Who's palying a theremin/ 28.0750

[AlphaFive]

Does anyone have experience receiving 28.0750 NFM. It is received as a high pitched, eerie sounding CW tone that fluctuates in pitch. If you have ever heard a Theremin instrument, it has a very similar sound. I cannot locate any references to this. It is repetitive here in Asheville N.C. today, 06/03/18. I have no receiver, I am using my BCD 536, have no ability to put a bandscope on it. Thank you for your help.
PLAYING A THEREMIN...

 

[AlphaFive]

28.0750

It is on right now, 2:12 p.m. E.D.T.

 

[k7ng]

Based on the frequency you gave, it's probably JT65. There are lots of sound clips of that signal mode on the Web. Give some a listen and see if that's what you hear.

 

[AlphaFive]

28.0750

Thank you for that, I appreciate it. I'll look that up, does sound interesting...

 

[AlphaFive]

28.0750

That's it! You nailed it. Thank you, all these years, have never heard that, I Love Radio..

 

[k7ng]

Glad I could help.
There's a lot of cool sounding stuff floating around out there, and figuring out what it is, is a lot of fun.
Happy Listening!

 

[k7ng]

I should add, in NFM mode you won't hear CW/FSK signals like JT65 unless there are other signals within your IF passband to create a 'beat' tone. So you were probably actually hearing more than one JT65 signal.

If you don't want to lay out $$ for a receiver with HF capability, why not look into one of the SDR dongles that are available. Some 'starter level' dongles are available for under $100, and one that might satisfy your every dream can be found for under $200. Some go from just a few KHz to more than a GHz. They will act as scanners too, to an extent. Software may be free, or packaged with the device, or inexpensive purchase, as suits your device and requirements.

The 536 doesn't hear the best stuff on HF...

 

[AlphaFive]

28.0750

Most definitely reference the 536 and below 30 Mhz. I've got between 30 and 60 days and I will be picking up my first receiving rig. After much grinding of teeth, it will either be an Alinco DX R8, since my interest is definitely in what is below 30 Mhz. Or due to the fact that I really want to learn about receiving technology such as band scopes, waterfalls and such, I am also set on the DV1 if that is the route I decide, one of those two, won't be long. I am hanging out in the below 30 neighborhood right now as best I can to learn what is floating around, and recognize what I am hearing. I have much to learn and I can't freakin wait. Thanks for your help, I do appreciate it.

 

[ka3jjz]

SDRs are really the way to go here; the Alinco is a nice receiver, no doubt, but desktops are so 80s. There are MANY SDRs that cover HF, and we have a considerable (but undoubtedly not quite complete) listing of these in our wiki here...for that same money you can get a really good SDR...

SDRs with HF Coverage - The RadioReference Wiki

And if you're stuck inside ducking out of this pouring rain (as I am) there's a lot of links related to HF in our wiki

HF - The RadioReference Wiki

Notice the digital link? That goes into very great detail about the various modes - some readable, many are not - you will hear on HF. The appendix has lots of sites that have sound clips and/or waterfalls for numerous modes, and we have our own stored in the wiki as well

Mike

 

[AlphaFive]

HF

Ahhh, information to gleen. Rain yes, will be reading this for awhile. Thanks much, it is appreciated..

 

[GB46]

HF - The RadioReference Wiki

Notice the digital link? That goes into very great detail about the various modes - some readable, many are not - you will hear on HF. The appendix has lots of sites that have sound clips and/or waterfalls for numerous modes, and we have our own stored in the wiki as well

A very valuable resource indeed! I had been hearing what sounded like JT65 (with which I was already familiar) for quite some time, but this mode had shorter transmissions and fewer tones than JT65. The tones were also closer together in pitch. By comparison, JT65 sounds to me like random notes played on an electronic keyboard.

Anyay, I must have tried all the digital modes offered in MultiPSK, but couldn't decode any of those signals. Then I found a reference in the wiki under HF Digital Amateur Radio to FT8, which is a relatively new mode by the creator of JT65. Once I had installed the latest WSJT-X I could decode the signals very easily. In fact, there's a whole lot of FT8 activity on 7074 USB and 14074 USB. Haven't heard any JT65 for a long time.

 

[ka3jjz]

Glad that it helped you out. Just keep in mind that the ham digital wiki is just an intro, and by no means complete. The digital world is constantly changing, with new modes popping up when you least expect them. Anyone is welcome to add a mode that isn't on that page; the more we document, the more complete it will be.

We have a forum devoted to digital ham radio here...

https://forums.radioreference.com/amateur-radio-data-transmissions/

If you think the ham digital world is confusing, try keeping ahead of the digital stuff outside the ham bands. We have several references that would, quite frankly, blow your mind with all the oddball modes that have been detected See Antonio's blog for just one example...

diario SWL I5-56578 Antonio

Mike

 

[GB46]

The digital world is constantly changing, with new modes popping up when you least expect them.

So I've noticed! Designing up-to-date decoding software must be a real headache. The only reason I use MultiPSK is that it decodes so many modes. Unfortunately it can't keep up with all those changes, and the lack of FT8 is a good example. The other thing is that the program takes a very long time to launch on my machine, so that the signal often disappears by the time I'm ready to decode it. That's especially the case with ham transmissions. I no sooner get the CW mode set up and the guy stops transmitting.

It's getting so that one needs a lot of programs that specialize in only one or two modes, but my computer is kind of overpopulated with applications right now, so I'm avoiding installing even more.

We have a forum devoted to digital ham radio here...

https://forums.radioreference.com/amateur-radio-data-transmissions/

Most of that is over my head. I'm not a ham myself, just a listener. During my youth I had a technician class licence, but let it expire when I moved here to Canada in 1968 (I just dated myself again). Since then I haven't updated my limited technical knowledge. In fact, I've forgotten most of what I learned, most of it involving vacuum tube circuits. Solid state equipment was pretty new back then, and aside from RTTY, digital radio was in its infancy -- or perhaps one could say it was embryonic.

If you think the ham digital world is confusing, try keeping ahead of the digital stuff outside the ham bands. We have several references that would, quite frankly, blow your mind with all the oddball modes that have been detected See Antonio's blog for just one example...

diario SWL I5-56578 Antonio

Wow, I see what you mean, Mike!

Anyway, I seem to be wandering off topic here; sorry about that!

 

[SDRPlayer]

Antonio's site is brilliant if you are into HF data modes, his breakdown of modulation types always impresses me.

 

[RFI-EMI-GUY]

I should add, in NFM mode you won't hear CW/FSK signals like JT65 unless there are other signals within your IF passband to create a 'beat' tone. So you were probably actually hearing more than one JT65 signal.

If you don't want to lay out $$ for a receiver with HF capability, why not look into one of the SDR dongles that are available. Some 'starter level' dongles are available for under $100, and one that might satisfy your every dream can be found for under $200. Some go from just a few KHz to more than a GHz. They will act as scanners too, to an extent. Software may be free, or packaged with the device, or inexpensive purchase, as suits your device and requirements.

The 536 doesn't hear the best stuff on HF...

I don't think that being in FM mode entirely precludes receiving FSK . There will be audible frequency changes on the discriminator . I used to hear FSK from VHF navigation satellites . They were better detected in AM or SSB, but they were there.

Sent from my SM-T350 using Tapatalk

 

[mm]

Nobody uses JT65 much anymore and FT8 has taken over on all ham bands.

A swl receiver in USB MODE and a signalink usb digital interface running WSJT-X OR JTDX IN FT8 MODE is all that you need to decode FT8.

The following frequencies are used on the ham bands with your receiver set to UPPER SIDE-BAND OR DATA if supported, 1.840 MHZ, 3.573MHZ, 7.074MHZ, 10.136MHZ, 14.074MHZ, 18.100MHZ, 21.074MHZ, 24.915MHZ, 28.074MHZ, 50.313MHZ.

On 6 meter very little cw/ssb activity can be found anymore as 99% is found on 50.313 FT8 with North America to other continent spillover DX contacts handled on 50.323 and 50.303 FT8, no NORTH AMERICA TO NORTH AMERICA CONTACTS on these later 2 frequencies.

 

[K5MPH]

Glad that it helped you out. Just keep in mind that the ham digital wiki is just an intro, and by no means complete. The digital world is constantly changing, with new modes popping up when you least expect them. Anyone is welcome to add a mode that isn't on that page; the more we document, the more complete it will be.

We have a forum devoted to digital ham radio here...

https://forums.radioreference.com/amateur-radio-data-transmissions/

If you think the ham digital world is confusing, try keeping ahead of the digital stuff outside the ham bands. We have several references that would, quite frankly, blow your mind with all the oddball modes that have been detected See Antonio's blog for just one example...

diario SWL I5-56578 Antonio

Mike

Thanks Mike for the Antonio's Blog page it has a lot of info....

 

[GB46]

A swl receiver in USB MODE and a signalink usb digital interface running WSJT-X OR JTDX IN FT8 MODE is all that you need to decode FT8.

It can be even easier than that if your receiver has a line-out jack. No digital interface is necessary; just connect an audio patch cord from the line-out jack to your computer's mike input jack and decode the audio with WSJT-X. I've done that successfully with all three of my receivers, even the little Sony ICF-2002 from the 1980s.

Despite the efficiency of those data transmissions, however, I still find it comforting to hear a real human voice once in a while to remind me that so far, computers have not managed to completely take over the world and make us obsolete.

 

[ka3jjz]

GB is quite right. You really only need an interface if you're transmitting. There are some occasions where a ground loop isolator might be helpful if you have loop issues, but by and large you won't need it

As we're moving toward the HF Digital world in this discussion, I'm moving this thread to the appropriate forum. Please feel free to continue these discussions...

Mike

 

[GB46]

Tonight I've been monitoring the FT8 transmissions on 7.047 mHz, and I've never heard a frequency so busy! There are dozens of stations transmitting simuttaneously at different audio pitches. Have any of you heard the sound of a pack of howling coyotes at night? That's exactly what it sounds like: a chorus with each of the singers doing their own thing. Chaotic, but somehow very haunting.

Of course, I don't have to listen to them; I can turn down the volume, or put my headphones aside, and just watch the messages on the computer monitor instead. I'm finding this mode quite addictive, especially thanks to those grid squares that let me know where the stations are. In fact, one of them is exactly a mile away from me, with a beam on a tower atop a ten-storey high-rise building. The beam is pointed in my direction, so when he's on the air, it's bedlam here. :lol: