Chuck Adams, K7QO in Episode 58, that he really enjoys operating is “Pigrig”, one watt, CW transceiver on 20 meters. When I asked him, (I liberally paraphrase) “but Chuck, the bands are dead. How does that work for you?”. His reply was that while most hams are listening to the bands, he calls CQ until he gets a reply. Works every time.

My QSO this week is with Tomas Hood, NW7US, who has years of expertise in propagation and Solar activity. He is the propagation editor of more than a few radio magazines and websites. In our post-recording conversation we discussed this phenomenon of listening and not calling CQ. I even had this idea that maybe one of the reasons that the digital modes are so successful is because they “beacon”, as part of the whole digital experience, the same as calling CQ. This is why they make contacts. From what I see, looking at PSK Reporter, hams are making lots of contacts worldwide using the digital modes. While SSB may not be working so well, CW and the digital modes seem to work fine.

I like to work on my bench or make the podcast while listening to the bands. Jeff Damm, WA7MLH, in Episode 177, says that he will put his keyer in CQ mode while he is working on a new radio. Invariably, sometimes after many minutes, he gets a reply. Great idea Jeff!

73,

Eric, 4Z1UG

Episode 184 can be found here: https://www.qsotoday.com/podcasts/nw7us

Highlights of Episode 184:

Tomas Hood, NW7US is the propagation editor of a number of shortwave and amateur radio magazines, and has a wide variety of websites, that grew out of his love for all things radio, and for listening on the bands to far off DX and commercial broadcast stations. Tomas shares his understanding of propagation and the lessons we can learn from listening, really listening to the QSOs and exchanges during contest operation.

All of the QSO Today episodes are great.  I enjoy hearing about many different hams.  Do check out all of the episodes that Eric has published.

73 de NW7US dit dit

 

What Got You Interested in Radio? What Hooked You? (Story Time, with Video)

What got you interested in radio? What hooked you?

I’ve been asked, “What got you interested in radio, space weather, and the science of radio-wave propagation?”

Here’s a short answer as to why (and when) I became a radio enthusiast. It all started…

https://www.youtube.com/watch?v=0XBth62JgwA

The following picture is of my first shortwave radio, discovered in my home sometime between 1971 and 1973: a Sony portable transistorized four-band radio receiver. This was my very first shortwave radio (well, truthfully, it was my dad’s). This radio is responsible for my love of radio, electronics, and communications.

Sony Portable 4-Band Radio - the model 7F-74DL (my First Radio)

Sony Portable 4-Band Radio – the model 7F-74DL (my First Radio)

I still use this, sometimes, when listening to late-night AM-broadcast-band-radio DX. It is horrible for shortwave radio listening, as it has no noise blanker. For MW (Medium-wave) AM Broadcast DXing at night, it is excellent. The internal bar antenna is very directional so I can rotate the radio around until I get the best reception of some station. Back when I was a child, that made the radio very fun to use.

This next radio is a really capable military surplus radio circa WWII or shortly after (the late 1940s, early 1950s). This radio was my world starting around 1975. From Medium-wave to Shortwave, this radio could hear a pin drop around the world! Many late nights when I was supposed to be sleeping, I was up with the light dimmed and the tubes singing signals from exotic places.

Espey R366 Tube Receiver (my Second Radio)

Espey R366 Tube Receiver (my Second Radio)

What is your story?73 de NW7US

Addendum:
https://www.youtube.com/watch?v=y8bBM9Dy38o


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