Tag Archives: JT9

Amateur Radio, ARRL Ohio Section, Ohio Section Journal

Ohio Section Journal – The Technical Coordinator – August 2016 edition

One of the responsibilities of the Technical Coordinator in the Ohio Section is to submit something for the Section Journal. The Section Journal covers Amateur Radio related things happening in and around the ARRL Ohio Section. It is published by the Section Manager Scott – N8SY and articles are submitted by cabinet members.

Once my article is published in the Journal, I will also make it available on my site with a link to the published edition.

You can receive the Journal and other Ohio Section news by joining the mailing list Scott has setup. You do not need to be a member of the ARRL, Ohio Section, or even a ham to join the mailing list. Please sign up!

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Now without further ado…

Read the full edition at: http://n8sy2.blogspot.com/2016/08/august-edition-of-ohio-section-journal.html

THE TECHNICAL COORDINATOR
Jeff Kopcak – TC
k8jtk@arrl.net

DSCF5081 K8JTKHey Gang,

As I’m beginning this month’s article some nasty storms just ripped through Cleveland on the 11th. There were branches, trees, wires, power lines down, and road closures on the west side due to those hazards, including my QTH of Westlake. Luckily I’ve heard of no injuries. If you’re not part of the NWS Skywarn program, please consider joining as a spotter. Skywarn is a volunteer program that helps the local National Weather Service office know what’s happening on the ground and assists in warning people about dangerous weather conditions. Training typically happens in the early spring for spotters. Check with your local club or Skywarn organization.

The Republican Nation Convention went off without major incident in Cleveland. I was working from home and had the scanner on most of that week. Three major trunked radio systems were utilized: MARCS, the new MARCS-IP (Multi-Agency Radio Communications System), and GCRCN (Greater Cleveland Radio Communications Network). If you didn’t set a wildcard or use UniTrunker to watch those systems, you probably missed a lot of the event communications. There were about 12 primary talk groups on GCRCN where most of the action took place. These were previously unidentified so they were not in any lists or databases that use Radio Reference. A wildcard stops on any talk group whereas programming specific talk groups into the scanner will only stop on transmissions for those talk groups. The “old” MARCS system was shut down immediately following the convention as it was kept online largely for backup. It has been replaced by the MARCS-IP system.

This month we learned the sad news of Hara Arena’s closing. No more Hamvention at Hara Arena after 52 years. The Dayton Amateur Radio Association put into action their contingency plans. It was announced that Hamvention will still be in the Dayton area. The new location is The Greene County Fair and Expo Center located in Xenia, Ohio. Michael Kalter and Ron Cramer talked about the new location on Ham Nation for about 30 minutes in episode 259. Couple of links worth visiting:

-Why we are saddened by the loss of the Hara Arena: http://ad8bc.com/bc/?p=601
-Hamvention Announces Venue for 2017: http://hamvention.org/hamvention-announces-venue-for-2017/
-Ham Nation episode 259: https://twit.tv/shows/ham-nation/episodes/259, or YouTube link: https://www.youtube.com/watch?v=g_OaKmllEDY

One of our Technical Specialists, David KD8TWG, has been involved with setting up a DMR repeater in Cleveland. The frequency is 442.0875 (+5 MHz standard offset) using Color Code 1. The repeater is connected to the K4USD cBridge (http://www.k4usd.org/). On that website is a listing of the “standard DMR Logo configuration” for repeaters connected to the bridge. Right now, your code plug should follow the layout listed on the site. A cBridge is a feature that allows interconnecting of repeaters over the Internet and a Color Code is equivalent to a PL tone or DCS on analog repeaters.

When I picked up my DMR radio at Dayton, I found a code plug that had repeaters in Dayton and Columbus for the drive home. It was a nice opportunity to quickly get on the air with DMR but I kept threating myself to write my own. With the installation of the repeater in Cleveland, I took the opportunity to do just that. What is a “code plug?” Some history I found online notes the origins came from wire plugs, later jumpers, which were plugged into the radio to enable certain options or features. Since everything is now processor based, the term continues to stick with the radio world and is a fancy word for ‘radio configuration.’ It contains transmit/receive frequencies, tone selections, timeout values, IDs, configuration settings, etc. I used the one I found in Dayton as a reference. Tytera MD-380 There is also a sample one on K4USD’s site for my radio. I compared the two and designed mine the way I thought worked best. Just because someone designed a code plug one way doesn’t mean you can’t modify or do it differently. It’s analogous to one ham’s memory channels are not the same as another. In the end, it took about 3 hours to make mine! Keep in mind that was a lot of learning and comparing, in addition I programmed all 65 possible talk groups so I don’t have to add them in later. From discussions on the air indications are it took others a few hours as well. But my code plug works! I couldn’t be happier. Well OK I could, apparently I’m just far enough away that my 5 watts doesn’t quite make the trip. I took the radio to work and tested it from there.

I am writing an introductory series for the Wood County Amateur Radio Club on getting started in digital modes. The first few articles were for those who have never worked digital and want to upgrade their station. Remaining articles will focus on a specific mode. I’ve completed 3 so far (starting in February): an introduction, station setup, and working JT65/9. Published versions can be found at the club’s website WSJT-X Conversation in the CQ Chatter newsletter: http://wcarc.bgsu.edu/. As I point out in the second article, Technician class licensees can still participate. All of these sound card digital modes can be operated over FM simplex or even a net on a repeater using an HT! There are clear downsides like not being able to transmit as far as an HF station and occupying the full 10 to 15 kHz FM, even though the bandwidth of the audio generated by the computer is less. Yes, this defeats the purpose of narrow bandwidth modes. Someone wanting to learn and experiment with these modes may get bitten by the bug and lead to a license upgrade. That’s how I did it. I plan to write an article every 2-3 months.

My dad and I had the opportunity to join the Toledo Mobile Radio Association (TMRA) on August 10. They had Chris Wilson N0CSW, National Sales Manager for Yaesu talk about their System Fusion. Chris did make it clear that the company was paying for travel so there would be some ‘sales pitches.’ The presentation was short but the program ended up being driven by the audience with a lengthy question and answer session. Some things I learned: the DR-2X Yaesu DR-2Xrepeater announced at Dayton is not going to be a replacement for the DR-1X, though they may have improved on some shortcomings. The 2X is more of a full featured repeater. It will have the ability to operate dual receive and dual transmit (but not at the same time) creating two repeaters from one unit. They are including voice messaging (like club meeting announcements). Mailboxes were users can record messages for others. This reminds me of the mailboxes repeaters used to have when autopatches were more prevalent. The 2X can monitor a separate control channel for commands. This repeater will not support WiresX but will have “MSRL” (Multi-Site Repeater Linking) via an add-on Ethernet port. Their linking technology will allow the repeater to be linked over any IP based network, including mesh. This brought to mind an interesting use-case where multiple low profile/portable repeaters could be linked at sites with mesh such as air ports, hospitals, and Red Cross shelters. This would create a linked repeater system where not as many users would have to setup cross-banding or run to the other end of a hospital to reach a radio. In contrast, something similar can be done using the AllStar Linking system. At the meeting there was alot of: “I would like this feature/I don’t like this feature in the radio,” “we’re having this problem setting up the repeater to do X” kind of Q&A. My take away from that, their plan is to add features to radios by firmware update and not always release new radios.

In addition to all the work David KD8TWG has been doing to get DMR up and running in Cleveland, he’s been helping repair and upgrade analog repeaters, and setting up APRS IGates around town. He will be giving a presentation on APRS at the Lake Erie Amateur Radio Association’s club meeting on August 30th. Dinner starts at 6:30pm with the meeting at 7:30, don’t need to have dinner to attend the presentation. Haven’t seen an official announcement on location yet but it’s expected to be at the Play Arcade in Mayfield Hts (5900 Mayfield Rd, Mayfield Heights, OH). Check the LEARA website for updates and for dinner reservations: http://www.leara.org/.

Raspberry Pi 3I will be giving my introductory Raspberry Pi presentation at the Cuyahoga Amateur Radio Society meeting, September 13 at 7:30pm. It will be updated as there is new hardware and innovations available. Their meeting location is the Busch Funeral Home, 7501 Ridge Rd, Parma, Ohio. More: http://www.2cars.org/.

Thanks for reading and 73… de Jeff – K8JTK

Amateur Radio, Digital Communications in Amateur Radio articles

Digital Communications in Amateur Radio: JT65 and JT9

This article appeared in the The Wood County Amateur Radio Club newsletter CQ Chatter August 2016 edition.

Read the rest of the series in the Digital Communications in Amateur Radio articles category.

My favorite digital mode has to be the “JTs” otherwise known as JT65 and JT9. Many have equated them to watching paint dry. Others call it the musical mode. I call it my ADD mode. Whatever you call ’em, JT65 has become one of the most popular digital modes second only to PSK. I call it my ADD mode because I can browse the web, watch TV, or write this article during the 7-minute exchange. But you better pay attention because it can still keep you on your toes!

JT65 and JT9 began with Nobel Prize Winner Dr. Joe Taylor – K1JT. One of Dr. Taylor’s passions was weak signal communications and moonbounce (EME). A signal is sent toward the moon at about 1.5 kW on VHF using large directional antenna arrays. The signal is reflected off the moon and received by an equally powerful station with large arrays. After the signal makes the 500,000 mile round trip, there wasn’t much left. CW was the only effective mode. In 2001, K1JT came up with JT65 which allowed hams to make Earth-Moon-Earth contacts with 150 W and 11-element beam antennas. Still not exactly easy but it made EME a possibility for many more hams. Years later it was discovered that JT65 works great on the HF bands too. It allows stations to make contacts without high power or gain antennas. This is perfect for hams that cannot have large or visible antennas. Over time, JT9 was added specifically for the LF, MF, and HF bands (“Work the World with JT65 and JT9”).

It’s not my intention to dive into the technicals of any mode but to give hams practical operating information. When talking about JT65 almost all information applies to JT9 as well. Both are highly time-synchronized. The computer’s clock must be as accurate as possible and within 2 seconds of other stations. One minute transmit and receive sequences are utilized. Transmitting happens within a one-minute window then the roles are reversed for the following minute. Stations begin transmitting 1 second after the beginning of the minute and stop 47.7 seconds later. In the remaining 11.3 seconds applications decode received signals, display them on screen, and receiving stations get their message ready to transmit. The total exchange takes about 7 minutes. More if the message is lost or not decoded. Being such a robust protocol doesn’t leave room for long messages meaning it’s not a conversational mode. The maximum message length is 13 characters with the intent of limiting the exchange to call signs and signal reports. Below is an actual exchange. The first column is the time, second is the exchange, third is the exchange translation. Exchange beings at 01:00 UTC and completes at 01:07. In messages with two call signs, the receiving station is to the left and the transmitting station to the right.

0100 CQ K8JTK EN91
I’m calling CQ from grid square EN91.

0101 K8JTK K5ND EM12
K5ND is returning my CQ from grid square EM12.

0102 K5ND K8JTK -01
I reply to K5ND with his signal report of -1 db (RST Sent).

0103 K8JTK K5ND R-05
K5ND responds with my signal report of -5 db (RST “R”eceived).

0104 K5ND K8JTK RRR
I respond with “roger-roger-roger.”

0105 K8JTK K5ND 73
K5ND responds with best wishes.

0106 K5ND K8JTK 73
I respond with best wishes.

Differences between JT65 & JT9 are bandwidth and signal reports. JT65 takes up just under 180 Hz and about 16 Hz for JT9. JT9 is much better for spectrum efficiency and uses less power due to narrower bandwidth. The JT65 sub-band can often be seen with multiple overlapping signals and they usually decode correctly. JT9 can have ten-times the signals but decoding of overlapping signals is much less likely to happen. Signal reports range from -1 to -30 db signal-to-noise in JT65. The lowest I’ve seen is -27. They are capped at a -1 db upper limit to keep somewhat consistent with EME reports. JT9 is extended to give more accurate signal reports with a range from -50 to +49 db. The limits I’ve seen are -27 and +15. Propagation is comparable between the two modes. JT65 is the overwhelming favorite of operators.

JT65 & JT9 have their own sub-bands. Below is a listing of those frequencies. JT9 is typically 2 kHz above the JT65 frequency. USB is the mode regardless of band.

JT65 JT9
1838 1838
3576 3578
7076 7078
10138 10140
14076 14078
18102 18104
21076 21078
24917 24919
28076 28078
50276 50278

Software is available on all major platforms. Ham Radio Deluxe is expected to include JT65 in the very near future.

Windows:
JT65-HF (http://jt65-hf.sourceforge.net/). It’s very reliable and I’ve only noticed one issue where free hand text doesn’t always transmit. This is the old standard but no longer in development.

JT65-HF-HB9HQX-Edition (http://jt65hfhb9hqxedi.sourceforge.net/). This is the replacement for the above. It’s built on the same code-base so look and feel are similar. The developer has implemented many new useful features. I recommend using this one for newcomers.

Windows/Mac/Linux:
WSJT-X (http://physics.princeton.edu/pulsar/k1jt/wsjtx.html). Software released by K1JT. This seems to give the most accurate signal reports. It’s the only program that currently implements JT9. WSJT-X is the program that I use.

WSJT-X Conversation
WSJT-X application showing QSO with XE1SAX

Application setup is fairly straight forward. In the setup, enter your call sign and grid square. If you don’t know your grid square, check QRZ or enter your address on: http://www.levinecentral.com/ham/grid_square.php. Choose the correct sound input/output devices. Configure Rig Control/PTT if needed. Rig Control is not required but helpful when using the internal logging methods.

Before starting any of the applications, ALWAYS sync your computer’s clock with the Internet. In Windows, go to the Control Panel, Date and Time, Internet Time tab, Change settings, click Update now. Most Linux distributions need to invoke ‘ntpdate.’ One feature of the HB9HQX version is automatic time syncing every 15 minutes.

All programs have the same general layout and operate in the same manner. They have a waterfall showing signals received and display markers indicating active transmit and receive windows. These can be moved by clicking on the waterfall.

Conversational buttons and boxes are often labeled Calling CQ and Answering CQ. These buttons automatically generate text during the conversation (following the standard exchange format). Free Text/Message is for free hand text. Other buttons will enable and disable transmitting. Halt will interrupt the transmission midway through. Even/odd indicates which minute you will transmit (only applies to calling CQ). It has no effect when answering a CQ because the software will transmit in the next minute.

The Signal Decoding window is the most important because this is where all conversation exchanges are displayed. A couple labels are seen: UTC – time the signal was decoded, Sync – measurement of the sync signal — higher the better, DT – time difference between decoded station and yours — should be less than 2 seconds, DF – frequency deviation above or below the center point in Hz, and finally the Exchange or Message text. Colors are frequently used to distinguish items of importance. Green is a station calling CQ, red is a message/exchange intended for your station (contains your call sign), gray is exchanges between other stations.

Luckily the software takes care of much of the exchange. It generates response messages by double-clicking a received line. Stations that don’t follow the standard format can easily confuse the software. This is where it will keep you on your toes. If you’re not careful you can end up sending a message twice or not properly advancing to the next message in the exchange. The software does not automatically advance the conversation for you. If things go off the rails, use the appropriate conversational button to get things back on track.

The Free Text field can be used for noting your power, antenna, or sending holiday greetings. These messages are often in place of the 73’s and will not show up in red because no call signs are included. You may see “30W DPL” (I’m running 30 watts into a di-pole antenna), “50W LOOP” (I’m running 50 watts into a loop antenna), “THX 4 NM” (we’ve worked before, thanks for the contact using a new mode from previous contacts), “THX 4NB” (we’ve worked before, thanks for the contact on a new band), “SRY/SRI NO DECODE” (I see a signal on the waterfall but it did not decode) you’ll see this one but it’s not commonly used, “MERRY XMAS” –you get the idea. It’s only 13 characters. Be careful not to baffle the user and you have to be quick. There are some I’ve received that I still have no idea what they mean.

In the JT’s it’s ether a clean decode or nothing at all. No in between. When I see a signal on the waterfall and the message doesn’t decode, I always send my last message again. Some stations will not transmit in the following minute. Other stations (wrongly) move on in the conversation. Then I have to use free hand text to send “SIG RPT?” or similar because I didn’t receive my signal report. At minimum, I make sure RSTs (reliability – strength – tone) have been exchanged and won’t log the contact until “RRR” has been sent/received. Some QSLs I received go as far to log the DF frequency. I’ve only logged the center frequency.

After you feel comfortable monitoring activity, double-click a green “CQ.” The Generated Text field will update with your call sign, their call sign, and your grid square. You’re off! Also, refer back to article two for station/DSP/audio setup. I’ve seen some of the worst over modulated signals on JT65. JT users are really good about uploading spots to PSK Reporter (https://www.pskreporter.info/pskmap.html). You can use it as a ‘reverse beacon’ network to see where your signal is propagating.

PSK Reporter Spots
PSK Reporter application showing received stations worldwide

It’s a lot to take in but an extremely fun mode to work. Find out more information:

Amateur Logic.TV on JT65: https://youtu.be/L7e5NbqhbVU?t=28m10s

QST article: http://www.arrl.org/files/file/Get%20on%20the%20Air%20with%20HF%20Digital/FORD%20JT.pdf

PowerPoint introduction: http://www.arrl.org/files/file/Get%20on%20the%20Air%20with%20HF%20Digital/Getting%20Started%20with%20JT65%20on%20the%20HF%20Bands.pps

“Work the World with JT65 and JT9” book: http://www.arrl.org/shop/Work-the-World-with-JT65-and-JT9/