Posts Tagged ‘ft8’
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.
|FT8 waterfall on 10m|
PSK reporter had me being spotted in the U.S. and Europe as well.
|9K2OW in the log|
This evening I decided to settle into the shack and once again get on FT8 to see what was happening. I went directly to 40m and set my power to 70 watts. As a side note funny thing about 40m I used to bother the washer machine and an office light would turn on and off but for some reason not anymore. Anyway, this post was about a very nice FT8 contact I made. I was calling CQ well to be more accurate my computer was calling CQ. Right out of the blue I had a call from 9K2OW in Kuwait!!
With a couple of mouse clicks and he was in the log. Recently I have been reading some positive and negative opinions regarding FT8. Personally, I like to stay neutral when I read these posts maybe that is the Canadian in me but I do know I had a blast having Kuwait answer my CQ call on 40m. It was a short but good evening on ham radio!
I was on the radio this afternoon and decided to give FT8 a try on 20 meters. I made some contacts in the U.S., France, Germany and Spain. Then out of the blue, I had a station from Japan call me and I did not notice any J stations I was decoding but I was very pleased regarding the contact. Then once again out of nowhere another J is calling me and I made my second contact. I took a look at PSK reporter to see where my FT8 signal was being spotted. I was shocked to see not only Japan but also Hawaii. A very nice time on the radio today.
With three seasons of FT8 under its belt, there’s no doubt that it's taken over as the number-one mode for the 6m band ... there are very few traces of CW or SSB to be found.
What it hasn’t taken away, is the magic!
For the most part, this summer’s conditions from the west coast were pretty normal, except for when they weren’t ... and when they weren’t, they were pretty spectacular!
The spectacular parts were highlighted by one particularly unique contact that can only be attributed to some heads-up operating skills, a little help from FT8 ... and the unpredictability of Sporadic-E.
On June 20, at 0056Z, K7CW (Paul), south-west of Seattle, nudged his signal all the way to Hong Kong, more specifically, to VR2ZXP’s crowded apartment building. But that’s not the incredible part. That happened when Paul heard and exchanged signal reports with Alfred’s tiny station!
|Not the best location for weak signal 50MHz DX!|
"As I told to Paul, it’s a hard job to be a ham in VR2 Hong Kong especially for the DX. Hong Kong is a high density population city. 99% people are living in apartment only. The housing price here is crazy around US$1800 per sq. feet. Neighborhoods always complain why we setup antennas out of our windows and produce radiation to affect their health. So, what we just can do is to use a small whip with QRO for the QSO. Besides, interference is also serious. Thousands of air conditioner is surrounding me and a power station 132kV to 11kV is just faced to me in 1km away. Here the noise level on low HF band at night is S9."
As indicated above, Alfred’s station is located in a typical high-rise apartment, surrounded by numerous others, with no room for antennas. His solution is to clip a short (60”) whip antenna, horizontally mounted on his balcony railing, similar to this one from 20 years ago ... before being surrounded by noisy high-rise apartment buildings!
I’m not sure which is the most spectacular part of this contact ... that Alfred could detect Paul’s signal in such a noisy environment using such a small makeshift antenna or that Paul was able to copy the tiny signal coming from uptown Hong Kong.
|K7CW's 9el - 50' Yagi at 80'|
Long openings like this occur very rarely, making them even more thrilling and can cause even the most experienced 6m DXer’s mouse-hand to tremble with excitement!
|Some of VE7DAY's wallpaper from the May 31st opening.|
Others up and down the west coast also filled their log pages with ‘new ones’ ... unfortunately my exciter was on the workbench while replacing the screen so I never knew what I had missed until some time later ... probably just as well. I guess I must have been pretty naughty at some point, as the 6m gods definitely singled me out for special punishment that morning.
Once the exciter was back together I was able to catch a few good openings myself, the best of which was early on the morning of June 23 when I was able to work SV9CVY (Crete), SV1DH (Greece) and IS0AWZ (Sardinia).
Crete and Sardinia gave me DXCC #89 and #90. Three days later, during a nice opening to the southern states, J68HZ in St. Lucia snuck through the QRM for #91. After a further three days, on June 29, another very early opening put 8 more Europeans in the log including HA8CE (Hungary) and YU7EF (Yugoslavia) for #92 and #93 respectively.
The band also produced several long openings to Asia, usually in the late afternoon hours. Several contacts were made with South Korean stations, China and dozens with Japan.
All told, the band produced some exciting activity this summer. Countries worked here were:
JA, JW, TG, V31, J68, LA, SM, SV9, SV, IS0, EA, HA, YU, F, 9A5, BG, HL, EA8. Certainly FT8 had much to do with a good portion of the action but it is difficult to say just how much. Many of the Europeans were very strong and could have easily been worked on CW in a matter of a few seconds, rather than the 60 - 75 seconds required for a valid FT8 exchange, assuming there are no repeats. But it's contacts like Paul and Alfred's that continue to validate the special name given to the band ... you just never know what might tricks will be next.