Posts Tagged ‘Digital mode’
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).
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:
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.
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.
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 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.
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.
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.
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.
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!
+ 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
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 segments. DO 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.
As some of you know, I have had some differences of opinion regarding the selection of frequencies chosen by the FT8 creators and advocates. Regardless, I do still use the mode. Here is proof:
Go ahead and share, if you would. And, please subscribe to my YouTube channel, as I will be creating many how-to videos in the near future.
Thanks and 73 … de NW7US
My friend Alf, LA2NTA, has sent med these screenshots from when he has been operating FT8. The first image is when operating 10 meters and took place early in November.
|Two of LA2NTA CQs being received by himself on 10 meter (in red)|
It shows how his own CQ comes back to him at 10.54.00 and at 11.00.00 and is decoded in his own receiver.
The second example is from 20 meters and took place just a few days ago.
|LA2NTA CQ being received by himself on 20 meter (in red)|
|FT8 band on 10 meters showing some form of noise all over the band|
Calling all Olivia-mode operators with experience using the Olivia digital mode in all areas of the world:
Please join our Facebook group at the following link. We are discussing important operational changes!
If you are on Facebook, and interested in the Olivia HF radioteletype chat mode, please join the community group at the following link: https://www.facebook.com/groups/olivia.hf/
If you want to join our discussion by way of the Olivia group on Groups.io, please feel free to spread the news, and also to subscribe to that group email reflector. We’ll start discussions, soon. Here’s the link: https://groups.io/g/Olivia
OLIVIA (Also, Olivia MFSK) is an amateur digital radioteletype mode designed by Pawel Jalocha, SP9VRC, starting in 2003, and in use by 2005. The Olivia-mode goal was to be effective even in poor propagation conditions on the high frequencies (shortwave).
OLIVIA can decode well under noise, propagational fading (QSB), interference (QRM), flutter caused by polar path propagation and even auroral conditions and sporadic-E. Olivia uses a 7-bit ASCII alphabet. There were a handful of amateur digital modes that were derived from Olivia, including RTTYM and PAX.
Outside of amateur radio two-way communication, this mode is utilized during the tests run by the VoA every weekend. See the VoA RadioGram website, VoARadiogram.net, for the schedule.
The first on-the-air tests were performed by two radio amateurs, Fred OH/DK4ZC and Les VK2DSG on the Europe-Australia path in the 20-meter amateur band. The tests proved that the protocol works well and can allow regular intercontinental radio contacts with as little as one watt RF power. Since 2005 Olivia has become a standard for digital data transfer under white noise, fading and multipath, flutter (polar path) and auroral conditions.
Since Olivia signals can be decoded even when received signals are extremely weak, (signal to noise ratio of -14 dB), 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 either the 16/500 or 32/1000 modes and then switch to other modes to continue the conversation. The following table lists the common center frequencies used in the amateur radio bands.
The traditional channels are now under heavy use by newer modes. Thus, this Olivia group is working on refiguring the strategy for continued use and channelization. Please join us for discussion.
Tomas / NW7US