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Author Topic: JT65-HF for dummies?  (Read 5615 times)
WALTERB
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Posts: 528




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« on: May 17, 2011, 05:48:30 PM »

Hi,
I have never heard of JT65-HF until today.  I downloaded the freeware, set it up,  got it configured (I believe) to receive. 
I’m getting green and grey packets of data, but I must be missing something.  The packets look like “Header” lists including Callsigns, and a few other item but I can’t seem to locate the “guts” of the message.   I assume there is more to it than just the cryptic headers?  Huh
Thanks.
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VA7CPC
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Posts: 2391




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« Reply #1 on: May 17, 2011, 08:59:34 PM »

JT65 is a _very_ specialized mode.  There's no "conversation", nothing to say except:

. . . A:  I heard you!

. . . B:  I heard you, too!  Goodbye . . .

So what you're seeing may be all there is.  I've never used the mode myself, I guess I should try it out.

              Charles
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WALTERB
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Posts: 528




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« Reply #2 on: May 17, 2011, 09:04:03 PM »

JT65 is a _very_ specialized mode.  There's no "conversation", nothing to say except:

. . . A:  I heard you!

. . . B:  I heard you, too!  Goodbye . . .

So what you're seeing may be all there is.  I've never used the mode myself, I guess I should try it out.

              Charles

Ok,  I don't know if that is limited just to JT65 or Just to digital either for that matter.   Grin

Glad to see I had it working correctly. 

Whats the best Long Haul Digital (besides CW)? 

thanks
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W8JX
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Posts: 6030




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« Reply #3 on: May 17, 2011, 09:25:37 PM »


Whats the best Long Haul Digital (besides CW)? 


MFSK, Pactor and Domino EX are top contenders here. They all use a form of FEC (Forward Error Correction) and will print 100% when other modes fail. Pactor will not print without a correct CRC sum and will retry until it gets it. (this is possible because receiver must acknowledge transmitter of proper CRC to move to next packet) Domino EX is very nice in that tuning/zero beating is not critical at all while other two are not very forgiving.  I once worked a station 1100 miles away with Pactor while running less than 200 milliwatts. PSK while popular cannot compete with these modes in weak signal work or under poor conditions.
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WALTERB
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Posts: 528




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« Reply #4 on: May 18, 2011, 10:44:55 AM »


Whats the best Long Haul Digital (besides CW)? 


MFSK, Pactor and Domino EX are top contenders here. They all use a form of FEC (Forward Error Correction) and will print 100% when other modes fail. Pactor will not print without a correct CRC sum and will retry until it gets it. (this is possible because receiver must acknowledge transmitter of proper CRC to move to next packet) Domino EX is very nice in that tuning/zero beating is not critical at all while other two are not very forgiving.  I once worked a station 1100 miles away with Pactor while running less than 200 milliwatts. PSK while popular cannot compete with these modes in weak signal work or under poor conditions.

Now another dumb question. How do you know which mode is being used other than just picking different modes on the software until the gobbledygook becomes Intelligible?
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AG6WT
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« Reply #5 on: May 18, 2011, 10:55:49 AM »

Now another dumb question. How do you know which mode is being used other than just picking different modes on the software until the gobbledygook becomes Intelligible?

For the most part, the different modes have a very distinctive sound and appearance. Take a look at this site for pictures and sound files of many different digital modes:

http://www.nonstopsystems.com/radio/radio-sounds.html

You can find other guides with your favorite search engine and on YouTube.
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WALTERB
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Posts: 528




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« Reply #6 on: May 18, 2011, 11:30:46 AM »

Now another dumb question. How do you know which mode is being used other than just picking different modes on the software until the gobbledygook becomes Intelligible?

For the most part, the different modes have a very distinctive sound and appearance. Take a look at this site for pictures and sound files of many different digital modes:

http://www.nonstopsystems.com/radio/radio-sounds.html

You can find other guides with your favorite search engine and on YouTube.

ok, thanks!
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VA7CPC
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« Reply #7 on: May 18, 2011, 02:44:29 PM »

While it's not the "best long-haul digital mode", PSK31 is the most-used digital mode, and it _is_ conversational -- people chat, keyboard-to-keyboard.  Set your receiver  to 14.070 USB, and you'll usually hear signals. 

The easiest software to use for PSK31 is Digipan (free).  "fldigi" is another good choice -- it's "multi-mode", and will decode most common signals.

If you check the ARRL website's "Contest Calendar", you'll find some RTTY contests.  RTTY is an old mode, but contesters like it.  "fldigi" (and most other software) will handle it.

Neither PSK31 nor RTTY uses error-correcting techniques.  If you need an _error-free_ long-haul mode, PACTOR (I, II, or III) is your best bet.

If you're getting into digital modes, it's time to study for the ham license exam.<g>  They're much more fun when you can transmit as well as listen.

                 Charles
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WALTERB
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« Reply #8 on: May 18, 2011, 05:55:53 PM »

While it's not the "best long-haul digital mode", PSK31 is the most-used digital mode, and it _is_ conversational -- people chat, keyboard-to-keyboard.  Set your receiver  to 14.070 USB, and you'll usually hear signals. 

The easiest software to use for PSK31 is Digipan (free).  "fldigi" is another good choice -- it's "multi-mode", and will decode most common signals.

If you check the ARRL website's "Contest Calendar", you'll find some RTTY contests.  RTTY is an old mode, but contesters like it.  "fldigi" (and most other software) will handle it.

Neither PSK31 nor RTTY uses error-correcting techniques.  If you need an _error-free_ long-haul mode, PACTOR (I, II, or III) is your best bet.

If you're getting into digital modes, it's time to study for the ham license exam.<g>  They're much more fun when you can transmit as well as listen.

                 Charles



Thanks.  I got my General earlier this month.  I was just trying to figure out if it was something I wanted to spend time doing.

thanks
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W8JX
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« Reply #9 on: May 19, 2011, 08:55:21 AM »


Neither PSK31 nor RTTY uses error-correcting techniques.  If you need an _error-free_ long-haul mode, PACTOR (I, II, or III) is your best bet.


While this is indeed true about PSK and RTTY, Pactor is not only solution or best. MFSK 16 is very robust and MFSK 8 even more so but slower. Dominio EX has FEC and several bandwidths and data rates and is very robust and nicest thing about domino is tuning is not critical and drift is not a concern at all as Domino listens to frequency shifts between tones not to shifts between it and base line reference frequency. Even Olivia has a FEC mode if your software supports it. I must stress you need good software to support many modes and sort them out too. MultiPSK is best software I have found for this so far and it supports pretty much everything and more than HRD or Mix32
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VA7CPC
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Posts: 2391




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« Reply #10 on: May 19, 2011, 09:07:21 PM »

Add one more FEC mode:

. . . WINMOR

It has been developed as a substitute for PACTOR-II / PACTOR-III.  It's not as fast as P-III, but it may rival Pactor-II.  Best of all, it lets you get into the WinLink 2000 e-mail network.  It's "adaptive" -- figures out the best encoding to use, based on S/N ratio and other things.


There's a keyboard-to-keyboard mode, as well as client/host mode.  See:

http://groups.yahoo.com/group/WINMOR

for more info.

              Charles

PS -- I didn't realize that Domino EX has FEC.  I've tried it (without FEC), and think it gives a good balance between speed, bandwidth, and weak-signal capability. 
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KC2UGV
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Posts: 441




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« Reply #11 on: May 20, 2011, 07:27:31 AM »

Now another dumb question. How do you know which mode is being used other than just picking different modes on the software until the gobbledygook becomes Intelligible?

Turn on RSID.  It will allow the software to listen for the signal-type ID, and turn on the correct softmodem Smiley

PSK31 users don't use it much (PSK31 being easy to spot).  Many other digimode users do Smiley
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G0GQK
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Posts: 634




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« Reply #12 on: May 22, 2011, 01:58:24 PM »

Its one of the modes for new hams where you can make contacts over a long distance and tell 'em your locator square, its a sort of hi and bye mode for those who like new squares. Think yourself lucky you get it to receive, I can't, but I can transmit !

G0GQK
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KE3WH
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« Reply #13 on: May 25, 2011, 05:14:43 PM »

Just made my first QSO's with this mode today. At least one I had no audio copy at all, minimal info on the waterfall.
Can even do other things while using it, as its really semi automated.

Dan
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First ticket 1980. Ex KA3EWT, N3DSO.
KE3WH
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« Reply #14 on: May 27, 2011, 05:33:40 PM »

Think yourself lucky you get it to receive, I can't, but I can transmit !

G0GQK
Initially I had an issue with this. I can see the signals in the waterfall, but no data. I needed to just reset the audio input to the specific port that was in use.

Dan
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First ticket 1980. Ex KA3EWT, N3DSO.
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