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[Articles Home]  [Add Article]  

JT65-HF -- an 'Odd' but Fun Digital Mode

Dave Dunbar (N0RQ) on April 6, 2011
View comments about this article!

In case you’ve never seen it before, let’s explore a seemingly-little-known digital mode called JT65-HF.  In some ways, it is very similar to other digital modes such as PSK31, but it some ways, it is very much different.

 

First, the similarities.  The equipment required is the same as other digital modes, that is, the rig, the antenna, the computer with software, and a sound card interface.  None of that will be new to you if you’ve ever done digital before. 

 

It is also a low-power mode, even more so than PSK31.  On the upper HF bands, you’ll often run 5W-10W or so.  On the lower bands, 5W-10W will often do the trick, but for DX you might well crank it up to 30W-40W if really needed.  Some JT65-HF users are committed to 5W max, period.  It is important not to crank up the power too much because it will make it hard or impossible for others to hear weaker signals, just like on PSK31.  In most cases, 10W will be sufficient.  This is an extremely efficient weak-signal mode.

 

Just like PSK31, you’ll also want to watch the ALC meter on the rig to keep from overdriving the signal.  This isn’t quite as critical on JT65-HF as it is on PSK31, but it is still important.  There should be zero ALC for these modes – if you see some, turn down the sound card volume/output until ALC readings disappear.

 

OK, fine, that’s the stuff you already knew.  So what’s so different about JT65-HF?


First, your favorite software doesn’t do this mode.  It’s not in FLDIGI or HRD/DM780 or MixW or anything else like that.  You need special software.  (Have no fear, it’s free!)  There are technically two choices, though in reality there’s only one good choice for the new user.  You could use WSJT v9, which is THE choice for VHF/UHF high-speed meteor scatter (HSMS), as one of its modes is JT65A (JT65-HF), but this is not the wise choice for HF because it doesn’t help with QSO procedures on HF.  What you really want to get (trust me on this) is JT65-HF.  The current version is 1.0.7, and can be found at the link listed at the end.  Installation is pretty easy, and requires only limited configuration.

 

Second, and the thing that is most unique about JT65-HF, are the QSO procedures.  It is not a transmit-at-will or send-whatever-you-want mode.  It is highly structured (similar to FSK441 or ISCAT on VHF) and because the maximum number of characters you can send in freeform is 13 (that’s right, thirteen).  And here you thought a 140-character tweet on Twitter was short!

 

The sequence of a contact depends on the computer clock being very accurate.  We’re not talking within 30 seconds here.  2 seconds off is barely acceptable.  1 second off is usually OK.  In reality, you’ll want it to be less than 0.5 seconds off.  What that means for you is that the built-in Windows clock sync probably won’t be sufficient.  You need to get good clock sync software.  The most popular one is D4 (Dimension 4);  Meinberg is the other major choice (links below).  If you’re running Win7 or Vista, look at Meinberg first, but D4 will work if you run it as Admin and in XP compatibility mode.  Either of them will keep your clock accurate to within a few hundredths of a second.

 

So now that your clock is good, you’re ready to decode some signals.  Start the software and tune your rig to 20m (USB dial freq 14076) or 40m (USB dial freq 7076), or pick one of the other bands, but make sure to pick a standard JT65-HF freq (1838, 3576, ~10138, 18102, 21076, 24920, 28076 kHz) and make sure it is USB.  If you’re receiving a signal, it should look something like this waterfall:

 

jt65-hf-5-signals

 

This is very similar to waterfalls for other digital modes.  Across the top is the offset in Hertz – note the 2kHz width.  From top to bottom is time, most recent on top.  The thin red lines delineate minutes.  Where you see two thin red lines close to each other means I was transmitting most of that minute.  In the current minute (at the top) there is a modestly-weak signal at nearly -500Hz, and a strong one at about +40Hz.  If you go back several minutes, you might see the very weak signal at -150Hz and another at about -730Hz.  Those very weak signals could very well have been decoded.  The “sync” tones at the left of the 175Hz signal are transmitted more than the others, so they tend to show up the best.


JT65-HF is done 60 seconds at a time.  For 48 seconds, a station will transmit, and then there are 12 seconds of silence.  Then in the next minute, the other station transmits for 48 seconds, followed by (you guessed it) 12 seconds of silence.  During those 12 seconds, the computer is very busy decoding everything it can in the 2kHz segment and displaying the results in the decode window.  Near the end of the 12 seconds, the receiving station decides if he wants to answer a CQ, or proceed to the next step of an in-progress QSO.

 

OK, time for the description of how a QSO works.  I’m going to call CQ, and W1AW will decide to answer me.

 

I click on the Call CQ button and Enable TX.  At the 00 second mark (of either the even or odd minute, depending on which I chose), I will send CQ N0RQ EM13 .  (This is what is generated by the program, and as you’ll see, both grids and a signal report are exchanged.)  My xmit will last for 48 seconds, and in the following minute, I’ll wait to see if I get a response. 

W1AW sees my signal, decodes it, and decides to answer, so he’ll double-click the decoded line which will make the software start sending at the 00 second mark of the next minute.  He will send N0RQ W1AW FN31 .  When I see that and decode it, I’ll proceed to the next step (either by double-clicking on that decoded line, or by clicking on the Answer Caller button), which will make me send W1AW N0RQ -06 . “06” is the signal strength in dB, automatically filled in by the program, and will range from -01 (extremely strong) to -25 or so (extremely weak).  After that, W1AW will send N0RQ W1AW R-13 , meaning “roger, your signal is” -13 or whatever.  My response to that is W1AW N0RQ RRR , and then he’ll send N0RQ W1AW 73 (or some freeform “73”-type text), and the final step is for me to send W1AW N0RQ 73 (or perhaps something like TU HQ! 73 or 5W DIPOLE 73). 

 

To see it a bit more clearly, it would look like this:

 

CQ N0RQ EM13                                 (I CQ)

N0RQ W1AW FN31         (he answers with his grid)

W1AW N0RQ -06                             (I send signal report)

N0RQ W1AW R-13           (he sends Roger and my signal report)

W1AW N0RQ RRR                            (I acknowledge receipt of his report)

N0RQ W1AW 73               (he sends a standard or freeform 73)

10W DIPOLE 73                                 (I send a freeform or standard 73 – contact is over)

 

Key note: only proceed to the next step if you heard that the other station proceeded to his next step – otherwise, repeat the step you’re on until you hear him proceed.  The buttons in the JT65-HF software show the natural progress of a contact – the first row of buttons if you’re doing the CQ, and the second row of buttons if you’re answering a CQ.

 

That’s it in a nutshell.  When you actually see the JT65-HF screen and watch a couple of QSOs, it will make a lot more sense.  As you can see, a single contact takes 7 minutes or more.


JT65-HF is so labeled because it sends 65 tones spread out over 175Hz. The “JT” part comes from the original creator of this type of mode, Joe Taylor, K1JT, the 1993 winner of the Nobel Prize in physics, and the author of the excellent HSMS and EME software known as WSJT

 

JT65-HF is written by W6CQZ, and is an extremely efficient weak-signal mode – it is possible to decode signals you simply cannot hear in audio and can even barely see on the waterfall display.  You’ll probably love it or hate it – if you’re a ragchewer, you might hate it – but many of us have found it to be addictively fun!  Even with my modest remote station in the central US and low power, I’ve worked guys all over Europe and in other countries as well.

 

For logging, the mode in your log should say JT65 (though technically, the mode is JT65A).  A good majority of JT65-HF users are LOTW participants, making QSLing easy.  The software has a built-in logging function, which creates a standard .adif file, which can easily be imported into your favorite logging software.

 

Before concluding, it is certainly worth mentioning a very useful add-on product called JT-Alert by VK3AMA.  It is distinct from JT65-HF, but works closely with it.  It looks at the decodes made by JT65-HF and then displays info and makes sounds when it detects things like CQ, or your callsign being sent by someone (such as an answer to your CQ), or a wanted state.  It can also detect that you’ve worked someone before on the band you’re on and optionally ignore any alert that may have been generated.  It is a helpful tool that is worth installing.


Here are those links I promised:

http://sourceforge.net/projects/jt65-hf/files/  download the latest software and .pdf setup/operations doc

http://www.hamclubs.info/JT-Utilities/   JT-Alert add-on software with visual and audio alerts

http://hamspots.net/wsjt/  “cluster”-type spots for JT65-HF and other digital modes

http://groups.google.com/group/jt65-hf  JT65-HF group discussions (on Google groups)

http://www.thinkman.com/dimension4/index.htm  D4 time sync

http://www.meinberg.de/english/sw/ntp.htm  Meinberg time sync

 

Although I’ve gone into a modest level of detail with this article, there are setup options and some operating procedures that were not covered.  I highly suggest reading the excellent setup manual/documentation.  The JT65-HF group discussions are also very useful, with a great set of friendly and helpful folks participating.

 

Go forth and have fun on JT65-HF!

73, Dave NØRQ

http://www.powerlinenoise.com/n0rq/

Member Comments:
This article has expired. No more comments may be added.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by KM3K on April 6, 2011 Mail this to a friend!
Very well done. You are a good salesman; I'm going to have to try it.
BTW, the waterfall did not display on my screen.
73 Jerry KM3K
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by K9IUQ on April 6, 2011 Mail this to a friend!
I tried JT-65 a couple of years ago on 20 mtrs. After a dozen or so contacts it was about as interesting as watching grass grow. I suppose it has a purpose, I just never figured out what it was. I doubt it was ever intended to be used on the HF bands.

For lower power experimentation and propagation work WSPR (developed by JT-65's daddy) is much more fun and practical.

Stan K9IUQ
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by K0CBA on April 6, 2011 Mail this to a friend!
Must take a long time to send all of the 'MMs' (mindless micros) used on PSK.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by WY3X on April 6, 2011 Mail this to a friend!
What kind of signal report is "-06" and "R-13"? Standard signal reporting (voice) is XX and digital/CW is XXX with the first X being 1 through 5 and the other Xs being 1~9. I'm not sure these oddball exchanges are valid for awards.(?) If someone sent me a signal report like that I'd probably think that the band died during the sending of my signal report and got garbled, and I would keep asking for a re-send. -WY3X
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N5ACK on April 6, 2011 Mail this to a friend!
Agreed,very well done article. I also can't see the image on my machine. Shows as a broken image link.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by WD8OQX on April 6, 2011 Mail this to a friend!
So, I take it if one wants to run this, there computer has to be "infested" with the "REDMOND VIRUS" (M$)?
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by WN0Y on April 6, 2011 Mail this to a friend!
I just started using this mode after reading an article on it in the April QST. It is interesting and fun, although definately not a "ragchew" mode of any sort. For those of us with less than ideal antenna locations and low power, it offers a way to work DX that might not otherwise be possible. JT65 signals are reported on the PSKreporter website which makes it interesting to see where yous signal is being heard. Using this tool, it's easy to see that my range is far greater with this mode than with PSK-31, even with lower power levels. I think it is worth trying - some will like it and some will hate it - but that's part of why this is such an interesting hobby. I'm all for trying new things.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K3GAU on April 6, 2011 Mail this to a friend!
WY3X,

Technically, the "-06" is the level of the received signal in dB compared to the noise power in a 3 KHz audio bandwidth. And, anyway you cut it, it is a much more accurate signal report than the typical "Your 599 here. Could you please repeat your name / location again?" type of reports you get from, or give to, every DX or contest contact!

To tha author of the piece, besides WSJT and HF-JT, MULTIPSK also has JT-65 built in and an auxillary program called CLOCK that can be used to set the computer clock accurately. However it is not free.

Personally, using JT-65 on HF doesn't do anything for me but it is a good program for what it was originally designed to do, very weak signals on VHF and up and for moonbounce.

Dsve
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by AB0DI on April 6, 2011 Mail this to a friend!
I've been using JT65-HF since February 2 and have logged 157 QSOs with 82 confirmed on LoTW and 94 on eQSL. I usually have it running while doing other things on the computer or at my desk (like writing this comment). JT-Alert notifies me when something interesting pops up. I have a very limited antenna (G5RV at 25 feet) and live in the mid-west. I usually run 20-30W and all of my contacts have been on 20 or 40 meters.

I've logged the following DX: Asiatic Russia, Australia (4 states), Austria, Belarus, Canada, Canary Is., Croatia, Cuba, Curacao Is., Denmark, England, European Russia, Faroe Is., Finland, France, Germany, Greenland, Hawaii, Hungary, Ireland,Italy, Japan, Latvia, Luxembourg, Netherlands, New Zealand, Northern Ireland, Poland, Portugal, Reunion I., Scotland, Slovenia, South Africa, Spain, Sweden, Switzerland, and Wales.

I've also logged 30 US states.

It's a lot of fun.


73, Tom
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N4KZ on April 6, 2011 Mail this to a friend!
This mode has its place on HF. I have used WSJT in the past to work some 6m meteor scatter. When K1JT published his initial WSJT article in QST, he mentioned having worked a station on 6m meteor scatter that was using an 80 meter horizontal loop on 6m. That was me.

Back in the '90s, I did a lot of 2m meteor scatter on SSB. It took skill, luck and some fast thinking to make those QSOs. It was fun, challenging and gratifying. But the first time I used WSJT on 6m meteor scatter, I was completely bored because the computer was doing all the work. I just went along for the ride. It would have been more interesting on 2m M-S but I lacked the antennas at that time.

All that said, I think for those hams who have antenna restrictions, WSJT is a great tool for them to work the world with a modest station. Like the guy in Texas who told me once that his wife convinced him to give up their country home -- and his towers and monobanders -- to move into a nice new home in town. "PSK31 gave me my hobby back," he told me as he explained about his attic dipole. JT-65 on HF is much the same and therefore it has a following and a place on the ham bands.

But as one who is blessed to have good HF antennas these days, I find no appeal in using it. For grins these days, I run QRP and work tons of DX. That satisfies my adventuresome itch. But if I ever find myself with an attic dipole, JT-65 HF will be the first program I install on my computer.

73, Dave, N4KZ
 
Not a QSO mode.  
by WB4M on April 6, 2011 Mail this to a friend!
The QSO example in the article is a complete JT-65 "QSO", if you want to call it a QSO. You call CQ, exchange "reports" and maybe some tid-bit such as "5W dipole". It is slightly more exciting than watching paint dry or running a beacon.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by W5DPK on April 6, 2011 Mail this to a friend!
OK I know this mode is not for everyone but really what other mode has the capabilities to work the EU , South Africa, South America, Japan, New Zealand and Australia all on 40 meters, low power about 20 watts with a dipole up 25 feet on a Saturday morning between 7 am and 8:30 am.

It was a amazing example of what the mode can accomplish and a very good band opening.

I am having a lot of fun with this mode, and while using the Reverse Beacon you can watch as the bands open and close in areas all over the world. Very handy info for working DX.


Just thinking out load here.

Dennis N5DPK
Lake Hawkins TX
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by KH6DC on April 6, 2011 Mail this to a friend!
Thanks for a great article. I've been using JT65A for several months and it's a cool method using 10 watts. It took some time to figure out the QSO but the software makes it easy. I tried WSJT and JT65-HF and none work on my computer. WSJT works only once after installation but hte next time, it yields an error message with a runtime error. JT65-HF says it can't open the channel in stereo and shuts down. The only software that works for me is Multipsk, a French software.

73 Delwyn KH6DC
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by WB0FDJ on April 6, 2011 Mail this to a friend!
Excellent review for anyone who hasn't used the mode. I am hardcord QRP and this is THE mode for it. I regularly use my FT817 with 2W out and work both coasts from MN. Running my IC703 I've worked some nice DX. My first contact using Joe Taylors WSJT suite was a UA0 followed by a KH6 running 5 watts. Yeah it's slow but if you like to put DX in the log, this will do the trick. Thank and 73.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by N2ULF on April 7, 2011 Mail this to a friend!
JT65 certainly has its place on HF. I've used it with much success. For me, the best part was that I was able to work some states on 20m that I hadn't been able to in other modes. This included both elusive states like the Dakotas (which seem to have plenty of JT65 operators but I seldom hear on other modes) as well as many of the nearby states usually too close for normal 20m propagation. Would I want to use JT65 exclusively? No. Will I use it to make contacts at times and with locations unreachable with other modes? You bet.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by W2NLS on April 7, 2011 Mail this to a friend!
A very well-written article. I have been wondering about that mode. Now I know it is not for me! I simply would not enjoy that type of QSO. So, it saved me downloading, setting up and going through yet another learning curve. By the way, NOTHING meant against the mode -- if you enjoy it, by all means enjoy!
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by G0GQK on April 7, 2011 Mail this to a friend!
Its a bit like watching paint dry, but no matter, leave the rig on all night and when you get up next morning you'll find you've had a contact with Alaska, Taiwan, Vladivostok and you never knew about it ! Its the equivilant of painting by numbers !

G0GQK
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by NZ4O on April 7, 2011 Mail this to a friend!
I've been working JT65A using the JT65-HF software since April 2010. It's an astounding digital mode that allow one to work the world with low power and simple antennas.

The excellent free software allows you to work stations -30 db under the local noise level. This includes 160 meters.

It's almost like the mode creates it's own good propagation conditions.

73,
Thomas F. Giella NZ4O
Lakeland, FL, USA

 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by KX5JT on April 7, 2011 Mail this to a friend!
Everyone has an opinion, so here's my honest opinion.
**** BORING ****

John KX5JT
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by G3RCE on April 8, 2011 Mail this to a friend!
Thanks Dave

I have been considering trying this mode for ages.
Your article simplifies matters.
73 Rob G3RCE
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6VMO on April 8, 2011 Mail this to a friend!
Good article.

I have been using WSJT JT-65B for EME on 144MHz and 1296MHz for several years. EME operation does not lend itself to long winded rag chews, no matter what mode is used. Typically, only the minimal, necessary QSO info is passed between operators. This mode is perfect for VHF and above, not sure of its usefulness on HF.

To each their own…

73

John N6VMO
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by N4ST on April 8, 2011 Mail this to a friend!
Not a QSO mode and not everyone's "cup of tea", but it is amazing to make a DX contact with very low power and to see a perfectly decoded message pop up from a signal that is too weak to hear with your ears. Also pretty neat to use the Reverse Beacon to do A/B antenna measurements. I can compare antennas over DX propagation paths and know that my signal report from the other end is based on DSP calculated results, not some subjective assessment from a human operator.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by VE2DSB on April 9, 2011 Mail this to a friend!
I'm using JT65 (WSJT) since 3 years on 144, 432 and Hf band. Also making some EME with single yagi at moonrise and set.

Unbelievable what you can do with few watts in antenna's. On Hf band when you've done few good DX QSo's, the challenge decrease faster but still fun.

On 144 and 432, there little more challenging to make distance for a DX. If you need some rare grid, JT65 is the digital mode you need. For sure, all depend of yours antennas setup and power.

I am still loving CW but otherwise propagation conditions determine what best mode you'll need.

Long life to JT65.

73
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by W8BRI on April 9, 2011 Mail this to a friend!
I'm using JT65-HF and have made numerous contacts. its kinda fun but make sure your pc clock is accurate otherwise you will be placed under arrest by the JT65 cops.

Brian w8bri
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K8CXM on April 9, 2011 Mail this to a friend!
What you can do with JT65 is truly amazing. I did a CQ on 80 one evening last winter around 6:30 PM and watched the waterfall display and saw no answers. I was also listening to the white noise and heard no answering JT65 signal, but was blown away when the decode screen showed a G4 answer my CQ. He was BELOW the noise and not visible in the waterfall, but there none the less. We had a complete JT65 exchange, and he replied at the end that he was running 7 watts into a G5RV.
BTW, I think he was first at -26 DB, and ended at -27, pretty much the cutoff point at getting a decode.
I consider this one of my more memorable contacts. Maybe just England, but one I couldn't hear.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by N9DSJ on April 9, 2011 Mail this to a friend!
A few comments:

WY3X, it is a pretty standard EME/MS report. It is indicative of signal to noise ratio; a bit more informative than a "59" or "599"

K9IQU, yes Stan, it can be boring (eye of the beholder thing) but takes 1/2 the time of a WSPR transmission and aside from the rarely used WSPR QSO mode, it allows for two way communications, albeit not a "ragchew" mode.

G0GQK, obviously you are confused; there is no automatic/robot functions in JT65.

Is it the only mode I would use? Of course not, but it is exceptional for weak signal work on HF/VHF/UHF.

73,

Bill N9DSJ
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by K0RGR on April 9, 2011 Mail this to a friend!
I think it's a fun thing to do while I'm doing other things. I can have the JT-65HF running in the background, and just keep an eye on it to see if anybody answers me. I run about 2 watts to a 21 foot hunk of wire up in a tree. I get lots of reception reports from Europe and Africa.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by W1LIC on April 10, 2011 Mail this to a friend!
I'm one who has been hooked by JT65. As some of the comments prove, this mode isn't for everyone, especially those who like to ragchew. One great thing about our hobby is that there are so many different things to try and to enjoy. I've been licensed since 1967 and have enjoyed a lot of CW and some SSB over the years. The digital modes have offered me some new fun recently. I'm retired now and am having a ball. As others pointed out, one can make many contacts with a very modest station. As of this writing I have made JT65 contacts with over 300 different stations in all 50 states and 43 countries.

Don't knock it just because it may not be YOUR thing. If you like only CW, enjoy CW. If you like only SSB, enjoy it. If your ham radio activity is only 2-meter FM, enjoy it! I don't know about you, but I do this for FUN! If it wasn't fun, I'd go read a book or something!

73,

Wes W1LIC
Bangor, ME
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by VA7CPC on April 10, 2011 Mail this to a friend!
>>>
But if I ever find myself with an attic dipole, JT-65 HF will be the first program I install on my computer.
<<<

This comment tweaked my interest -- I am stuck with an attic dipole !

Thanks for the article -- it's the clearest thing I've read on JT-65-HF.

Charles
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by K7KB on April 11, 2011 Mail this to a friend!
I've been using JT65-HF for a couple of months now and do enjoy making low signal DX contacts. I only have a 43' Vertical so working the rare ones is a bit difficult at times, especially to the Indian Ocean. However, I was very pleased to work FR5ZU on Reunion with this mode. If it was on CW or SSB, I would have never had the chance.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by KM3K on April 11, 2011 Mail this to a friend!
to VE2DSB,
Please elaborate on "how much yagi" and what power-level were needed to do the job on 2-meter for EME.
73 Jerry KM3K
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by WA6MJE on April 11, 2011 Mail this to a friend!
I love JT65-HF. I set my small IC-7000 next to a small netbook computer on my kitchen table, and run coax out the door to a portable Buddipole hidden from my neighbors and crank down the power to about 20W. As simple as this might be, it performs like an SSB big gun. I read the mail all day on 20m and all night on 40m when I walk by the table going about my day. If something catches my eye, I stop, sit and work it and then move on to what I was doing. It is amazing how much DX is just sitting there calling CQ waiting for me. No pileups! Yes, you do not rag chew, but the efficiency in terms of performance and time and effort is a real plus. This is the most fun I have had in over 50 years of ham radio. I play all day and all night without noise bothering anyone, and without having to continuously sit in front of the rig turning the dial from band edge to band edge. It is a great mode.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6VMO on April 12, 2011 Mail this to a friend!
KM3K,

A quality 9 element horizontal 2 meter yagi, a preamp and a couple of hundred watts at moon rise or set is all that is needed to work larger EME stations with WSJT JT65B.


73

John
N6VMO
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by KE2IV on April 12, 2011 Mail this to a friend!
Thanks for this informative article. Very similar to the recent one in QST. I do want to try this mode at some point -- although as a "rag chewer" I'll probably remain preferable to PSK31.

I was a bit surprised by some of the negative comments here regarding such a straightforward informative article. If it's not "your thing" fine -- by why disparage what may be of interest to others?

I guess there are folks who just have to be negative about everything --- they lead sorry lives.....
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6HPX on April 12, 2011 Mail this to a friend!
I been reading about this mode for a few years and when I saw it posted on one of the digital groups decided to try it out, took several tries but found out some mistakes like adding my callsign as a DU1 which is where I operate alot. I found out good friends both in the Philippines and Tomas Hood where I was doing wrong. Didn't take long before was talking to stations in Poland with only 10 watts to 20 at times.

Its a fun mode like PSK31, which I been using for 6 yrs, and hope others give it a try.

Thanks to the inventor of this great software.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by VE2DSB on April 13, 2011 Mail this to a friend!
To KM3K

I'm using single 12 elements K1FO homebrew Yagi on 144 Mhz and 300w since 3 month. It was 160w before with Mirage brick and done lot QSo's.

Using also a single 22 elements K1FO homebrew also on 432 with only 30w. In this case I need to be heard by a big gun like PI9CAM or HB9Q with hudge dish.

http://ve2dsb.rfgain.ca/Images/12eleFO_tour02.jpg

EME is a high challenge with single yagi but JT65 give a help to make it true.

73 Dan VE2DSB FN35hs
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K9MHZ on April 13, 2011 Mail this to a friend!
My goodness, you have a nice setup, Dave!

Best,

Brad, K9MHZ

 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by W7ETA on April 17, 2011 Mail this to a friend!
Thanks for an interesting and informative article--"let’s explore a seemingly-little-known digital mode called JT65-HF"

Best from Tucson AZ
Bob
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K9MHZ on April 18, 2011 Mail this to a friend!
>>>>By WY3X on April 6, 2011... What kind of signal report is "-06" and "R-13"? Standard signal reporting (voice) is XX and digital/CW is XXX with the first X being 1 through 5 and the other Xs being 1~9.<<<<


It's a weak signal mode, so RST won't work. Those dB down values are reported against a reference point. In many cases, the operator can't even hear what he's receiving.

RS/RST has been around for many years, and it relies upon the ears of the receiving station's operator to make a qualitative assessment of what he's hearing. The T part gave a CW operator an idea of the stability of his oscillator and also the presence/absence of key clicks. Using it to describe modern digital modes is a real stretch. Other descriptions are being tried, describing splatter (overdriven or not), signal bandwidth, etc....

http://www.rsq-info.net/

Still, as JT65 is so capable at such low received signal strengths, an effective signal report is probably going to have to be equipment generated. While it might give some nay sayers something to bemoan, remember that your local repeater custodians have been using equipment to measure sub audible tones, SINAD, etc....all in guess what...dB.

JT65-HF came from JT-65, which gave EME a shot in the arm because operators can now use much more modest equipment and get good EME results, which in the past was reserved for big guns.

While boutique and not a QSO mode, it is what it is.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by KF6A on April 19, 2011 Mail this to a friend!
It is amazing how many hams are so negative about so many things.

As for what JT65 can do for you I ran some tests with a ham acquaintance in New Zealand on 80m using PSK31, JT65A and Olivia. QSO's were 100% reliable with JT65A using under 40w. QSO's were not possible using Olivia or PSK31 with 40w and there was no sign of any signal at all. With the power raised to 80w there was still nothing using PSK31 and you could tell there was an Olivia signal in there but a QSO was not possible. Switched to JT65A, turned the power down and copy was 100%.

When I was actively trying to get my 5BWAS I lost count how many QSO's were not possible at all using CW and a KW but time and again JT65A worked using less than 40w. FYI, JT65 is accepted for ARRL awards; DXCC, WAS, etc.

There is no doubt JT65A is not for everyone since it is intended as a weak signal mode, which it does better than anything else as I found out, and not as a rag chewers mode, however, to poo-poo something because it isn't your cup of tea is ignorant. The more you learn about your options the better off you will be as a RADIO amateur. This mode will open lots of opportunities to work DX for those who are antenna challenged. I thought it was really neat to work South Africa from San Francisco with 4watts on 40m using JT65. I do have a shorty 40 but the guys on the other end were just running dipoles and low power. On 80m I routinely use 5w and my Inverted-L.

I'm not a QRP guy by any stretch of the imagination but using low power and working DX with JT65A is a fun thing to do when not dealing with lids in the pileups. If you enjoy telling others the color of your underwear, how many kids you have, the amount of RAM in your computer etc., then JT65 is not for you. If you would like to work others while relaxing and kicking back then give JT65A a try, you might be surprised what it can do and how well it can do it with simple antennas and low power.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by VE3EGA on April 19, 2011 Mail this to a friend!
A really nice informative article - thank you!

I have some observations and I know you touched upon one of them! but it really needs more emphasis:

Please, please, please, people UNDERSTAND that this is a 'Weak Signal Mode' derived from VHF EME, it's not a QSO mode with the guy in the next State - although I see a lot of these type of QSO's and each to their own - but you are really missing the whole point of JT65A!

Newcomer Operators should understand the JT65 philosophy before diving in and creating havoc with us users - who have been around for a while!

The first thing to do is sync your PC's Clock - go to the JT65A Website(s) and learn some stuff about why you need to do this - you found the software, so have a read about the mode itself!

Next, find the Power Control on your radio and turn it the ##&%$# down!

Next- adjust your sound card properly - don't overdrive the input to your JT65A software (however you do this is your choice - just do it!)- goes for PSK31 too, fella!

Now, let me explain why, you DO NOT NEED anything over 20W (25W is QRO in JT65A) TX Power - Why? - well you will simply QRM the beejeezers out of everyone's receiver that is in 'listening', mode, - that is (processing signals) during the 1 minute receive phase of JT65.

Trust me, you WILL QRM others (blacken their displays)over a very large distance. Reason the software is VERY, VERY sensitive and we are also looking at a wide chunk of spectrum!

During your TX cycle, do not always expect someone to instantly reply (like in PSK31 etc) - your CQ or reply will be re-broadcast several times once you hit 'enable TX' - be patient -YOU WILL BE HEARD - JT65 is NOT a fast mode sooooo just be patient. Sometimes the other guy's software is listening to stuff you cannot hear immediately!

I have worked stations in Europe and Australia, running less than 20W by just being patient and following these simple rules - and - nothing ever showed on the waterfall during the entire QSO's - only confirmations to sent/received messages, interspaced between other QSO's - that's how good it is!

The other evening, some 'Clown' sent a '73 message' indicating he was running 70W - he just didn't get it!
everyone within 200m had a deaf receiver for the duration of his TX cycle!

Also, I get no kick out of working someone in the same (or next 2)grid-squares, why? because I know his signal is going to be very strong (-4dB?) and I am looking, like most people to work DX - that's -18 to -23dB - I reiterate - it's a 'Weak-Signal' mode - to me that's DX! - If you want local QSO's - QSY to PSK31 etc..

So don't keep calling someone down the Street, just cos you can see or hear them - unless you are only running 1W - that kinda qualifies as DX, right?

Hope these observations help and give you more of a user's insight to working JT65A and help you become a better operator.

Now go get your DXCC on JT65A lol



73
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by LA2TD on April 20, 2011 Mail this to a friend!
Tks Dave for interesting article. I have followed ur instructions and installed JT65A, and it works very nice. After 60 years of hamming I find it very challenging to still learn new modes and having fun.
I fully support all the positive views abt ur article. (By the way my first name is really Odd, quite common name in this country!)
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K9MHZ on April 21, 2011 Mail this to a friend!
EME, folks.....it's suddenly become much easier to do!

I'm in.

Cheers,

Brad, K9MHZ

 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by K8YZK on April 22, 2011 Mail this to a friend!
I have been using JT65HF for several months and enjoy it. Yes it is not a chat mode like SSB/CW/PSK etc., but to me it is more intersting then the dribble during contest where everyone is 5/9 even if you have to ask again and again for the persons call and report.

Like other modes or type of operation, if you don't like it then move on to something you do.

73
Kurt
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by K9MHZ on April 23, 2011 Mail this to a friend!
Kurt,

I think some were comparing it to other digital modes which are chat modes. FLDIGI won't include any JT65 flavor because it isn't a chat mode, and the terminal in FLDIGI is essentially set up that way.

Agree with the rest.

Best,

Brad, K9MHZ

 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by VA3PID on May 1, 2011 Mail this to a friend!
Nope, WD8OQX - it runs fine under Linux. Sounds kinda eerie as it pipes out the soundcard.
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by AD5QE on May 5, 2011 Mail this to a friend!
JT65 in all its flavors is so successful as a weak signal mode because it redefines what constitutes a valid QSO.
**RANT MODE ON**
Simply sensing the presence of a signal, under some conditions (with deep search enabled etc), can generate, what appears to the op to be a valid QSO, when in fact the only information necessarily sent over the air was the presence of a carrier wave.
All other info can be, and often is, entered into the software by the receiving station, not received over the air.
I chuckle when I hear folks say they worked 5B-DXCC in 1 year with 5W and the miraculous JT65 mode.
I use digimodes all the time, damn near daily. But when I hear some of the malarkey blowing around about miraculous contacts and such, I have to ask myself where the skeptics are, and why no one mentions the re-definition of what constitutes a valid QSO and by proxy the re-definition of DXCC, WAS, WAC, etc.
When I get my award I want it to mean something.
**RANT MODE OFF**
73 to all, Dave.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6VMO on May 6, 2011 Mail this to a friend!
JT65 in all its flavors is so successful as a weak signal mode because it redefines what constitutes a valid QSO.

-- It does redefine what constitutes a QSO. It follows exactly the long excepted practice of exchanging and verifying callsigns and a signal report by both stations.

**RANT MODE ON**
Simply sensing the presence of a signal, under some conditions (with deep search enabled etc), can generate, what appears to the op to be a valid QSO, when in fact the only information necessarily sent over the air was the presence of a carrier wave.

-- Nonsense, the software must decode up to 65 unique tones and then reports the data to the operator(s). It is still up to the operator(s) to determine if the presented data is correct.
At no time is an un-modulated carrier sent or decoded.

All other info can be, and often is, entered into the software by the receiving station, not received over the air.

-- As with any mode, operators can also be pre-disposed to DX callsigns on the reflectors and spotting networks. The operator has already made a mental or written note of the DX call and may work the DX station without ever hearing the DX station give his/her callsign. Oh, let’s not forget the accurate ‘59’ report everyone sends and receives.

I chuckle when I hear folks say they worked 5B-DXCC in 1 year with 5W and the miraculous JT65 mode.
I use digimodes all the time, damn near daily. But when I hear some of the malarkey blowing around about miraculous contacts and such, I have to ask myself where the skeptics are, and why no one mentions the re-definition of what constitutes a valid QSO and by proxy the re-definition of DXCC, WAS, WAC, etc.

-- You are not the first skeptic. These exact issues have been debated for years on the validity of JT-65 EME QSOs. It has now become an excepted and valid QSO process when followed correctly and with integrity.

When I get my award I want it to mean something.

-- If the operators follow excepted practices, a valid QSO is achieved. A QSO is only as valid as the operators initiating it. I earned the 144MHz VUCC using JT-65B on EME.

**RANT MODE OFF**
73 to all, Dave.
 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6VMO on May 6, 2011 Mail this to a friend!
My first line of reply should read:

-- It does NOT redefine what constitutes a QSO. It follows exactly the long excepted practice of exchanging and verifying callsigns and a signal report by both stations.

 
RE: JT65-HF -- an 'Odd' but Fun Digital Mode  
by KF6A on May 7, 2011 Mail this to a friend!
Dave, what are you talking about? There is no re-definition of what a QSO is with JT65, please clarify your drive-by position.

Deep search is NOT a function of JT65-HF, but since you "use digimodes all the time, damn near daily" you already knew that right? Or maybe you jumped to an ignorant conclusion and just used your drive-by hating to throw a comment without understanding what you were talking about or commenting on?

Even phone contacts are not 100% reliable so I don't know what you are tripping about. I get QSL's/eQSL's all the time from stations I never worked on CW, SSB, RTTY, etc. So much for your knowledge of what is.

Why the hate?
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by N6VL on May 7, 2011 Mail this to a friend!
I've been ham for 35 plus years now. Frankly I am talked out and don't have much to say. I like JT-65A on HF simply because I don't have to say anything, but still get the pleasure of making contacts. I even get tongue tied on keyboard digital modes like PSK31 and OLIVIA. I am able to work DX otherwise impossible with low power mediocre antennas. This mode works for at me this phase in my ham career.

Steve N6VL
 
JT65-HF -- an 'Odd' but Fun Digital Mode  
by AD5QE on May 12, 2011 Mail this to a friend!


**Rant mode OFF**

I am neither a drive by h8tr nor am I tripping. (hihi)

I would refer all to the work of Klaus DJ5HG at
the link below:

http://dubus.ns.km1708.keymachine.de/dj5hgds.pdf

Having said that, I'm prepared to eat my words in regard to the JT65-HF software published by Joe W6CQZ.

I have mentally kicked myself for ass-u-me 'ing.

As another poster stated, the deep search feature of WSJT doesn't play a role in this software's signal decoding or reception process (I'm not a programmer) and the software appears to receive all the information presented to the operator over the air. Therefore it isn't as susceptible to false decodes as the original WSJT with its DS database lookup and guess routines.

I installed and used the JT65-HF software this afternoon. I can say I'm impressed. I can clearly copy signals that were in the mud with PSK31.

I haven't tried XMIT yet, but will when I get the time sync software installed.

Some stations copied in about 4 hrs of listening:
VK4BDJ JA1PJS 2EOZRQ KH6SAT UX1LU R7BN UA3ARC OH7FMT and numerous domestic and Canadian stations.

Thanks to Joe W6CQZ for putting together a free tool for the use of the amateur community.

73 to all, Dave.

 
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