Posts Tagged ‘weak signal modes’
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.
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.
New versions K1JT weak signal digital modes
Bob, G3WKW, has passed on this information from Joe Taylor K1JT:
“Date: Fri, 07 Aug 2015 16:28:19 -0400
Several people have asked for an update on development of the “Fast modes” in WSJT and WSJT-X. So here’s a brief summary.
First, a review of some relevant terms and motivations. It’s convenient to think of the various WSJT protocols (“modes”) in two groups:
*Slow modes* — JT4, JT9, JT65, and WSPR. These modes are designed for communication with extremely weak signals — often too weak to be heard. Target propagation modes include EME and long-distance troposcatter on HF-and-up bands, and QRP Dxing on the LF, MF, and HF bands. Relevant signal amplitudes are approximately constant over a minute and more, aside from so-called “libration fading” for EME. Transmit/receive sequences are 1 minute for JT4, JT9, and JT65, and 2 minutes for WSPR.
*Fast modes* — JTMS, FSK441, ISCAT, and JT6M — and now also *FSK315* (implemented in WSJT) and *JT9E* through *JT9H* (implemented in WSJT-X. These modes are made for communication with rapidly varying signals:for example, meteor scatter, ionospheric scatter, airplane scatter, and scatter off the International Space Station. The decoders are designed take advantage of short enhancements of signal strength. T/R sequences are 30 seconds (or sometimes even shorter).
Bill, ND0B, has implemented a trial version of FSK315 in WSJT. Think of this mode as FSK441 slowed down to 315 baud; the bandwidth is therefore narrow enough to make the mode legal in the “CW and data” portion of the 10 meter band. Bill and a few others have been experimenting with FSK315 and also ISCAT-A on 10 meters, under dead-band conditions, using meteors and ionospheric scatter propagation.
I have implemented experimental submodes of the JT9 protocol in the program branch WSJT-X v1.6.1. As with JT4 and JT65, letters following the “JT9” designator indicate increased spacings between the FSK tones. Traditional JT9 (now also called JT9A) has tone spacing 1.736 Hz, so the signals used at HF and below have total bandwidth 9*1.736 = 15.6 Hz. The widest of the new submodes, JT9H, has tone spacing 200 Hz and therefore bandwidth 9*200 = 1800 Hz.
When used with the standard 1-minute periods, the wide JT9 submodes should be useful for the same purposes as the wide JT4 submodes: microwave EME, for example, where libration fading can cause Doppler spreading of 100 Hz or more. Used in this way, all JT9 submodes are “slow” modes; they use 1-minute T/R periods and keying rate 1.736 baud, and they send the full 85-symbol message protocol in 85/1.736 = 48.96s.
Optionally, the wide JT9 submodes can now also use “fast” keying rates equal to their tone spacing. “Fast JT9H”, for example, uses keying rate 200 baud, so the full message protocol is transmitted in 85/200 = 0.425s. The message is sent repeatedly for the full Tx period, in the same way as done for the other fast modes.
The fast JT9 submodes should be very effective for meteors and ionoscatter propagation, especially on the 6 meter band. Sensitivity should be similar to ISCAT, or perhaps slightly better. Because JT9 includes strong forward error correction, decoding results are like those for all the slow modes: you should see messages exactly as they were transmitted, or nothing at all.
Tests of the fast JT9 submodes are currently under way, with excellent results.
— 73, Joe, K1JT”