>From W7GJ ADDITIONAL TIPS FOR USING JT65 IN WSJT VERSION 5.9.2
* TUTORIAL. Study the new tutorial at http://pulsar.princeton.edu/~joe/K1JT/Tutorial_590.txt * DEMO. K1JT has provided DEMO files on his website, so you can practice decoding actual .wav files. There are three secrets to success in learning how to efficiently and accurately use the JT65 software to decode weak signals: 1. PRACTICE 2. PRACTICE 3. PRACTICE You can often find local stations willing to practice with you, by going to http://www.chris.org/cgi-bin/jt65eme Please remember that it is NOT NECESSARY to have a computer interface just to practice receiving files! Just run audio from the receiver headphone jack to the LINE INPUT on the computer sound card jack, download the software and have at it! Practice makes perfect! * GRID LOCATOR ENTRY. Make sure you type your grid locator with the last two letters in LOWER CASE (for example, "DN27ub") when you enter it in the SETUP/OPTIONS pull down. * SPECJT WATERFALL. Some of the big changes in the new JT65 include the fact that WSJT now includes its own improved waterfall display, so that it is not necessary to watch SPECTRAN to see the weak signals. There are three sliders along the bottom of the SPECJT screen, as well as options along the top. I set mine as follows: I select OPTIONS/FREQUENCY AXIS and OPTIONS/PALETTE/LINRAD. I set the speed to 3. The BRIGHTNESS slider (at the bottom left) is set approximately in the middle of its range. The CONTRAST slider (just to the left of center at the bottom) is set slightly to the right of center. The DIGITAL GAIN slider (on the right bottom) is set so JT65 displays a level between zero and +2 dB. With the proper settings, the SPECJT screen should show some faint "yellow snow" over the 1200-1500Hz range with no signals present. * SOUND CARD CORRECTION. With the new version, it also is possible to enter sound card correction factors for the input and outgoing audio. The suggested correction factors are displayed in the lower left corner of the JT65 screen for the particular sound card being used in your computer. This is a big improvement, especially for laptop computers (whose sound cards were often not so accurate). Make sure to enter the correction values displayed, by typing them in under the SETUP/OPTIONS/ (under "Rate in" and "Rate out"). * COMPUTER CLOCK. Note that you will still have to set your computer clock accurately, although the new version allows for twice as much error in your timing. If you do not have a connection to the internet while you are on the air (so you can automatically update the computer clock using DIMENSION 4 or a similar program), or do not have a GPS unit automatically updating your computer clock, you should try to manually set it within a second or two of the correct time by listening to WWV. * WEAK CW DISPLAY. Note that you can also use the SPECJT screen while you are in the JT65 MONITOR mode to display weak CW signals. Additional notes on CW EME can be found on my web page under note #10. Note that on CW, the signals will be ZERO BEAT on the operating frequencies specified. Also, remember what contitutes a contact. One station must receive final RRR - then contact is complete. The way a contact progresses (either CW or JT65) is listed under the HELP button (or just press F5) on the JT65 screen. You must ALTERNATE the messages through the contact to efficiently make it work. First station sends calls, second station sends calls and OOO, first station sends RO, second station sends RRR. It is NOT efficient (and often not successful) if one station simply "parrots" what they have been receiving. * DECODE PULL DOWN SETTINGS. You should make sure that DECODE/JT65 is set for EXHAUSTIVE. If you have a fast computer, you don't need to check anything else under that category. Only if your computer seems to take a long time to decode (at the end of a receive sequence), you can try changing the setting to DECODE/JT65/FAST or DECODE/JT65/NORMAL. Make sure you do not have the DECODE/JT65 "AGGRESSIVE" ever checked! That will give you a high percentage of false decodes, and is only for VERY experienced users who are carefully watching the DT and DF to determine whether the decodes are real or false. * SAVE DECODED. If you have space on your computer, I would suggest always saving your decoded .wav files as documentation of your contacts. You can do this under the SAVE/DECODED button at the top (I would NOT suggest checking SAVE/ALL). * MESSAGE SELECTION. Once the XMIT sequence begins, you can't change messages #1 or #2, so make sure you decode the incoming message and select the appropriat outgoing message before your XMIT period begins! You CAN switch to the "shorthand messages" of RO, RRR and 73, if that is appropriate, anytime by pressing the little button to the right of the messages. *FALSE DECODES. If you see a weak (low sync and dB values) station calling you and there is a "?" behind the decode, it should probably be ignored as a false decode. This is quite common if signals are weak and there is QRM. If there is any such question about whether a station is really calling you or not, or they are really sending you OOO or RO or RRR, wait to see it a second time. Note that one of the ways you will be able to tell whether decodes with callsigns are "REAL" or not, is the value of DT. Assuming that the computer clocks are acccurately set on both ends of the EME circuit, the DT (the Delay Time) for the signals to go to the moon and back should read between 2.5 and 3.5 seconds. If it is something like zero or -1.0, it is probably bogus interference. *IDENTIFYING STATIONS. Often, stations will be identified by their DF (Frequency Difference from the normal sync tone frequency around 1280 Hz), and that must be closely watched. For example, if a station sends you calls and OOO and his DF is +127 Hz, the "RRR" (shorthand message without callsigns) are probably coming from him if the RRR are coming from someone at +125 Hz. If you have multiple different messages coming to you from different stations - for example someone sending RRR or RO while you are also copying calls from someone on another frequency - you can use the DF to help determine who is sending what (just like you would distinguish between CW signals by their respective pitches). * SHORTHAND MESSAGES. Remember that the "shorthand" messages (those only represented by different alternating tone frequencies) of "RO" and "RRR" will usually show a "?" mark after them if you are not copying them with a FREEZE filter turned on (and with a TOL less than 100 Hz). With the narrow TOL, you will see the ? disappear if the message is real. The rationale for this is that, since there are no calls with these messages, you are identifying who is sending these messages simply by the DF, and making sure that it is from the station (which you identify by their frequency) with whom you are in process of completing. * SYNC BOX. The SYNC box in the center of the main JT65 screen acts like a "squelch" to set the level at which the program should try to decode messages. Setting it at zero would tell the program to try to decode extremely weak messages (and/or noise bursts), which will result in a large percentage of false decodes. The SYNC setting should always be set at +1. * SKED BOX. Remember that it is OK to put a check mark in the SKED box during a sked, but if you are interested in trying to decode ANYBODY else (even a random caller while you have another callsign in the TO RADIO window) it will be virtually impossible unless they are obscenely strong. Unless you are only running a sked, and not interested in any other decodes, it is probably safest to always leave the SKED box UNCHECKED. * TX FIRST BOX. Remember, you need to always need to have the TX FIRST box either checked or unchecked, depending on how your skeds are set up. You don't want to be transmitting at the same time as everyone else, in which case nobody will ever hear anything! * ZAP BOX. You can get assistance in filtering out birdies by using the ZAP box. However, if you see no birdies with unchanging frequency on your SPECJT spectrum, I would suggest leaving this unchecked. * CLIP/NB BOX. The NB box is basically an adjustable noise blanker to work on things like static crashes. Since some sensitivity is sacrificed, it is recommended to leave the NB box unchecked unless absolutely necessary. * AFC BOX. The AFC box is a way to try to decode drifting signals. It is always best to leave your rig on and well warmed up prior to an operating period. If you see signals that appear to drift as they are displayed on the SPECJT waterfall, you can always try to DECODE again with the AFC box checked. Otherwise, I suggest leaving it unchecked. * FREEZE/TOL. Remember that the FREEZE box is basically a narrow DSP filter (the width of which is set by the TOL settings). You must have the receiver always in the wide open (widest bandwidth and XTAL) USB position, and use the FREEZE filter to select which station you want to decode. Make sure you know how to properly use the FREEZE filter to move it to different traces and decode the different stations calling you during any particular minute using the DECODE again button after you reset the FREEZE filter on a particular station. * QUICK RESETS/DECODING. If you move the mouse cursor onto the main sync frequency trace of a station shown on the SPECJT screen, and DOUBLE CLICK it, you will immediately decode that particular station (provided you have a narrow enough FREEZE filter turned on). If you double click on a decoded callsign of a station who is calling you, you will automatically set your next transmit message to TX2 (you will be sending them OOO and calls as soon as your next XMIT period begins). If you double click on the decoded callsign of a station who was calling CQ, you will automatically set your next transmitted message to TX1 (just callsigns). * CALLSIGNS WITH SHORTHAND MESSAGES. If you are working a pileup, and/or skeds with random callers, you can avoid confusion by sending calls PLUS "RO" and/or "RRR" so everyone can be clear as to whom is being worked. Of course, if you are just working people on random, and have no schedule at that time you can probably just work down through the standard messages shown on the JT65 screen (which will include just "RO" by itself and "RRR" by itself without any callsigns). Note that there currently is NO PROVISION in JT65 to automatically include the callsigns with the shorthand messages if that is desired. I have found that it is often easiest to just simply make the changes in the standard TX1 message and then select it for sending. So, if you want to add "RO" or "RRR" to your callsign messages, simply replace your grid locator in TX1 message with either "RO" or "RRR". Note that you MUST use those messages for maximum sensitivity (do NOT enter "RORO" or "RR") since JT65 is looking for standard generated messages (it is important to use these formats, as the sensitivity is much improved). For example, if 3Y0X is making a contact with W7GJ and has already decoded callsigns, they would be sending the automatically generated TX2 standard message of "W7GJ 3Y0X EC41 OOO" and would have "W7GJ 3Y0X EC41" for the message in TX1. If they see (from the traces on the SPECJT screen) an "RO" coming in from W7GJ, wanted to send "RRR" to complete the contact in the next sequence, but wanted to avoid confusion with another station who still might be running a sked with them, they would replace their locator in the TX1 message with "RRR". This creates the message "W7GJ 3Y0X RRR". Then they would select that message for sending at the beginning of your next XMIT period (by pressing the TX1 button). This is a lot to do in 8 seconds (or less) between the decode of the received period and the start of the next XMIT period, but it IS POSSIBLE with some practice and familiarity with the procedure and reading the incoming messages off the SPECJT screen. JT65 will still look for a message of that exact format (or "W7GJ 3Y0X RO"), so it is very important to follow that format. Remember that a message such as "W7GJ 3Y0X RORO" or "W7GJ 3Y0X RR" would not have any more sensitivity that the random text message of "TU NEW DXCC", which is possible if signals are VERY strong, but is NOT recommended, because such messages could waste a lot of time without decoding at all. This last option adds a level of complexity to the JT65 operation, but it can greatly increase the rate of successful random contacts. This is discussed further in section IV of my web page: http://www.bigskyspaces.com/w7gj/DXPEDITIONS.htm * RECEIVER SETTINGS. Remember to make sure that your receiver is set for the widest possible passband, with the widest possible XTAL filter for USB. There must be NO DSP filters or audio filters turned on! In addition, the AGC should be turned OFF, and the noise blanker should probably be turned ON. * WSJT MODE SETTINGS. You may laugh at this, but remember to make sure that you are running the correct mode! JT65A is the standard for 6m EME. JT65B is the standard for 2m. JT65B or JT65C are used on the higher frequencies. Especially if you operate more than one band, it is easy to forget to change the setting when you change bands! * CALL3.TXT. I have created an expanded call3.TXT file that includes all the currently active stations on EME. You can dowload it from my website, and simply copy it into the directory where you have WJST installed: http://www.bigskyspaces.com/w7gj/call3.txt
