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Amateur Radio Data Transmissions - For discussion of all modes used to send data such as APRS and packet.

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Old 02-05-2017, 1:37 PM
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Default Can you name that tune ... er ... digital mode?

Does anyone know what mode is being used in the following transmission? The center frequency seems to be 14.078 Mhz, but it gets switched slightly up and down at random (not drifting), causing steady beat tones of various pitches in either CW or USB mode. It's not RTTY, because there are perhaps five or six different tones occurring at random, and the switching is quite slow. Sometimes it sounds like a tone-deaf individual trying to play a tune on a cheap music keyboard. The transmission stops briefly as if waiting for a reply, then returns.

It's always there when the propagation is good for the 20 meter band. Later in the day, when 40 meters is good, I hear it on 7.078, as well.

When I started writing this post on Feb. 5 at 17:22 UTC the 20-meter version was audible here in Western Canada.

I had always assumed that this was a mode used by hams, until I also ran across it yesterday evening somewhere between 5.3 and 5.4 Mhz. Can't recall the exact frequency, because I tuned away from it for a few minutes, and couldn't find it again, so it must have been a very short transmission.
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Old 02-05-2017, 4:50 PM
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Probably JT-65 - Listen here and see if it matches.--> http://www.kb9ukd.com/digital/JT65A.wav


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Also.. The 60 Meter ham band covers 5330 to 5403, so you were probably hearing hams there.

Last edited by jwt873; 02-05-2017 at 4:56 PM..
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Old 02-05-2017, 5:35 PM
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Actually the 60 mb usage for hams is not in a range of frequencies, but rather channels (at least here in the US). Here's the ARRL take on the matter...

60M Channel Allocation

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Old 02-05-2017, 11:54 PM
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Quote:
Originally Posted by jwt873 View Post
Probably JT-65 - Listen here and see if it matches.--> http://www.kb9ukd.com/digital/JT65A.wav


Edit...

Also.. The 60 Meter ham band covers 5330 to 5403, so you were probably hearing hams there.
Yes, thanks, that's exactly what I've been hearing! Also, I obviously haven't kept myself up to date on the frequency allocations for amateur radio. A lot has been added since I had a U.S. ham licence back in the 1960s. I had gotten used to thinking in terms of 80, 40, 20, 15 and 10 on HF. I was on 80 meters as a novice, then on 2 meters with a technician-class ticket, working AM phone, just 18 watts with no repeaters. That licence expired in 1968, and I haven't had the inclination (or the budget) to get back into hamming.
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Old 02-25-2017, 2:48 PM
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Default Re JT65

@jwt873: Thanks again for helping me identify that transmission mode. I've finally learned to use MultiPSK, and decoded some JT65 on 20 meters (14.076 Mhz). MPSK automatically produces plain text files of entire QSOs, and this is what it logged for me on Feb. 24 at my location in BC, Canada:

<RX> JT65-A (MPSK V.4.31.3)
22:36 3 -23 9 -0249 PY2ALC WB4RA 73
22:37 7 -16 9 -0741 CQ UA0ZK QO93
22:41 2 -21 9 -0744 KD0YTE UA0ZK RR73
22:43 4 -18 9 -0744 CQ UA0ZK QO93
22:45 4 -19 9 -0740 W4CSM UA0ZK -24
22:47 10 -21 9 -0740 W4CSM UA0ZK -24
22:49 2 -21 9 -0742 WV9L UA0ZK -4
22:55 5 -25 9 -0744 VA7DGS UA0ZK RR73

This was under rather poor reception conditions. There's lots of RFI where I live, and the band wasn't in top shape, either, but my trusty old Icom R75 managed to pull through for me.
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Old 02-25-2017, 4:54 PM
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Good to hear you have MPSK working. I see you snagged Brazil and Russia.

There are a pile of digital mode that can be copied with the right software. My favorite digital mode is PSK. I was very active a year or so ago, but have let it slide temporarily. I use mostly SSB now with a sprinkling of CW and Slow Scan TV.
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Old 02-25-2017, 7:38 PM
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I don't recalling decoding a message from that Brazilian station (PY2ALC), because I probably tuned in too late. I think he was actually being replied to by WB4RA in that exchange.

So far, besides JT65, I've gotten 45-baud RTTY working nicely for ham stations as well as maritime bulletins from KPH in San Francisco.. I've also managed to read SITOR messages from WLO in Mobile, Alabama. CW works nicely if there's not too much fading. Also, I finally got the weather fax images from NMC to display quite well.

To tell you the truth, however, I prefer the human voice over all those other modes, but aside for the SSB QSOs on the ham bands (I'm not a ham myself), some maritime bulletins in USB, and oceanic aeronautical position reports, there's not a whole lot of interesting stuff to listen to on HF these days. I've been a shortwave listener since my early teens (I'm 70 now), and can remember enjoying lots of international broadcasts in English, especially when music from those different countries could be heard. Many of my favorite stations have disappeared, and have either gone over to the internet or stopped broadcasting altogether. Plus, reception of European stations is not so good here in BC. When I spent six years on the Canadian prairies, reception was a lot better from that direction. But then, solar conditions were far better, too.
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