In Windows, go to the Control Panel, Date and Time, Internet Time tab, Change settings, click Update now. Rig Control is not required but helpful when using the internal logging methods.īefore starting any of the applications, ALWAYS sync your computer’s clock with the Internet. Choose the correct sound input/output devices. If you don’t know your grid square, check QRZ or enter your address on. In the setup, enter your call sign and grid square. WSJT-X application showing QSO with XE1SAXĪpplication setup is fairly straight forward. It’s the only program that currently implements JT9. This seems to give the most accurate signal reports. I recommend using this one for newcomers. The developer has implemented many new useful features. It’s built on the same code-base so look and feel are similar. This is the old standard but no longer in development.
It’s very reliable and I’ve only noticed one issue where free hand text doesn’t always transmit. Ham Radio Deluxe is expected to include JT65 in the very near future.
Software is available on all major platforms. JT9 is typically 2 kHz above the JT65 frequency. JT65 is the overwhelming favorite of operators. Propagation is comparable between the two modes. JT9 is extended to give more accurate signal reports with a range from -50 to +49 db. They are capped at a -1 db upper limit to keep somewhat consistent with EME reports.
Signal reports range from -1 to -30 db signal-to-noise in JT65. JT9 can have ten-times the signals but decoding of overlapping signals is much less likely to happen. The JT65 sub-band can often be seen with multiple overlapping signals and they usually decode correctly. JT9 is much better for spectrum efficiency and uses less power due to narrower bandwidth. JT65 takes up just under 180 Hz and about 16 Hz for JT9. K5ND responds with my signal report of -5 db (RST “R”eceived).ĭifferences between JT65 & JT9 are bandwidth and signal reports. I reply to K5ND with his signal report of -1 db (RST Sent). K5ND is returning my CQ from grid square EM12. In messages with two call signs, the receiving station is to the left and the transmitting station to the right. Exchange beings at 01:00 UTC and completes at 01:07. The first column is the time, second is the exchange, third is the exchange translation. The maximum message length is 13 characters with the intent of limiting the exchange to call signs and signal reports. Being such a robust protocol doesn’t leave room for long messages meaning it’s not a conversational mode. More if the message is lost or not decoded. The total exchange takes about 7 minutes. In the remaining 11.3 seconds applications decode received signals, display them on screen, and receiving stations get their message ready to transmit. Stations begin transmitting 1 second after the beginning of the minute and stop 47.7 seconds later. Transmitting happens within a one-minute window then the roles are reversed for the following minute. One minute transmit and receive sequences are utilized. The computer’s clock must be as accurate as possible and within 2 seconds of other stations. When talking about JT65 almost all information applies to JT9 as well. It’s not my intention to dive into the technicals of any mode but to give hams practical operating information. Over time, JT9 was added specifically for the LF, MF, and HF bands (“Work the World with JT65 and JT9”). This is perfect for hams that cannot have large or visible antennas. It allows stations to make contacts without high power or gain antennas. Years later it was discovered that JT65 works great on the HF bands too. Still not exactly easy but it made EME a possibility for many more hams. In 2001, K1JT came up with JT65 which allowed hams to make Earth-Moon-Earth contacts with 150 W and 11-element beam antennas. After the signal makes the 500,000 mile round trip, there wasn’t much left. The signal is reflected off the moon and received by an equally powerful station with large arrays. A signal is sent toward the moon at about 1.5 kW on VHF using large directional antenna arrays. Taylor’s passions was weak signal communications and moonbounce (EME). JT65 and JT9 began with Nobel Prize Winner Dr. But you better pay attention because it can still keep you on your toes! I call it my ADD mode because I can browse the web, watch TV, or write this article during the 7-minute exchange. Whatever you call ’em, JT65 has become one of the most popular digital modes second only to PSK.
Many have equated them to watching paint dry. My favorite digital mode has to be the “JTs” otherwise known as JT65 and JT9.
Read the rest of the series in the Digital Communications in Amateur Radio articles category. This article appeared in the The Wood County Amateur Radio Club newsletter CQ Chatter August 2016 edition.