Presentation on theme: "Working the World with WSJT-X (JT-65 & JT-9)"— Presentation transcript:
1 Working the World with WSJT-X (JT-65 & JT-9) How many here work this? (Fish stories)Weak Signal Joe Taylor (WSJT)Discovered capabilities when I got into EME about 2 years agoAllowed me to work off the moon on 2 meters when I couldn’t even hear the stationThen discovered that folks were using it on HFWSJT consists of 2 modes – JT65 & JT9 (you choose which one you are going to use)One base freq on each band where it is used … that is all .. Results in a 3 KHz windowIMPORTANT – Anything you receive across 3 KHz band is posted on PSK ReporterWSJT screen consists of 3 parts (Waterfall – Control – Station ID)
2 What are the WSJT modes of JT65 & JT9 Both are digital modes optimized for extremely weak signal communications.JT65 uses a series of 64 tones for data plus a sync tone.JT9 uses a series of 8 tones for data plus a sync tone (modulation 9-FSK)Hardware requirements are a computer, computer to radio interface, and aSSB transceiver that will operate on your frequency of choice.Note: If you are set up to run the digital modes like FLDIGI & MMSSTV,you most likely have everything that you need.* You choose what mode you are going to use based on personnel preference & band traffic
3 Weak Signal by Joe Taylor (WSJT) In July, I had the privilege of meeting Joe at the Symposium of Amateur Radio Astronomers held at the National Radio Astronomy Observatory in Green Bank, West Virginia.Joe Taylor discovered the first Pulsar in a binary star system. He has used this to make high-precision tests of general relativity and in 1993, received a Nobel Prize in Physics for this discovery* A few details about Joe Taylor* At this time JT65 & JT9 are the pemier weak signal decoding programs on the amateur bands.* They use revolutionary concepts in probilility, forward error detection, and long term integration to copy a msg 100% when it is too weak to be heard.Joe Taylor, K1JT created the set of weak signal protocols used in the WSJT system for EME. This has enabled stations using a single Yagi & 50 watts to work larger stations off the moon. He then created the WSPR application used by thousands of amateurs world wide as a realtime propagation indicator on HF. His most recent accomplishment is WSJT-X, a system that enables stations running low power and compromise antennas to make world wide contacts.All of this is FREE!
4 Quotes from forums on the Web We've all heard the old saying, oft repeated in these review pages (usually about antennas), "if you can’t hear …them you can’t work them". Well...welcome to the new world of WSJT, I can't hear them but I work them anyway. WB0FDJJoe is adding 3dB of gain every month. SP9TTGWSJT, and the modes contained therein (JT65/WSPR/JT2/JT4/PSK441), are with little doubt, the most cutting edge weak signal modes afforded to us as Amateurs. JT65 makes it possible to work DX that I never thought was possible with a compromise antenna and a QRP-only rig (FT-817ND) as my main/only radio. KB2HSHComments from E-Ham and other forums on the webFirst two are my favotites (I don’t kow about the 2nd one)!Hold up FT-817Although Joe provides the software free of charge, it does not come without cost. His program is so addictive that you will find yourself spending hours in the shack exploring the fascinating world of weak signals WB4ECRJT65, and JT9 that followed, enabled me to make WAS in a month on the air, and DXCC within a couple of months, all while running 5 watts QRP to a horrible end-fed antenna stapled to trees WB4SON
5 What is the attraction of the Weak Signal Modes such as JT-65, JT-9 and others?Large antennas are NOT required (a short whip on back of rig works)High power is not needed ( 2 to 5 watts will make lots of contacts)Narrow bandwidth (JT-65 is 200 Hz, JT-9 < 30 Hz)So just how does JT-65 & JT-9 stack up against the other modes …* Lets talk about JT65 & JT9 a bitAnd lets discuss how they compare to other communications modesSince I have you here … lets even talk a little about the other Comminication modes.QST article in the December 2013 issue comparing different modes (go over)Note – especially SSB compared to FM (relate story of Mount Davis)Stress signal levels at the receiverCW – always the standard for weak signal (radio/brain system)PSK31 only requires halfJT65 & JT9 about 12%*** Levels required to obtain an intelligible output
6 Where does JT65 & JT9 take place? Static crashRemember that the WSJT modes only take place at one spot on each band.Let’s take a look at traffic across a typical portion of 20 meters & how WSJT fits inNoiseRTTYScannerWall WartIonosphericPingerCWHDGCWSJTSSB voicePSK31
7 Why is JT65 so efficient at delving deep into the noise floor? 65 tone Frequency Shift Keying- Much more efficient then on/off keying as in CWNarrow bandwidth- 200 Hz for JT65 <30 Hz for JT9JT65 message much more compact then a CW messageIn CW – “W3SMF WA3USG FN10” takes 170 bits (bit=key down dot interval)In JT bitsData is sent with an redundancy ratio of 5.25 to 1 and is repeated throughout the message using a mathematical algorithm developed based on probability (Reed Solomon Codes).A sync pulse starts each transmit cycle as a definitive reference.Data tones are on line long enough for the receiving computer to perform quasi long term integration in order to detect them below the noise floor.Transmit and receive cycle are both automatic and dependent upon computersat each end being in sync within 2 seconds of each other.* Lets get right down to the nittey gritty of why these modes work so well.
8 An example of the results … Explain operations from Savannah GeorgiaPSK Reporter
9 WSJT Modes – Structure of a QSO Both JT65 & JT9 consist of the minimum information needed to complete a validQSOThe typical QSO takes about 6 minutesConsists of a minimum of 6 T/R exchanges, each taking 1 (one) minute. Thisis broken down into 50 seconds to send the data and 10 seconds for the otherstation to decide on how he or she is going to respond.1. Station 1 Calling CQ along with a location (eg: CQ WA3USG FN102. Station 2 answering along with a location (eg: WA3USG W3SMF FM19)3. Station 1 responding with a signal report (eg: W3SMF WA3USG -074. Station 2 responding with a signal report (eg: WA3USG W3SMF -04)5. Station 1 acknowledging reception of signal report (eg: W3SMF WA3USG RRR)6. Station 2 acknowledging receipt & closing down QSO with a 73(eg: W3SMF WA3USG 73)
17 In Summary Both Modes of WSJT (JT65 & JT9) are FUN! Performance is amazing.JT9 is a lot narrower then JT65 and goes a bit deeper into the noise …use it! You can fit a lot more QSO’s into the 3 KHz allocated space!Receive & Transmit stability is required.There seems to always be activity on the WSJT recommended frequencies(even when the band is “dead”).It takes a bit of time & effort to set the software up and master it but anyonehere can do it. The effort is part of the challenge and adds to thesatisfaction of working great DX with just a few watts!
Your consent to our cookies if you continue to use this website.