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HF Mystery Signals / Re: LINK- not 11?
« on: Today at 02:33 »
That is still Link-11.  In this case it is Link-11 CLEW on 6942 kHz USB.

There are two kinds of Link-11, Link-11 CLEW and Link-11 SLEW, and they do sound different from each other.  In addition to the two types, Link-11 can be variable in sound, it is not always the same.  This variability depends on several things, for example how many nodes are in the network, and what part of the network you are hearing.

For Link-11 CLEW (the kind in your picture and audio example) the bursts themselves always contain certain aspects that are unchanging.  When properly tuned (6942 kHz USB in this case) there are three major portions of the signal that can help in IDing.  There is the Doppler Tone, which will be at 605 Hz audio, there is the Synchronization pulse, which will be at 2915 Hz audio, and there 14 channels of data between those.

Link-11 SLEW is somewhat similar in pulsing nature, but a totally different structure and sound.


Spy Numbers / Re: Numbers station 11635 AM 1837 UTC
« on: January 12, 2021, 2248 UTC »
It should be groups of 5 digits in Spanish, female, with data between to be the Cuban HM01.  Is it possible you misheard the digits?


HF Beacons / Re: New Dasher 4097.22 KHz ?
« on: January 07, 2021, 1605 UTC »
I am thinking the name should probably be able to tie the 4097.2 and the 7997.2 together if it turns out they are actually related.  If I ever get them simultaneously at a good enough signal strength I will try to do a video that shows the relationship / sync of the two.  I am sure they are in sync.  Unfortunately I typically see only one at a time, and when I do see both either one or both are so weak that it does not make for a good video.


HF Beacons / Re: Currently Active Beacons Chat
« on: January 04, 2021, 1648 UTC »
First pass has been completed. I'll bet there are a lot more that have not been heard in a while such as these

7000.0 "Itchy" Ditter, 0.21 seconds long, sent every 1.39 seconds.

7000.65 "Stumpy" Ditter, about 0.17 seconds long, sent every 22 seconds.

7039.4 "T" beacon  OK0EPB sends a marker each second, a longer one at the minute, and callsign.

7998.3 "Shorty" sends 18 dashes starting every minute.

8009.7 "Hiker", Dit rate is 100 per min.

13562.90 kHz "RR-dash" beacon is located in the northern Mojave Desert of Calif. with approx. 10 mW to an inverted-L antenna.

Yeah, 7000.0 kHz Itchy appears long gone.  When it was active I could receive it anytime I looked for it, I have not seen it in a couple of years.

I strongly suspect both 2008.4 kHz dasher and 2018.3 kHz dasher are also gone, when they were active I could normally see them any morning, pre local dawn, if I went looking for them.  That was for a couple of years, but it has been a long time since I saw them, and I have been looking.  So I am pretty sure they are gone.


HF Mystery Signals / Re: Unident Signal 10.152 MHZ- Any Idea?
« on: January 03, 2021, 1807 UTC »
The thing to remember about the candidate radars, and most HF radars that change frequency at all, is that they have no set frequencies they use.  Most of them can move to any frequency they need, when they need it.  They often have frequency ranges they won't touch, but that is probably more of a black list kind of thing.  They often stay out of broadcast bands, away from aero freqs, and generally outside of ham bands (some radars, such as the Russian 29B6 and the Chinese OTHR-SW are notorious for hammering ham bands).

Changing frequency is part of how HF radars control what part of the earths surface they are watching.  They leverage current, and changing, propagation conditions to get the right skip path to the region they are interested in.  So they go to the frequency necessary when necessary, to get the job done.


Spy Numbers / Re: Numbers station
« on: January 03, 2021, 1752 UTC »
You might want to include a description of the numbers station, so we can tell which one you mean.

Right now (1745 UTC, the same day) I have the Cuban station HM01 (alternating Spanish numbers and digital data) on 11530 kHz in AM mode. But nothing unusual about that, it is one of its scheduled frequencies and times.  HM01 carrier turned off at 1750:55 UTC and it will be going to 11635 kHz for its next transmission, starting at about 1800 UTC (normally starts several minutes early).


HF Beacons / Re: Currently Active Beacons Chat
« on: January 03, 2021, 1727 UTC »
Should we pencil in the 4097.2 Dasher (possibly the former Inyo Whooper) and  the new 4095.7 Desert Whooper beacons into the master list?

Guesses on my part for both of them as of early January 2021.

4097.2x has been active since at least early November with no real changes noted since then, so it appears to be here to stay.  I don't think that is related to the old Inyo Whooper though, it does appear to be related to 7997.2 kHz.  The two dashers appear in sync.  Both of them have some interesting propagation to me on my local receivers, at times they boom in, but most of the time they are not detectable.  Typically when I can hear one I cannot hear the other, but I suspect that is propagation, as occasionally I do hear them both at the same time.

The Desert Whooper also appears to be hanging in there.  But since it is still changing a little I suspect we are not seeing it  in its final version / location yet.

My vote would be that both need to be on the lsit.


HF Beacons / Re: NYrs ditter/Dasher/whooper
« on: January 03, 2021, 1650 UTC »
Via KFS Kiwi...note that fine ditter signal !

Looks like, left to right, Desert Whooper, Marin Dit, and the as yet unnamed 15 Hz / 2 sec on/off, 4097.2 dasher.

It has been a while since I have seen the Marin Dit here at the house.

I did no beacon recordings New Years, all the recorders were busy on other things.


HF Mystery Signals / Re: Unident Signal 10.152 MHZ- Any Idea?
« on: January 03, 2021, 1636 UTC »
That is a radar.  Since it is FMCW, varying rep rate, and has what looks like a single pulse pilot tone or pre-beep it is quite possibly JORN out of Australia.  However, that is not certain.  The US ROTHR can operate with a single pulse pre-beep and look rather like this image, and there is also a Chinese radar that can use a very similar mode.

Most probably JORN, second guess US ROTHR, possibly Chinese.

The Signal Wiki page is a good starting point, but it is far from a complete reference, however, both JORN and US ROTHR should be there.


HF Mystery Signals / Re: 6505 kHz digital signal - mixed modes
« on: December 31, 2020, 1313 UTC »
Yes, that is the Saab Grintek MHF-50 modem you are hearing.  Yes it is used by the South African Navy.  Yes it can be hear din the US, I can even hear it here on the west coast.  The 6504 kHz USB channel has been RFDFed and TDOA geolocated to South Africa.  You can often find it on 3 or 4 frequencies simultaneously, for example when you hear it on 6504 kHz USB also check 8580 kHz, 12982 kHz, and 16986 kHz.


HF Beacons / Re: New dasher beacon at 7999.10?
« on: December 29, 2020, 1459 UTC »
Dasher doing fine here this afternoon and it appears a new ditter is being heard as well right next to the dasher.

7999.140 ditter
7999.212 dasher

those are the freq's that I measure them to.

73, Mark

So this 7999.212 kHz dasher is not the same one as the 7997.2 kHz dasher?

The 7997.2 kHz dasher appears to be a 2 second on, 2 second off, dash, reasonably stable in timing although some variation in frequency has been reported.  I guess we need to figure out if the 7999.212 kHz dasher is a different animal or the same one (as 7997.2 kHz) on a different freq.

Unfortunately the 7997.2 kHz dasher is a rare critter here at the house.  Maybe once a week I see it for a few minutes, always very weak.  It appears very similar / identical to the 4097.2 kHz dasher, which also is not seen often here, but somewhat more often than the 7997.2 dasher.


The Woodpecker also moved around in frequency, just not as fast as some of todays OTHRS might.  And the Woodpecker used multiple frequencies in sets, as many of todays radars do.  A big difference is that the Woodpecker was a pulsed radar, that is one of the reasons it seemed so wide.

Some radars are more continuous, sometimes setting on one frequency for hours at a time.  For example, the Chinese OTH-B radars, the French Nostrodamus, the Russian 29B6, and the British PLUTO, all might set on a freq for hours at a time.  By the same token, all of those radars can, when needed, change frequency, and sometimes might do it in minutes.

OTHRs changing frequency is part of how they control what portion of the Earths surface they are illuminating.  Think of it this way, OTHR antennas typically can steer the beam in Azimuth, but not in Elevation.  So they can point the beam in the direction they want, but to control where on the Earth it is going to "come down" they must control the takeoff angle, and so the angle of reflection off the ionosphere.  You could build an antenna that could control elevation, that is not problem technically, but that by itself would not do you much good, the ionosphere must also be reflective at that angle.  Instead of building an array that steers in elevation if you just pick the frequency that currently reflects off the right altitude of ionosphere to give you the angle you want you can still achieve the same thing, in a more simple antenna design.

So that accounts for OTHRs gross frequency steps (think of this like bands), but not the small frequency steps around the same band segments (specific frequencies within the bands).

The small bursts and frequency steps serve a few different purposes.  For example, jumping around like that might make you less susceptible to interference.  Setting on one frequency if there is any interference in your bandpass it hits you all the time, jumping around it only hits you part of the time and you can integrate it out.  Another issue is that a specific pulse repetition interval and a specific frequency will have a specific set of "blind speeds" and ranges.  Jumping around in frequency and PRI will eliminate those blind speeds and ranges.

ANd of course there are other factors, but that is a 101 level partial introduction to why they hop and move.


This is either a radar (OTHR, Over The Horizon Radar) or it is an ionospheric sounder.  In this case probably a radar.

Why do I say it can be either?

Ionospheric sounders are, at their cores, radars.  The target set is the ionosphere, instead of man made things like ships, aircraft, or missiles.  Since they are radars they can use transmission waveforms that are very similar to OTHRs.  In fact, they can use techniques that are identical to what an OTHR might use, although typically there are slight differences.

In this case your waveform appears to be FMCW, and that is used by both OTHRs and sounders.  However, the burst looks a bit short and the rep rate a bit high to be an ionosonde, so it is most likely an OTHR.

One way to narrow down the possibilities is to look at how often the particular signal hits.  Think about the target sets for each, an ionosonde and an OTHR.  The OTHR looks for man made targets that tend to move fairly rapidly, while the sounder looks at the ionosphere which tends to move (or change) more slowly.  So sounders tend to transmit less often, say a few times an hour, while OTHRs tend to transmit more often, either continuously or several times a minute (sometimes across multiple freqs) is not uncommon.

There are also other ways to ID the signals, such as frequency excursion limits, burst pre-tones, and rep rates / specific bandwidth combinations.


Spy Numbers / Re: Number station 9.330mhz
« on: December 21, 2020, 1725 UTC »
Look up "Cuban HM01 numbers station", that is what you are describing, and 9330 kHz is one of their long standing frequencies.  You could look here:   https://priyom.org/number-stations/digital/hm01

The "jamming" noise is not jamming, rather it is digital data sent by the station.

The below is not being a spelling/grammar Nazi, just an FYI if you did not already know.  I don't particularly care if you use the right units or not, that is up to you.

We all know what you meant by "mhz", it is in somewhat common, if incorrect, use, however the format is wrong and does not mean what you think it means (shades of Inigo Montoya there).  MegaHertz is written MHz (capital M, Capital H).  When you write it with a small "m" you are actually saying "milliHertz".  Since both are real things, it can't be both.  9.330 mHz is real and is a different frequency different from 9.330 MHz.


HF Beacons / Re: New Dasher 4097.22 KHz ?
« on: December 15, 2020, 0032 UTC »
Sorry, I am easily confused.  Is the 4097.2 the old Inyo Whooper?  Or rather do you mean the new DW is the old Whooper?


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