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Shortwave Pirate / Re: YHWH 11560 AM 2304 UTC 18 JAN 2020
« on: January 19, 2020, 0020 UTC »
I noticed the carrier before 2240z, however it did not get up to usable levels until about 2250z.  Closing music, "Days of Hard Life" by Lace, started about 2349z, and carrier off about 2353z.


Shortwave Pirate / Re: UNID 4067 USB 00:16UTC Jan17 2020
« on: January 18, 2020, 0046 UTC »
S4 or so here in the Mojave Desert of California.  OM talking @ 0045z, but could not make it out.  Into a bluesy song.


Testing 1 2 3 can anybody hear me @0100 UTC on 6935 kHz, USB.  Good signal into the Mojave Desert tonight.

Wolverine Radio ID just before music starts @0102z.

Wolverine announced move to 4065 kHz at 0104z.

"Testing 1 2 3 can anybody hear me" on 4065 kHz USB @0106 UTC.  6935 kHz was a little bit better for me, but 4065 is decent also.


Spy Numbers / UM10 network
« on: January 11, 2020, 1424 UTC »
And just to revisit this, because you know, why not every few years.

Frequency sets seem to have shifted around.  I have been hearing OBCD on 3207 kHz at H+10 and H+50, and L6YC on 3860 kHz at H+15 and H+45.  I have not yet found the second freq for either of them, and I have looked at all the freqs in this thread.


Spy Numbers / Re: "V13" New Star Broadcasting
« on: January 11, 2020, 1407 UTC »
1305z weak CC numbers/1331z oriental flute music w/deep fading 30 Dec 2019 7688kHz USB

What SDR your using to listen to V13?

@shadypyro, this 1300 and 1330 UTC window for V13 can often be heard on my Mojave Desert remote, however it is not often very strong there.  I typically hear it better on one of the Japanese remotes.


Spy Numbers / Re: "V24"
« on: January 07, 2020, 0051 UTC »
5 Jan /20
6215kHz AM
Carrier noted on at 1444z
1500z Opening K-pop song "Shouldn't Have ..."; numbers in KK at 1503z; until 1509z

Copied with a fair signal in Denver on my RSPdx and G5RV inverted V dipole. The carrier seemed to be carrying crosstalk with some other station, which remained on well after V24 ceased its broadcast. Or perhaps there's a new station also occupying that frequency? It's still on as of 1604 UTC. It would be very unlike V24 to remain on so long after the message is sent, so perhaps that's the better explanation, but not getting enough of anything to make out what it might be.

Sound of Hope, Chinese service, started using this frequency in December of 2019.

So for the 1500 UTC transmission on 6215 kHz you will have SoH up before the V24 carrier comes up, and SoH will still be there after V24 goes away.  Fortunately V24 has almost always been stronger than V24 on this when they are co-channel.  And yes, V24 still also has its audio cross talk.


General Radio Discussion / Re: TDoA Questions & maybe an article?
« on: January 01, 2020, 1435 UTC »
I've been working on the Pirate Radio Annual; it's going to be a long haul & I'm nowhere close to finished with it. I've just been starting to think about articles, etc. for it. One that I was thinking about was TDoA and if any measures can be taken to skew the results.

Are you specifically talking about impacting the ability of hobbyist or hobby networks like the Kiwi TDOA plug in?  Or are you worried about professionals?

At the hobby level you may be able to reduce the accuracy, but probably not at the professional level.

* use two transmitters on exactly the same frequency from somewhat different locations that are fed with an Internet audio feed to keep the audio in sync
* use an AM transmitter in one location to lay down a carrier on a frequency and an SSB transmitter in a different location to modulate the carrier

The multi transmitter solution has the most probability of success, as long as they are all the same mode.  What is that going to do to the audio though?  Propagation delays will produce echoes, even if the audio starts out in sync.

Use of an AM transmitter combined with an SSB signal will not prevent or degrade TDOA.  For the purposes of TDOA you can ignore (in fact, most hobby based applications probably do this) the carrier as it has no easily / grossly identifiable features.  Instead you look only at the modulation and you correlate events in the modulation between the samples taken.

Other less active possibilities seem to be:

* use of frequencies with a smaller ground wave
* use of antennas with low-angle radiation
* use of directional antennas

Short of reducing the area over which a transmission is heard none of these will be useful.  TDOA works regardless of the propagation technique, direct path, ground wave, sky wave, short of backscatter there is little that can be done there.  Direct path may be the most accurate, but good results can be achieved with any kind of propagation that does not involve angular multipath or backscatter.

So I also wonder about the general accuracy of the TDoA results while just simply broadcasting on 43m with dipole or a nondirectional antenna. Has anyone noticed that the results are more or less accurate on different frequencies (e.g., 4 MHz vs. 6.9 MHz, etc.)? Any other variables?

The accuracy of Kiwi type TDOA applications is highly variable.  The accuracy of professional systems much less so.

Professional sensors can use TDOA or combinations of TDOA and other techniques to plot the source of a transmission at significant distances to very small areas.  I have used TDOA and other passive systems capable of plotting the position of a target at 10's of km to within a few meters, at hundreds of km to within a large city lot, and at thousands of km to within a few miles.

Long range TDOA, thousands of km, gets you close, short range TDOA or other techniques get you exact.

TDoA's accuracy is IMHO highly overrated. I am not sure why it would be a concern to pirate operators, the FCC has significantly better technology (as has for a long time).

<<<<snip some relevant stuff>>>>

As I like to joke "Propagation gives your location away".

I 100% agree when you are talking about hobby TDOA like the Kiwi system.

And yes, it has always been possible to get a good idea where an operator was, at least to the general region.  With that information, and if you really wanted to invest the time and expense, you could use other techniques to find the exact location.

Since hobby TDOA became widely available I have plotted, for my own information, the majority of pirates I have heard on HF.  I have not shared those results with anyone, and see no reason to, but in general there have been very few surprises, most of the ops appear to be transmitting from about the locations I previously thought.  The availability of TDOA generally has not revealed ops locations to me that I did not already suspect.

There's one idea I can think of that might work - use very low power. The weaker you can make your signal, the larger the TDoA error will be. Probably not an ideal solution, however.

Distributed low power transmitters, a network of multiple transmitters working at low enough power to not deliver usable energy to more than a couple of TDOA nodes, would work, but is not practical in this application.

If no more than 2 TDOA nodes can receive a given signal you cannot resolve its location.  If the third node is receiving the, seemingly, same signal (or two versions of the same signal, one weak and one significantly stronger) from a different transmitter location then the plotted results will be garbage.

I understand the concern operators have... but think TDoA may be overrated. It's not helping the FCC. I guess if an operator is really concerned about listeners knowing roughly where they are located (as in, in one of these states here, or maybe one of those states over there...) it may be an issue.

This.  Professional facilities already have (and have had for some time) the ability to plot with far greater accuracy than the hobby TDOA systems like Kiwi can deliver.  The hobby TDOA solutions just bring a "lite" version of that technology to the common man.

If anyone with nation-state pockets is looking at you they will find you, the question is do they have the time, manpower, or desire to look for you?

The other factor I didnít see mentioned is where some receivers are getting single hop reception and others are ground wave or multiple hops.  That will impact the position estimate unless the TDOA algorithm corrects for that.

The varying height of the reflecting ionosphere (which can be different for each receiver site) impacts the accuracy.  Picking receiver sites on either side of the day/night terminator could have an impact on accuracy. If you could get receiver stations that all heard the xmtr via ground wave then the position estimate could be very good...but you already have a good idea of where they are then donít you?

Only if you are trying to get accuracy measured in a few km at extended distances.

And that is a key.  No TDOA system, pro or otherwise, in one plot yields a street address at thousands of km distances.  But it can get you to within direct path or ground wave receive distances from that far.  Then stage 2 is getting to that approximate location and using local techniques (can be TDOA also, or maybe just AOA).  Of course, if you start in the general area and know you are there (say by propagation characteristics) then local techniques can be used initially.


General Radio Discussion / Re: Radio to the rescue!!
« on: January 01, 2020, 1329 UTC »
Valid concern, no doubt, a possibility that cannot be fully ignored.  However I think (my opinion) even China and Russia would not give NK the ability to start WW III or, more importantly, the ability to strike at them if NK got mad enough.  These sats spend as much time over China and Russia as they do over the US.  An EMP over the US may badly hurt some of our home based responses, but would not hurt in the least our distributed response capability.  Such a device may reduce the US counter strike capability, but would not eliminate it, it may stagger the US, particularly the citizenry, but would not eliminate the US military or intelligence apparatus.  You can't hide these sats, or any sat really, so the platform would never be in question, and you cannot hide the signature of the weapon used so the source of the device would be revealed.  Such an attack, by itself, could not quickly topple the US so unless someone is willing to follow up such an event with other, more direct, strikes, all it does is scream "hit me in the face, please".  So I don't see a lot to gain by either China or Russia providing such a device to NK.

Sure, provide them some raw material, provide them some tech support, all that does is allow them to, eventually, build the weapons themselves with a verifiable technology and effort backtrail.  I think that is what we see in the historical record, no unexplanable tech jumps from externally delivered / developed items, and that record just does not support such a device being available to NK in time for those launches.

Today might be a different story, today NK may be able to orbit such a device, maybe.  But probably not in 2016, and almost certainly not in 2012.

Just my opinion.


Shortwave Pirate / Re: UNID 4065 USB 0149 UTC 1 January 2020
« on: January 01, 2020, 0152 UTC »
Station is S5 and wide audio here in the Mojave Desert of California.  No ID heard yet.


0142z, S4 to S5 into the Mojave Desert of California.


Shortwave Pirate / Re: Zeke's Attic 4245 USB 0120 UTC 1 OCT 2018
« on: January 01, 2020, 0145 UTC »
0142z, S3 to S4 into the Mojave Desert of California.

0152z talking about not being able to find stuff at garage sales anymore, I assume records.


General Radio Discussion / Re: Radio to the rescue!!
« on: December 31, 2019, 1313 UTC »
Interesting piece, seems someone can pop a nuke anywhere in orbit and fry stuff around the world. Also note that NK has two "sats" up, they fly over the US a few times a day but apparently have not emitted a peep, causing some to speculate they're emp weapons rather than comsats.

The NKs claim the sats are "Earth observation platforms".  Both were supposed to contain UHF transmitters and X band telemetry.  The NKs have claimed that the UHF links were used to send patriotic music but no one outside NK ever reported hearing such.

However the first one is in a rapid tumble (can be visually confirmed by anyone with a tracking telescope, I have seen it myself with my own equipment) and has never been confirmed to have sent any transmissions.  This means that whatever it is it is probably dead / defunct.  Such an uncontrolled tumble would result in power and communications issues, at the least.

The second one is twice as large (about 200 kg) and while it was initially reported as tumbling the tumbling appears to have been brought under control and the sat has made at least one apparently commanded / intentional orbital change.  It also has never been confirmed to send any transmissions, however the fact it was tumbling, then stabilized, and made an orbital change could indicate the links are alive and no one has caught them, or that there is an automated system on board to make it look like it is under control.  I lean towards the latter myself, at least until someone can determine that there is an operational link off of the bird.

Regardless, I think it very unlikely that either of these would be EMP devices.  These are the first two successful sat launches by NK.  One of the launches was in late 2012 and the other in early 2016.  Even if they can today produce a nuke in this physical size / weight range they cannot have made many of them.  It is very unlikely they could have done so in 2012, at that time they had only had 2 partially successful nuclear tests, and nothing even remotely approaching the yield needed for a useful EMP device.  Prior to the 2016 launch they had one more test that was probably their first somewhat successful test, a device on the order of the yield of the US WW II weapons.  Still too small for any kind of useful space based EMP device.  It was not until well after the launch of the 2016 satellite that NK demonstrated the first weapon that might be large enough to be a usefull space based EMP device.

I think that today the NKs could probably produce a useful yield EMP device.  I really don't know if they could package it to put it into a ~200'ish kg total all up weight satellite.  But even assuming they could today, there is no indication they could (and many indicators it is very unlikely) prior to the launch of either of their two successful sat launches.  Today it is assumed NK has ~25'ish nukes, 4 years ago they did not.  Trying to put one into space, with a launch program with such a low success rate at the time, seems like a bet not worth taking, the few weapons they had would have been valuable.

No, I doubt the current NK sats are anything more than test articles.  They may have been modeled to prepare for future nukes, but I just can't see the existing, in orbit, items being anything of danger.  I would be surprised if they were more than a camera, some basic TM, and the basics required to stabilize a sat in orbit.


HF Mystery Signals / Re: UNID "Time Signal" at 7475 in AM mode
« on: December 29, 2019, 1714 UTC »
It also seems that depending on which stations you use you can end up with very different results for the TDoA. Quite interesting.

This kind of results can sometimes be an indicator that there is more than one synchronized transmission on a given frequency.  In fact, multiple sync'ed transmission sources is one way to intentionally spoof TDOA.  I have seen it used in various military applications.

Not saying that is what is causing your results, I don't know, but it is something to keep in mind.


Latin American Pirate / AD149 Radio ? 6934.9 AM 0050 UTC 29 Dec 2019
« on: December 29, 2019, 0059 UTC »
A so far UNIDed station has been up and down a few time, with a few songs, on 6934.9 kHz AM since maybe 0040 UTC.  Signal has been weak, but I have heard music.  At 0054 clearly heard Kiss's "I was made for loving you".


HF Mystery Signals / Re: UNID "Time Signal" at 7475 in AM mode
« on: December 27, 2019, 1836 UTC »
There is another way to TDOA besides Kiwi, this signal might be a good candidate for that, but we would need 3 listeners addressing the signal.

The signal, on arrival at my location, is delayed from GPS T0 by ~6.6 msec.  Assuming (just as an experiment) the transmission is synchronized to the GPS second that puts it almost dead on the money 2000 km from me.  Or near this circle:

Of course, the timing my not be coincident with GPS T0, and then that circle means nothing.  But it does appear to be stable with / in sync with GPS.


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